Prateepavanich 1999.
| Methods | Single‐blind, parallel group RCT, set in Thailand | |
| Participants | 24 adult outpatients (mean age 64 years) with nocturnal calf cramps associated with myofascial pain syndrome and gastrocnemius trigger points with at least 4 cramps per month | |
| Interventions | Quinine sulphate 300 mg orally daily at bedtime or 1 to 2 ml 1% xylocaine injection at the gastrocnemius trigger point at the start of the trial. Treatment period for 4 weeks, followed by follow‐up 4 weeks later. All subjects assigned to perform calf stretches daily | |
| Outcomes | Cramp number, cramp intensity (graded 0 = no pain to 10 = severe), cramp duration (minutes), adverse events | |
| Notes | Participants recruited from several outpatient clinics in Thailand. 2 participants withdrew from the study due to cinchonism during the treatment period. 20 of the 22 participants who completed the study were women | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "They were randomly divided into two groups..." Comment: no description of randomisation protocol |
| Allocation concealment (selection bias) | Unclear risk | No details regarding how allocation may have been concealed is given |
| Blinding (performance bias and detection bias) All outcomes | High risk | Quote: "...a single‐blinded comparative clinical study." Comment: no control group was used for the injection treatment. The reviewing physician was blinded to the treatment received by the participants |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Reasons for the 2 participant withdrawals are given but these were not counted in an intention‐to‐treat analysis |
| Selective reporting (reporting bias) | Low risk | All intended outcome measures were addressed |
| Other bias | High risk | The number of treatments received by participants in the injection group varied depending on individual cramp frequencies during the follow‐up period; there was therefore no uniform dose/regimen for the injections. Significant confounder in the fact that all participants were to perform calf stretches daily |