Duchenne muscular dystrophy is a progressive wasting condition of muscles which starts in early childhood, leads to dependence on a wheelchair by the age of thirteen and respiratory failure by late teens. The condition is due to absence of dystrophin, a large muscle protein that has several functions within muscle cells. We know that calcium molecules build up in the muscle cells of people with Duchenne muscular dystrophy and this is associated with cell death. The rationale behind this review was to ascertain whether randomised controlled trials using drugs that block calcium entry into muscle would result in a reduction in progression of the condition. Although these trials were conducted over ten years ago a systematic review was not done at that time, and so a potential effect of calcium blocking drugs (antagonists) on the course of DMD may have been missed. If it were to exist, calcium antagonists might be an effective treatment in their own right or, more likely, could be used in combination with newer treatments such as corticosteroids or potential treatments such as gene related therapies.
This is an updated review. In the original review original eight studies were identified and five were high enough quality to be included. In this update no new trials were identified and so five were still included in the review. These studies were of different types of calcium channel blocking drugs and measured a variety of outcomes such as muscle strength, scales of muscle function, biochemical changes in muscle and electrocardiographic findings. Only one study showed a beneficial effect, which was an increase in muscle strength, but in this study the drug used was also associated with cardiac side effects. Adverse effects noted were mostly known side effects of calcium channel blockers.
Limitations of the review were that a meta-analysis could not be done as the trials used different calcium channel blockers and measured different outcomes, and all but one of the trials included a low number of patients. In conclusion, the review did not find calcium antagonists to have a useful effect.