Dirythmin SA contains the medicine disopyramide phosphate. It is a member of a group of medicines called class 1A (the name of a specific group of drugs) antiarrhythmics.

Dirythmin SA is used to treat disorders of the heart rhythm (arrhythmias), where the heart does not beat regularly. It is particularly useful in treating arrhythmias when the chambers of the heart, called the atria and ventricles, beat irregularly.

Dirythmin SA acts by slowing down electrical impulses in the heart which control the heart rhythm, making it beat more slowly and regularly.

Dirythmin SA is supplied as tablets. It is important to take this medicine to control heart rhythm even if you don't feel ill, and not to stop it unless advised by your doctor.