| Methods |
Randomised, double‐blind, placebo‐controlled, cross‐over study |
| Participants |
3 adults with McArdle disease (2 men and 1 woman, aged 26, 44 and 24 years) and 8 people with an exertional muscle pain syndrome (6 men and 2 women, aged 19 to 40 years) |
| Interventions |
80 mg verapamil once daily for 3 days, twice daily for 4 days then 3 times daily for 5 weeks. After 6 weeks all participants stopped treatment for 2 weeks and then crossed over to the alternative treatment |
| Outcomes |
Pain diary which recorded the severity of muscle pain on a scale of 0 to 10, the amount of time spent reclining, sleeping, sitting and standing/ walking/ running for the same three hour period each day for 14 weeks, timed exercise test |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
The method of sequence generation was not described |
| Allocation concealment (selection bias) |
Unclear risk |
The method of allocation concealment was not described |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Both participants and observers were blinded |
| Incomplete outcome data (attrition bias)
All outcomes |
High risk |
None of the McArdle participants kept satisfactory diaries |
| Selective reporting (reporting bias) |
High risk |
None of the McArdle participants kept adequate diaries |
| Other bias |
Low risk |
No other source of bias identified |
