Table 2.

Characteristics of included studies.

Author, year	Headache type, setting	N	Opioid Dose	Administered with opioid	Comparator	Administered with comparator	Time to primary outcome	Jadad score	Primary Outcome used
Cicek, 2004	Vascular headache, ED	99	Pethidine 50mg IM	None	Metoclopramide 10mg IV	None	60 min.	4	Rescue med
Richman, 2002	IHS migraine, ED	29	Meperidine 1.5mg/kg IM	None	Droperidol 2.5mg IM	None	30 min.	2	Rescue med
Carleton, 1998	Vascular headache, ED	156	Meperidine 1.5mg/kg IM	Hydroxyzine 0.7mg/kg IM	DHE 1mg IM	Hydroxyzine 0.7mg/kg IM	60 min.	5	Headache relief
Davis, 1995	EP diagnosed migraine, ED	42	Meperidine 75mg IM	Promethazine 25mg IM	Ketorolac 60mg IM	None	60 min.	5	Headache relief
Scherl, 1995	Migraine criteria, clinic	27	Meperidine 75mg IM	Promethazine IM	DHE 0.5mg IV	Metoclopramide	60 min	3	SMD change pain score
Klapper, 1993	Physician diagnosed migraine, clinic	28	Meperidine 75mg IM	Hydroxyzine 75mg IM	DHE 1mg IV	Metoclopramide 10mg IV	60 min.	2	Headache relief
Larkin, 1992	EP diagnosed migraine, ED	31	Meperidine 75mg IM	None	Ketorolac 30mg IM	None	60 min.	5	Headache relief
Duarte, 1992	IHS migraine, ED	50	Meperidine 100mg IM	Hydroxyzine 50mg IM	Ketorolac 60mg IM	None	60 min.	4	Headache relief
Stiell, 1991	Migraine score, ED	74	Meperidine 75mg IM	Dimenhydrinate 50mg IM	Methotrimeprazine 37.5mg IM	None	60 min.	5	Rescue med
Belgrade, 1989	Migraine score, ED	43*	1)Meperidine 75mg IM	1)Hydroxyzine 50mg IM	DHE 1mg IV	Metoclopramide 1mg IV	30 min.	2	SMD VAS change
			2) Butorphanol 2mg IM	2)None
Lane, 1989	EP diagnosed migraine, ED	46	Meperidine 0.4 mg/kg x 3 doses	Dimenhydrinate 25mg	Chlorpromazine 0.1 mg/kg	None	60 min.	3	Headache relief

Notes: N=total number of patients included in the primary efficacy analysis; EP= emergency physician; ED = emergency department; Rescue med = Requirement of rescue medication for persistent headache; IHS= International Headache Society’s International Classification of Headache Disorders; DHE = dihydroergotamine; SMD = standardized mean difference. Jadad score is a five point scale that measures methodological quality by assessing features such as method of randomization and allocation concealment. Scores above two are generally considered to represent higher quality studies.

^*In the Belgrade study, 22 patients received meperidine, 21 received DHE, and 19 received butorphanol