Dofetilide/Dofetilidum CAS115256-11-6 is a class III antiarrhythmic agent. It is marketed under the trade name Tikosyn by Pfizer, and is available in the United States in capsules containing 125, 250, and 500 µg of dofetilide. Dofetilide/ Dofetilidum is not available in Europe or Australia. Due to the pro-arrhythmic potential of dofetilide, it is only available by prescription from physicians who have undergone specific training in the risks of treatment with dofetilide. In addition, it is only available by mail order or through specially trained local pharmacies.