A controlled release pharmaceutical tablet is disclosed which is based on: (a) a compressed core which contains: i) a medicament; ii) from 5 to 20 % by weight of a water soluble osmotic agent based on the total weight of the compressed core; iii) a water soluble pharmaceutically acceptable polymeric binder; iv) a conventional pharmaceutical excipient; and (b) a dual layer membrane coating around said core which consists essentially of: i) a first inner coating layer for sustained release of the medicament, said inner coating layer consisting essentially of a plasticized water insoluble pharmaceutically acceptable polymer and a pharmaceutically acceptable water soluble polymer, and; ii) a second outer coating layer for immediate release of a medicament, said outer coating layer consisting essentially of an effective amount of a medicament and a water soluble polymer. The controlled release formulation is suitable for the once-a-day administration of medicaments.