Acetazolamide, usually sold under the trade name Diamox in some countries, is a carbonic anhydrase inhibitor that is used for the medical treatment of glaucoma, epileptic seizure, idiopathic intracranial hypertension, altitude sickness, cystinuria, periodic paralysis, central sleep apnea, and dural ectasia. Acetazolamide is a diuretic, and it is available as a generic drug in the United States. Diamox is now available as Diamox Sequels in the United States since the original product is no longer made or sold there. It is on the World Health Organization's List of Essential Medicines, a list of the most important medications needed in a basic health system.