Abstract
Background
Eletriptan (Relpax) is a new triptan soon to be made available by prescription for the treatment of acute migraine. Currently five triptans are available by prescription and more are under development. In light of the many drugs for treating acute migraine, there is a need for evidence‐based assessments to help determine the relative efficacy and harm of these treatments.
Objectives
To determine the efficacy of eletriptan for treating a single migraine attack using the outcomes of headache response and pain‐free response at 0.5, 1, 2 and 4 hours, and sustained relief over 24 hours. To express efficacy in terms of number‐needed‐to‐treat (NNT). To determine the adverse effects of a single dose of eletriptan and express this in terms of number‐needed‐to‐harm (NNH). To allow for the comparison of the efficacy of eletriptan with other migraine treatments evaluated systematically in the same way.
Search methods
Data from all Phase III randomised placebo‐controlled trials were made available by the manufacturer, Pfizer Inc. To date, these trials comprise the only data on eletriptan relevant to this review in a published or unpublished form; thus, searches of electronic databases for further trials of eletriptan were not conducted. Date of last search: January 2000.
Selection criteria
Trials of eletriptan for acute migraine; randomised allocation to treatment groups, including a placebo group; double‐blind design; International Headache Society diagnostic criteria for migraine with or without aura; single migraine attack; single‐dose treatment at standard doses; adult population; baseline pain of moderate or severe intensity using a 4‐point standardised rating scale (0 = no pain, 1 = mild pain, 2 = moderate pain and 3 = severe pain); and dichotomous or percentage data for at least one of the main efficacy outcomes.
Data collection and analysis
Trials were scored for quality and data extracted by two independent reviewers. Dichotomous or percentage data were extracted and pooled to calculate the relative benefit (RB) or relative risk (RR) and NNTs or NNHs for a number of outcomes for eletriptan 20 mg, 40 mg and 80 mg. The main outcomes considered were headache response at 1 and 2 hours, pain‐free response at 2 hours, sustained relief over 24 hours and adverse effects. Minor outcomes considered were headache response at 0.5 and 4 hours, and pain‐free response at 0.5, 1 and 4 hours.
Main results
Six trials met the inclusion criteria. Significant benefit of eletriptan over placebo was shown for eletriptan 20 mg, 40 mg and 80 mg for the primary efficacy outcomes of headache response and pain‐free response at 2 hours. For headache response at 2 hours, the NNTs (with 95% confidence intervals) were 4.4 (3.4 to 6.2), 2.9 (2.6 to 3.3) and 2.6 (2.4 to 3.0) for eletriptan 20 mg, 40 mg and 80 mg, respectively. For pain‐free response at 2 hours, the NNTs were 9.9 (6.9 to 18), 4.0 (3.6 to 4.5) and 3.7 (3.4 to 4.2), for eletriptan 20 mg, 40 and 80 mg, respectively.
There was no significant difference in the incidence of major adverse effects between any dose of eletriptan and placebo. The incidence of minor adverse effects was significantly higher for all eletriptan doses than for placebo, with NNHs of 11 (95% confidence interval, 6.2 to 39), 7.0 (5.2 to 11) and 3.7 (3.1 to 4.5) for eletriptan 20 mg, 40 mg and 80 mg, respectively.
Authors' conclusions
Eletriptan 20 mg, 40 mg and 80 mg are effective for the treatment of an acute migraine attack. Effectiveness is dose‐related, with statistically significant differences between doses for pain‐free response and 24‐hour outcomes. Eletriptan compares well with other triptans available for outcomes measured up to 2 hours and provides meaningful relief for 24 hours. Taken as a single dose, eletriptan was well tolerated and caused no major harm. The incidence of minor harm was dose‐dependent, with 80 mg giving significantly more adverse effects than 40 mg.
Keywords: Humans; Acute Disease; Clinical Trials, Phase III as Topic; Indoles; Indoles/administration & dosage; Indoles/adverse effects; Migraine Disorders; Migraine Disorders/drug therapy; Pyrrolidines; Pyrrolidines/administration & dosage; Pyrrolidines/adverse effects; Randomized Controlled Trials as Topic; Serotonin Receptor Agonists; Serotonin Receptor Agonists/administration & dosage; Serotonin Receptor Agonists/adverse effects; Tryptamines
Eletriptan for the treatment of acute migraine in adults
Migraine is a significant health problem affecting about 18% of women and 6% of men, and many drugs are available for its treatment. Eletriptan is a new drug which will soon be available by prescription. Data from trials undertaken by the manufacturer and analysed independently by the reviewers showed that treatment of an acute migraine attack with eletriptan 20 mg, 40 mg or 80 mg provided significant pain relief from 0.5 to 24 hours. The incidence of adverse effects was dose‐related, with patients taking eletriptan 80 mg reporting more adverse effects.
Background
Migraine is a significant health problem affecting about 18% of women and 6% of men (Scher 1999). The impact of migraine on the individual, the health service and society is significant as attacks can last up to 48 hours and may occur frequently. The decrease in productivity and loss of work days has been estimated to cost as much as US$14 billion (Hu 1999). Yet more than half of migraine sufferers never seek medical advice about treatment options, relying instead on over‐the‐counter drugs (Lipton 1993; Dowson 1999).
There are a number of medicines available over‐the‐counter and by prescription for the treatment of acute migraine attacks, but there is little evidence‐based information about their relative efficacy. It is important to be able to compare relative efficacy and safety in order to make informed decisions about which agent to prescribe. Large randomised trials making direct comparisons between migraine drugs would provide data on their relative efficacy and safety. Few such trials exist. There are few published large randomised trials of direct comparisons between triptans, and most randomised trials of other migraine drugs are too small to have sufficient power for their estimates of relative efficacy and safety to be credible. An alternative method of estimating relative efficacy is by indirect comparisons of each drug with placebo. By pooling data from individual trials of a drug versus placebo with the same definition of migraine, pain outcome measures, and trial design, the number‐needed‐to‐treat (NNT) for the outcome of choice can be estimated. By using these same criteria for each drug it is possible to produce a rank order of NNTs that describes clinically relevant pain relief. The information in this review can then be compared with information about other migraine drugs determined in the same way (Oldman submitted (2); Tfelt‐Hansen 1998).
Eletriptan (trade name 'Relpax') is one of the newest triptans and will soon be available by prescription for the treatment of acute migraine. Systematic reviews of treatments, which aim to provide information on the relative efficacy and harm of available drugs, enable evidence‐based recommendations for the treatment of acute migraine to be developed.
Objectives
The objective of this review is to evaluate quantitatively the analgesic efficacy and harm of a single dose of eletriptan for the treatment of a single acute migraine attack. The calculation of NNTs for eletriptan 20 mg, 40 mg and 80 mg will, in the future, allow comparisons to be made between triptan migraine treatments.
Methods
Criteria for considering studies for this review
Types of studies
The inclusion criteria were:
trials of eletriptan for acute migraine
randomised allocation to treatment groups, including a placebo group
double‐blind design
single migraine attack
single‐dose treatment at standard doses
dichotomous or percentage data for at least one efficacy outcome.
Multiple‐attack and multiple‐dose trials were included provided that single‐dose information for attack one was available.
Types of participants
Included patients were adults with migraine with or without aura diagnosed according to International Headache Society criteria (IHS 1988). Baseline pain was required to be of moderate or severe intensity using a four‐point standardised rating scale (0 = no pain, 1 = mild pain, 2 = moderate pain and 3 = severe pain).
Types of interventions
Trials were included if they contained a placebo group and at least one group in which eletriptan was given as a single dose for a single migraine attack with no rescue medication permitted for at least two hours.
Types of outcome measures
Currently there is no universal agreement on which outcomes are most important in acute migraine trials, despite the publication of guidelines by the International Headache Society (IHS 1991). Patients have rated
complete pain relief
no headache recurrence,
rapid onset of pain relief
no adverse effects
as the four most important outcomes (Lipton 1999).
The traditional long‐term measure of treatment efficacy has been headache recurrence within 24 hours. However, the way this outcome is commonly reported is variable, and a more rigorous alternative may be sustained relief or pain‐free response over 24 hours (Ferrari 1999). We therefore extracted dichotomous data for the following outcomes:
Main outcomes: i) Headache response (headache pain reduced from moderate or severe to mild or none) at two hours; ii) Headache response at one hour; iii) Pain‐free response (headache pain reduced from moderate or severe to none) at two hours; iv) Sustained relief over 24 hours (headache response at two hours, maintained for 24 hours after treatment (i.e., pain did not return to moderate or severe), with no stated use of rescue medication or a second dose of study medication); v) Adverse effects.
Minor outcomes: vi) Headache response at half‐an‐hour; vii) Headache response at four hours; viii) Pain‐free response at half‐an‐hour; ix) Pain‐free response at one hour; x) Pain‐free response at four hours.
Search methods for identification of studies
Unpublished data from all Phase III randomised placebo‐controlled trials world‐wide were made available by Pfizer Inc. To date, these trials comprise the only data on the effectiveness of eletriptan relevant to this review in a published or unpublished form; thus, searches of electronic databases for further trials of eletriptan were not conducted.
Data collection and analysis
From each trial we extracted the number of patients treated per group, dosing regimes, details of study design (parallel or crossover, multiple‐ or single‐attack) and timing/type of rescue medication.
For headache response, pain‐free response and sustained relief over 24 hours, the proportions of patients achieving the outcome in the active and placebo groups were used to calculate relative benefit (RB) (used here to denote the relative risk of a positive outcome, e.g., headache response) and number‐needed‐to‐treat (NNT).
For all efficacy outcomes, data contaminated by rescue medication or a second dose of study medication were not extracted. Where data on sustained relief over 24 hours were not explicitly reported, they were calculated by subtracting the number of patients whose headache had recurred by 24 hours from the number who had had a headache response at 2 hours. To ensure that the 24‐hour data were not contaminated by rescue/second dose medication, this outcome was calculated only when it was clear that i) patients had been instructed to use rescue medication only if headache pain became moderate or severe, or ii) authors stated that the data were not contaminated by further medications.
An important consideration in migraine trials is what constitutes a sensible denominator for calculations. While all patients randomised would usually be the ideal, migraine trials commonly include patients who are randomised but do not have an attack during the study period and thus do not contribute data to the analysis. For this reason we chose to use the number of patients randomised who had a migraine attack of moderate or severe intensity as the denominator for calculation. In some cases ‐‐ e.g., in determining 24‐hour outcomes ‐‐ this was not possible, and when this occurred we used the number of patients randomised.
Relative risk (RR) and number‐needed‐to‐harm (NNH) were calculated for the number of patients reporting treatment‐related adverse effects. These are described as major harm, minor harm and individual adverse effects. Major harm was defined as the number of patients in each treatment group reporting any adverse effect resulting in death or serious illness or any adverse effect of sufficient severity to cause withdrawal from the study. Minor harm was defined as the number of patients in each treatment group reporting any adverse effect. Also analysed was the number of patients in each treatment group reporting individual adverse effects (e.g., asthenia, dizziness).
Adverse effect data were extracted for patients receiving one dose of eletriptan only, but may also include non‐triptan rescue medication and concomitant medication. Data on adverse effects were collected over seven days following the start of the study using patient diaries. Whilst these kind of data do not represent a clean data set, we decided to present these data in order to provide information regarding the adverse effect profile of this new triptan.
Relative benefit (RB) and relative risk (RR) estimates were calculated with 95% confidence intervals (CI) using a fixed‐effect model (Gardner 1986). NNTs and numbers‐needed‐to‐harm (NNHs) were calculated with 95% CI (Cook 1995) when the RB or RR was statistically significant. A statistically significant difference from placebo was assumed when the 95% CI of the RB or RR did not include one. (Note that RB and RR are both described as 'relative risk' in Meta View.)
Results
Description of studies
Pfizer Inc. provided data from seven unpublished trials. (Note: one of these studies has subsequently been published ‐ see 'Studies awaiting assessment). Six trials met the inclusion criteria. These trials provided data on 3224 patients (349 received eletriptan 20 mg, 1224 received eletriptan 40 mg, 1221 received eletriptan 80 mg, and 779 received placebo). Detailed information on each study is provided in the table describing the 'Characteristics of included studies'.
We excluded one multiple‐attack trial from the efficacy analysis because it was not possible to extract information on the first attack treated (Pfizer 1999g). Adverse effect data from this trial were, however, included in the analysis (Pfizer [AEs only]).
Risk of bias in included studies
Each report was read independently by AO and LS and scored using a 5‐item, 0‐5 point, quality scale (Jadad 1996).
The scale used is as follows: Is the study randomised? If yes, one point Is the randomisation procedure reported and is it appropriate? If yes, add one point; if no, deduct one point Is the study double‐blind? If yes, add one point Is the method of double‐blinding reported and is it appropriate? If yes, add one point; if no, deduct one point Are the reasons for patient withdrawals and dropouts described? If yes, add one point
The quality scores of individual trials are reported in the 'Notes' column of the table describing the 'Characteristics of included studies'. All six included trials were of high quality and obtained the maximum score of five.
Effects of interventions
For eletriptan 20 mg, there were two trials in which 349 patients received eletriptan 20 mg and 353 received placebo (Pfizer 1999b; Pfizer 1999f). For eletriptan 40 mg and 80 mg, six trials provided data on 1224 patients receiving eletriptan 40 mg, 1221 patients receiving eletriptan 80 mg and 779 receiving placebo (Pfizer 1999a; Pfizer 1999b; Pfizer 1999c; Pfizer 1999d; Pfizer 1999e; Pfizer 1999f). The relative benefit (RB) and number‐needed‐to‐treat (NNT) for each outcome are listed below. Numbers in parentheses are 95% confidence intervals (CI).
Efficacy results for all outcomes except the 24‐hour outcome were based on an intention‐to‐treat analysis that excludes protocol violators, but includes data from withdrawals and dropouts. For the 24‐hour outcome, we were unable to calculate this information, and the analysis is based on the intention‐to‐treat population as defined in the original studies.
NNTs have not been calculated where the RB is not significant (i.e., where the confidence interval crosses one).
Results for eletriptan versus placebo were as follows:
Main outcomes:
i) Headache response (moderate to severe pain reduced to mild or none) at 2 hours: Eletriptan 20 mg: RB 2.04 (1.62 to 2.56); NNT 4.4 (3.4 to 6.2); n = 702 Eletriptan 40 mg: RB 2.38 (2.09 to 2.72); NNT 2.9 (2.6 to 3.3); n = 2003 Eletriptan 80 mg: RB 2.50 (2.19 to 2.85); NNT 2.6 (2.4 to 3.0); n = 2000
ii) Headache response at 1 hour: Eletriptan 20 mg: RB 1.98 (1.39 to 2.82); NNT 12 (7.2 to 40); n = 702 Eletriptan 40 mg: RB 2.33 (1.91 to 2.84); NNT 5.6 (4.8 to 7.2); n = 2003 Eletriptan 80 mg: RB 2.48 (2.03 to 3.02); NNT 5.0 (4.3 to 6.1); n = 2000
iii) Pain‐free response (moderate to severe pain reduced to none) at 2 hours: Eletriptan 20 mg: RB 3.09 (1.82 to 5.24); NNT 9.9 (6.9 to 18); n = 702 Eletriptan 40 mg: RB 5.96 (4.30 to 8.27); NNT 4.0 (3.6 to 4.5); n = 2003 Eletriptan 80 mg: RB 6.40 (4.62 to 8.85); NNT 3.7 (3.4 to 4.2); n = 2000
iv) Sustained relief over 24 hours (headache response at 2 hours, sustained for 24 hours, with no rescue medication and no second dose of study medication): Eletriptan 20 mg: RB 2.01 (1.34 to 3.01); NNT 5.1(3.3 to 11.1); n = 270 Eletriptan 40 mg: RB 2.55 (2.14 to 3.05); NNT 3.6 (3.1 to 4.2); n = 1819 Eletriptan 80 mg: RB 3.01 (2.53 to 3.58); NNT 2.8 (2.5 to 3.2); n = 1822
v) Treatment‐related adverse effects: Major harm (adverse effects resulting in death, serious illness or withdrawal from study): Eletriptan 20 mg: RR 0.70 (0.19 to 2.63); NNH not calculated; n = 499 Eletriptan 40 mg: RR 0.64 (0.26 to 1.56); NNH not calculated; n = 1476 Eletriptan 80 mg: RR 1.08 (0.49 to 2.42); NNH not calculated; n = 1302
Minor harm (any adverse effect): Eletriptan 20 mg: RR 1.57 (1.08 to 2.28); NNH 11 (6.2 to 39); n = 499 Eletriptan 40 mg: RR 1.51 (1.20 to 1.90); NNH 7.0 (5.2 to 11); n = 1476 Eletriptan 80 mg: RR 2.04 (1.63 to 2.56); NNH 3.7 (3.1 to 4.5); n = 1302
All adverse effects were relieved on discontinuation of the study drug. None were life‐threatening.
Individual adverse effects:
Only those adverse effects for which there was a significant difference between active and placebo groups are reported here. Where the RR was not significant, data are not presented.
Dizziness: Eletriptan 40 mg: RR 2.54 (1.14 to 5.67); NNH 27 (18 to 50); n = 1476 Eletriptan 80 mg: RR 3.14 (1.38 to 7.14); NNH 18 (13 to 30); n = 1302
Asthenia: Eletriptan 80 mg: RR 3.28 (1.69 to 6.35); n = 1302
Minor outcomes:
vi) Headache response (moderate to severe pain reduced to mild or none) at 0.5 hour: Eletriptan 20 mg: RB 1.01 (0.52 to 1.95); NNT not calculated; n = 702 Eletriptan 40 mg: RB 1.65 (1.08 to 2.52); NNT 37 (21 to 179); n = 1744 Eletriptan 80 mg: RB 2.26 (1.51 to 3.38); NNT 22 (14 to 51); n = 1745
vii) Headache response at 4 hours: Eletriptan 20 mg: RB 2.13 (1.79 to 2.55); NNT 2.9 (2.4 to 3.7); n = 702 Eletriptan 40 mg: RB 2.33 (1.96 to 2.78); NNT 2.5 (2.2 to 3.0); n = 713 Eletriptan 80 mg: RB 2.39 (2.01 to 2.84); NNT 2.4 (2.1 to 2.9); n = 718
viii) Pain‐free response (moderate to severe pain reduced to none) at 0.5 hour: Eletriptan 20 mg: RB 2.02 (0.19 to 22.1); NNT not calculated; n = 702 Eletriptan 40 mg: RB 1.63 (0.38 to 7.05); NNT not calculated; n = 1744 Eletriptan 80 mg: RB 4.50 (1.20 to 16.9); NNT 70 (47 to 143); n = 1745
ix) Pain‐free response at 1 hour: Eletriptan 20 mg: RB 2.43 (0.87 to 6.82); NNT not calculated; n = 702 Eletriptan 40 mg: RB 5.00 (2.54 to 9.85); NNT 22 (16 to 32); n = 2003 Eletriptan 80 mg: RB 9.67 (5.00 to 18.7); NNT 10 (8.3 to 12); n = 2000
x) Pain‐free response at 4 hours: Eletriptan 20 mg: RB 2.63 (1.93 to 3.58); NNT 4.8 (3.7 to 6.8); n = 702 Eletriptan 40 mg: RB 3.30 (2.45 to 4.45); NNT 3.4 (2.8 to 4.3); n = 713 Eletriptan 80 mg: RB 3.55 (2.64 to 4.77); NNT 3.1 (2.6 to 3.8); n = 718
Discussion
This meta‐analysis shows that eletriptan is an effective drug for the treatment of an acute attack of migraine, with low NNTs for the main outcomes. For these outcomes, eletriptan 40 mg and 80 mg compare well with other triptans evaluated using identical methodology (Oldman submitted (2)).
All doses of eletriptan were statistically significantly better than placebo for all the main outcomes. For the minor outcomes, eletriptan was statistically significantly better than placebo except in the following cases: there was no significant difference between eletriptan 20 mg and placebo for headache response at 0.5 hour, pain‐free response at 0.5 hour or pain‐free response at 1 hour, and no significant difference between eletriptan 40 mg and placebo for pain‐free response at 0.5 hour.
There was a statistically significant dose response between 20 mg and 40 mg for all the main outcomes, but none of the minor outcomes. For the main outcomes, NNT confidence intervals did not overlap, suggesting that this is a clinically relevant difference.
Although confidence intervals for NNTs for eletriptan 40 mg and 80 mg overlap slightly, there was a statistically significant difference based on a z test (Tramer 1997) for pain‐free response at 2 hours and sustained relief over 24 hours, but not for headache response at 1 or 2 hours. The only minor outcome showing a statistically and clinically significant dose response between 40 mg and 80 mg was pain‐free response at 1 hour. For all other minor outcomes there was no significant difference between these doses.
There was no significant difference in the incidence of major harm between placebo and eletriptan at any dose. There were significantly more adverse effects (minor harm) with all eletriptan doses than with placebo. There was no difference between eletriptan 20 mg and 40 mg, but significantly more adverse effects were reported with eletriptan 80 mg than with eletriptan 40 mg. Individual adverse effects reported most frequently in patients receiving eletriptan 80 mg were asthenia and dizziness.
The NNTs have been calculated by pooling data from high‐quality trials which are clinically homogeneous (same diagnosis of migraine, same outcome measures, same baseline pain, same trial methodology). This approach to data pooling negates the need for statistical tests of heterogeneity, which are likely to be inaccurate (Gavaghan 2000).
Although NNHs have been calculated, it is important to remember that these are based on specific adverse effects information collected over a specific period of time. They have been presented here in order to provide a more complete picture of the efficacy and harm associated with eletriptan. It would be misleading if these NNHs were used in comparison with other estimates of harm for migraine drugs, as the methods used to collect the information are likely to be different.
Efficacy information from this review can be compared with other meta‐analyses carried out using identical methodology (Oldman 2001; Oldman submitted (2)). Such comparisons may facilitate the development of evidence‐based guidelines for migraine treatment.
Authors' conclusions
Eletriptan is an effective treatment for acute migraine. Pain relief is dose‐dependent, with eletriptan 80 mg providing statistically significantly greater pain relief than 40 mg at two and 24 hours. Eletriptan 20 mg is the least effective. Taken as a single dose, the available data suggests eletriptan was well tolerated and caused no major harm. The incidence of minor adverse events was dose‐related, with 80 mg causing significantly more adverse effects than 40 mg. All reported adverse effects were transient and reversible on discontinuation of the drug.
The trials were of high quality and provided a substantial amount of data on the efficacy of eletriptan. Further trials should reflect patients' needs and collect information on outcomes of interest to patients. Long‐term outcomes ‐‐ such as 24‐hour sustained relief and pain‐free response ‐‐ are likely to discriminate between drugs and are of particular interest. Cost‐benefit analyses based on efficacy outcomes could also demonstrate which drugs offer real advantages. Higher quality collection and reporting of adverse effects (such as nausea and vomiting) is needed.
Acknowledgements
Pfizer Ltd (UK) and Pfizer Inc provided data on file. Pfizer Inc. provided access to unpublished Phase III clinical trial data.
Data and analyses
Comparison 1.
Eletriptan 80 mg versus placebo
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
|---|---|---|---|---|
| 1 Headache response at 0.5 hour | 5 | 1745 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.26 [1.51, 3.38] |
| 2 Headache response at 1 hour | 6 | 2000 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.48 [2.03, 3.02] |
| 3 Headache response at 2 hours | 6 | 2000 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.50 [2.19, 2.85] |
| 4 Headache response at 4 hours | 2 | 718 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.39 [2.01, 2.84] |
| 5 Pain‐free response at 0.5 hour | 5 | 1745 | Risk Ratio (M‐H, Fixed, 95% CI) | 5.55 [1.28, 24.09] |
| 6 Pain‐free response at 1 hour | 6 | 2000 | Risk Ratio (M‐H, Fixed, 95% CI) | 9.67 [5.00, 18.71] |
| 7 Pain‐free response at 2 hours | 6 | 2000 | Risk Ratio (M‐H, Fixed, 95% CI) | 6.40 [4.62, 8.85] |
| 8 Pain‐free response at 4 hours | 2 | 718 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.55 [2.64, 4.77] |
| 9 Sustained relief over 24 hours | 5 | 1822 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.01 [2.53, 3.58] |
| 10 Adverse effects ‐ major harm | 6 | 1302 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.09 [0.48, 2.47] |
| 11 Adverse effects ‐ minor harm | 6 | 1302 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.04 [1.63, 2.56] |
| 12 Adverse effects ‐ dizziness | 6 | 1302 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.14 [1.38, 7.14] |
| 13 Adverse effects ‐ asthenia | 6 | 1302 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.28 [1.69, 6.35] |
Analysis 1.1.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 1 Headache response at 0.5 hour.
Analysis 1.2.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 2 Headache response at 1 hour.
Analysis 1.3.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 3 Headache response at 2 hours.
Analysis 1.4.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 4 Headache response at 4 hours.
Analysis 1.5.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 5 Pain‐free response at 0.5 hour.
Analysis 1.6.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 6 Pain‐free response at 1 hour.
Analysis 1.7.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 7 Pain‐free response at 2 hours.
Analysis 1.8.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 8 Pain‐free response at 4 hours.
Analysis 1.9.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 9 Sustained relief over 24 hours.
Analysis 1.10.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 10 Adverse effects ‐ major harm.
Analysis 1.11.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 11 Adverse effects ‐ minor harm.
Analysis 1.12.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 12 Adverse effects ‐ dizziness.
Analysis 1.13.
Comparison 1 Eletriptan 80 mg versus placebo, Outcome 13 Adverse effects ‐ asthenia.
Comparison 2.
Eletriptan 40 mg versus placebo
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
|---|---|---|---|---|
| 1 Headache response at 0.5 hour | 5 | 1744 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.65 [1.08, 2.52] |
| 2 Headache response at 1 hour | 6 | 2003 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.33 [1.91, 2.84] |
| 3 Headache response at 2 hours | 6 | 2003 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.38 [2.09, 2.72] |
| 4 Headache response at 4 hours | 2 | 713 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.33 [1.96, 2.78] |
| 5 Pain‐free response at 0.5 hour | 5 | 1744 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.16 [0.36, 13.08] |
| 6 Pain‐free response at 1 hour | 6 | 2003 | Risk Ratio (M‐H, Fixed, 95% CI) | 5.00 [2.54, 9.85] |
| 7 Pain‐free response at 2 hours | 6 | 2003 | Risk Ratio (M‐H, Fixed, 95% CI) | 5.96 [4.30, 8.27] |
| 8 Pain‐free response at 4 hours | 2 | 713 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.30 [2.45, 4.45] |
| 9 Sustained relief over 24 hours | 5 | 1819 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.55 [2.14, 3.05] |
| 10 Adverse effects ‐ major harm | 7 | 1476 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.62 [0.24, 1.55] |
| 11 Adverse effects ‐ minor harm | 7 | 1476 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.51 [1.20, 1.90] |
| 12 Adverse effects ‐ dizziness | 7 | 1476 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.54 [1.14, 5.67] |
Analysis 2.1.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 1 Headache response at 0.5 hour.
Analysis 2.2.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 2 Headache response at 1 hour.
Analysis 2.3.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 3 Headache response at 2 hours.
Analysis 2.4.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 4 Headache response at 4 hours.
Analysis 2.5.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 5 Pain‐free response at 0.5 hour.
Analysis 2.6.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 6 Pain‐free response at 1 hour.
Analysis 2.7.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 7 Pain‐free response at 2 hours.
Analysis 2.8.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 8 Pain‐free response at 4 hours.
Analysis 2.9.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 9 Sustained relief over 24 hours.
Analysis 2.10.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 10 Adverse effects ‐ major harm.
Analysis 2.11.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 11 Adverse effects ‐ minor harm.
Analysis 2.12.
Comparison 2 Eletriptan 40 mg versus placebo, Outcome 12 Adverse effects ‐ dizziness.
Comparison 3.
Eletriptan 20 mg versus placebo
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
|---|---|---|---|---|
| 1 Headache response at 0.5 hour | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.52, 1.95] |
| 2 Headache response at 1 hour | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.98 [1.39, 2.82] |
| 3 Headache response at 2 hours | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.04 [1.62, 2.56] |
| 4 Headache response at 4 hours | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.13 [1.79, 2.55] |
| 5 Pain‐free response at 0.5 hour | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.08 [0.13, 75.29] |
| 6 Pain‐free response at 1 hour | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.43 [0.87, 6.82] |
| 7 Pain‐free response at 2 hours | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.09 [1.82, 5.24] |
| 8 Pain‐free response at 4 hours | 2 | 702 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.63 [1.93, 3.58] |
| 9 Sustained relief over 24 hours | 1 | 270 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.01 [1.34, 3.01] |
| 10 Adverse effects ‐ major harm | 2 | 483 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.70 [0.19, 2.63] |
| 11 Adverse effects ‐ minor harm | 2 | 483 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.57 [1.08, 2.27] |
Analysis 3.1.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 1 Headache response at 0.5 hour.
Analysis 3.2.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 2 Headache response at 1 hour.
Analysis 3.3.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 3 Headache response at 2 hours.
Analysis 3.4.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 4 Headache response at 4 hours.
Analysis 3.5.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 5 Pain‐free response at 0.5 hour.
Analysis 3.6.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 6 Pain‐free response at 1 hour.
Analysis 3.7.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 7 Pain‐free response at 2 hours.
Analysis 3.8.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 8 Pain‐free response at 4 hours.
Analysis 3.9.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 9 Sustained relief over 24 hours.
Analysis 3.10.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 10 Adverse effects ‐ major harm.
Analysis 3.11.
Comparison 3 Eletriptan 20 mg versus placebo, Outcome 11 Adverse effects ‐ minor harm.
What's new
| Date | Event | Description |
|---|---|---|
| 10 June 2019 | Amended | Contact details updated. |
History
Protocol first published: Issue 3, 2001 Review first published: Issue 3, 2001
| Date | Event | Description |
|---|---|---|
| 19 April 2010 | Amended | Published notes updated to reflect the fact that this review has now been replaced by a new published protocol: Derry S, Moore RA, McQuay HJ. Eletriptan for acute migraine headaches in adults (Protocol). Cochrane Database of Systematic Reviews 2010, Issue 4. Art. No.: CD008490. DOI: 10.1002/14651858.CD008490. |
| 21 June 2008 | Amended | Converted to new review format. |
Characteristics of studies
Characteristics of included studies [ordered by study ID]
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 4 parallel groups. Study drug self‐administered for single migraine attack of at least moderate intensity. Multi‐national (Europe, South Africa and Israel). 48hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 1, 2, 4 and 24 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=732 Age 18‐65. | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Cafergot (Ergotamine tartrate 2 mg + Caffeine 200 mg) 4. Placebo. | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: pain‐free at 1 hour. Other outcomes measured in the trial but not reported on in this review: Migraine recurrence, nausea, vomiting, photophobia, phonophobia, functional impairment, use of rescue medication, treatment acceptability at 24 hours. |
|
| Notes | Patients were allowed to rescue with a second dose of study med if no response at 2 hours or for recurrence 2 to 24 hours after study start. Treated patients who were protocol violators were excluded from the analysis. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 0/129 Eletriptan 40 mg 2/99 Cafergot II tabs 2/68 Placebo 1/16 # patients reporting any AE: Eletriptan 80 mg 66/129 Eletriptan 40 mg 35/99 Cafergot II tabs 25/68 Placebo 8/16 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 5 parallel groups. Study drug self‐administered for single migraine attack of at least moderate intensity. Multi‐national (Europe and Australia). 24hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 0.5, 1, 1.5, 2, 4 and 24 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=548 Age 18‐71 | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Eletriptan 20 mg 4. Sumatriptan 100 mg 5. Placebo | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: headache response at 0.5 & 4 hours, pain‐free at 0.5, 1 & 4 hours. Other outcomes measured in the trial but not reported on in this review: photophobia, phonophobia, functional impairment, use of rescue medication, treatment acceptability and global impression at 24 hours. |
|
| Notes | Patients were allowed to rescue with a second dose of study med if no response at 2 hours or for recurrence 4 to 24 hours after study start. Protocol violators excluded from analysis, missing data treated as treatment failure. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 0/141 Eletriptan 40 mg 0/136 Eletriptan 20 mg 2/144 Sumatriptan 100 mg 1/129 Placebo 0/142 # patients reporting any AE: Eletriptan 80 mg 66/129 Eletriptan 40 mg 35/99 Eletriptan 20 mg 38/144 Sumatriptan 100 mg 37/129 Placebo 11/142 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 5 parallel groups. Study drug self‐administered for 3 migraine attack of at least moderate intensity. Multi‐national (Europe and Canada). 48hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 0.5, 1, 2, 4 and 24 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=773 Age 18‐76 | |
| Interventions | 1. Eletriptan 80 mg 2. Eletritpan 40 mg 3. Sumatriptan 100 mg 4. Sumatriptan 50 mg 5. Placebo | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: headache response at 0.5 hour, pain‐free at 0.5 & 1 hour. Other outcomes measured in the trial but not reported on in this review: photophobia, phonophobia, functional impairment, use of rescue medication, and quality of life questionnaire (SF36). |
|
| Notes | Patients were allowed to rescue with a second dose of study med if no response at 2 hours or for recurrence 2 to 24 hours after study start. Protocol violators excluded from analysis, missing data treated as treatment failure. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 1/105 Eletriptan 40 mg 2/106 Sumatriptan 50 mg 1/80 Sumatriptan 100 mg 1/80 Placebo 1/22 # patients reporting any AE: Eletriptan 80 mg 46/105 Eletriptan 40 mg 40/106 Sumatriptan 50 mg 17/80 Sumatriptan 100 mg 24/80 Placebo 4/22 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 5 parallel groups. Study drug self‐administered for up to 3 migraine attacks of at least moderate intensity. Multi‐centre (USA). 48hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 0.5, 1, 2, 4 and 24 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=818 Age 18‐65 | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Sumatriptan 50 mg 4. Sumatriptan 25 mg 5. Placebo | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: headache response at 0.5 hour, pain‐free at 0.5 & 1 hour. Other outcomes measured in the trial but not reported on in this review: photophobia, phonophobia, functional impairment, use of rescue medication, treatment acceptability at 24 hours and quality of life questionnaire (SF36). |
|
| Notes | Patients were allowed to rescue with a second dose of study med if no response at 2 hours or for recurrence 2 to 24 hours after study start. Protocol violators excluded from analysis, missing data treated as treatment failure. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 6/138 Eletriptan 40 mg 2/124 Sumatriptan 50 mg 2/99 Sumatriptan 100 mg 1/113 Placebo 0/42 # patients reporting any AE: Eletriptan 80 mg 58/138 Eletriptan 40 mg 33/124 Sumatriptan 50 mg 23/99 Sumatriptan 100 mg 23/113 Placebo 11/42 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 4 parallel groups. Study drug self‐administered for up to 3 migraine attacks of at least moderate intensity. Multi‐national (Europe, South Africa and Australia). 48hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 0.5, 1, 2, 4 and 24 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=1153 Age 18‐68 | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Placebo | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: headache response at 0.5 & 4 hours, pain‐free at 0.5, 1 & 4 hours. Other outcomes measured in the trial but not reported on in this review: photophobia, phonophobia, functional impairment, use of rescue medication, treatment acceptability at 24 hours and quality of life questionnaire (SF36). |
|
| Notes | Patients were allowed to rescue with a second dose of study med ifinsufficient response at 2 hours or for recurrence 2 to 24 hours after study start. Protocol violators excluded from analysis, missing data treated as treatment failure. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 2/219 Eletriptan 40 mg 6/225 Placebo 0/30 # patients reporting any AE: Eletriptan 80 mg 135/206 Eletriptan 40 mg 76/234 Placebo 50/205 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 4 parallel groups. Study drug self‐administered for up to 3 migraine attacks of at least moderate intensity. Multi‐centre (USA). 48hr washout for triptan or ergotamine, 6hr for analgesics or anti‐emetics prior to start. Evaluations made at 0, 0.5, 1, 2, 4 and 6 hours. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, Males and non‐pregnant females, n=1190 Age 18‐78 | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Eletriptan 20 mg 4. Placebo | |
| Outcomes | Major outcomes: headache response 1 & 2 hours, pain‐free at 2 hours, sustained relief over 24 hours. Minor outcomes: headache response at 0.5 & 4 hours, pain‐free at 0.5, 1 & 4 hours. Other outcomes measured in the trial but not reported on in this review: photophobia, phonophobia, functional impairment, use of rescue medication, treatment acceptability at 24 hours and quality of life questionnaire (SF36). |
|
| Notes | Patients were allowed to rescue with a second dose of study med ifinsufficient response at 4 hours or for recurrence 4 to 24 hours after study start. Protocol violators excluded from analysis, missing data treated as treatment failure. Adverse events for patients receiving one dose study med but includes non‐triptan rescue med. Treatment related AEs, measured over 0‐7 days using patient diary and investigator assessment. # patients reporting major AE (defined in the methods): Eletriptan 80 mg 11/208 Eletriptan 40 mg 1/167 Eletriptan 20 mg 1/142 Placebo 2/71 # patients reporting any AE: Eletriptan 80 mg 95/208 Eletriptan 40 mg 62/167 Eletriptan 20 mg 29/142 Placebo 19/71 qs=5 |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Low risk | A ‐ Adequate |
| Methods | RCT, DB, placebo‐controlled, multiple oral doses, 2 parallel groups. Study drug administered within 6 hours of migraine onset. | |
| Participants | Migraine with or without aura diagnosed according to IHS criteria, males and non‐pregnant females, aged 18 or older, n = 632 treated | |
| Interventions | 1. Eletriptan 80 mg 2. Eletriptan 40 mg 3. Placebo Complicated dosing schedule for first and second doses. |
|
| Outcomes | No outcomes data for the first attack treated. | |
| Notes | The data from this trial were not appropriate for inclusion in the efficacy analysis, but the data on adverse effects were included in the numbers‐needed‐to‐harm analysis. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment? | Unclear risk | D ‐ Not used |
AE = adverse effects qs = quality score RCT = randomised controlled trial DB = double blind IHS = International Headache Society # = number med = medication
Characteristics of excluded studies [ordered by study ID]
| Study | Reason for exclusion |
|---|---|
| Pfizer 1999g | No extractable data for the first attack treated (included, however, in the analysis of adverse effects). |
Sources of support
Internal sources
Pain Research Funds, UK.
External sources
Pfizer Ltd, UK.
International Headache Society (for administrative costs associated with editorial review and peer review), Not specified.
Declarations of interest
Cochrane systematic reviews of eletriptan and rizatriptan were prepared as part of a wider piece of work largely, but not entirely, funded by the manufacturer of eletriptan (Pfizer). The contract specified that all data on eletriptan (mostly unpublished) would be made available and that authors had freedom to publish results. The reviewers made their own choice about trials included or excluded and outcomes chosen or reported. Pain Research Unit resources were also used in the preparation of this review.
Co‐ordinating editor's comments: The code of conduct for the Cochrane Collaboration specifies that reviews should not be supported by direct funding from a single source with a vested interest in the results of a review. A decision to publish two systematic reviews (eletriptan and rizatriptan) was taken only after a great deal of discussion with a number of advisers, including the UK Cochrane Centre, and was made because the contract specified both that all data would be made available to reviewers and that the reviewers had the right to publish the results without restriction.
Notes
This review was withdrawn at the request of the Cochrane funding arbitration panel. There was no suggestion that the results of the review were mistaken, and it has been confirmed by other, subsequent, systematic reviews by other authors.
The review fulfilled the criteria required by The Cochrane Collaboration at the time of submission, and the source, nature, and terms of funding were discussed openly and fully. This funding included an absolute right to publish for the authors, with no interference from the funding source.
This review has now been replaced by a new published protocol: Derry S, Moore RA, McQuay HJ. Eletriptan for acute migraine headaches in adults (Protocol). Cochrane Database of Systematic Reviews 2010, Issue 4. Art. No.: CD008490. DOI: 10.1002/14651858.CD008490.
Withdrawn from publication for reasons stated in the review
References
References to studies included in this review
- Pfizer Inc. A double‐blind, randomised, placebo‐controlled, parallel‐group study of the efficacy and safety of eletriptan and Cafergot when given for the treatment of acute migraine. 1999. Data on file. Protocol 160‐307.
- Pfizer Inc. A multicenter, double‐blind, double‐dummy, parallel‐group, placebo‐controlled, dose‐response study of oral UK‐116,044 (eletriptan) and oral sumatriptan (100 mg) given for the acute treatment of migraine (with and without aura). 1999. Data on file. Protocol 160‐314.
- Pfizer Inc. A multicenter, double‐blind, double‐dummy, parallel‐group, placebo‐controlled study of two dose levels of oral eletriptan and two dose levels of oral sumatriptan given for the acute treatment of migraine. 1999. Data on file. Protocol 160‐318.
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