The acylurea functional group is also found in some pharmaceutical drugs such as the anticonvulsants phenacemide, pheneturide, chlorphenacemide, and acetylpheneturide (which are phenylureides), and the sedatives acecarbromal, bromisoval, and carbromal (which are bromoureides). Others include apronal (apronalide), capuride, and ectylurea. Barbiturates (a class of cyclic ureas) are structurally and mechanistically related to them. The phenylureides are also closely related to the hydantoins, such as phenytoin, and may be considered ring-opened analogues of them.