HYOSCINE IS A TERTIARY AMINE ANTIMUSCARINIC WITH CENTRAL AND PERIPHERAL ACTIONS .IT IS A MORE POWERFUL SUPPRESSANT OF SALIVATION THAN ATROPINE, AND USUALLY SLOWS RATHER THAN INCREASES HEART RATE, ESPECIALLY IN LOW DOSES. ITS CENTRAL ACTION DIFFERS FROM THAT OF ATROPINE IN THAT IT DEPRESSES THE CEREBRAL CORTEX AND PRODUCES DROWSINESS AND AMNESIA. HYOSCINE HYDROBROMIDE IS ALSO A TERTIARY AMINE, WHEREAS HYOSCINE BUTYLBROMIDE, HYOSCINE METHOBROMIDE, AND HYOSCINE METHONITRATE ARE QUATERNARY AMMONIUM DERIVATIVES.
HYOSCINE AND HYOSCINE HYDROBROMIDE ARE USED IN THE MANAGEMENT OF MOTION SICKNESS AND OTHER FORMS OF NAUSEA AND VOMITING; HYOSCINE HYDROBROMIDE IS ALSO GIVEN AS A PREMEDICANT IN ANAESTHESIA, AND TO PRODUCE MYDRIASIS AND CYCLOPLEGIA. HYOSCINE BUTYLBROMIDE AND OTHER QUATERNARY AMMONIUM DERIVATIVES ARE USED IN CONDITIONS ASSOCIATED WITH VISCERAL SPASMS. IN ADDITION, HYOSCINE METHOBROMIDE HAS BEEN EMPLOYED AS AN ADJUNCT IN THE TREATMENT OF PEPTIC ULCER DISEASE.