THE USUAL INITIAL DOSE BY MOUTH FOR MUSCLE SPASM IS 1.5 G FOUR TIMES DAILY, REDUCED TO A MAINTENANCE DOSE OF ABOUT 4 G DAILY AFTER 2 TO 3 DAYS. A DOSE OF 750 MG THREE TIMES DAILY MAY BE SUFFICIENT FOR A THERAPEUTIC EFFECT. HALF THE MAXIMUM DAILY DOSE OR LESS MAY BE SUFFICIENT FOR ELDERLY PATIENTS.
IT HAS ALSO BEEN GIVEN INTRAVENOUSLY AT A RATE OF NOT MORE THAN 300 MG/MINUTE, BY SLOW INJECTION OR BY INFUSION IN SODIUM CHLORIDE 0.9% OR GLUCOSE 5% INJECTION. THE PARENTERAL ROUTE SHOULD NOT BE USED FOR MORE THAN 3 CONSECUTIVE DAYS AND THE DOSE SHOULD NOT EXCEED 3 G DAILY. THE PATIENT SHOULD REMAIN LYING DOWN DURING, AND FOR 10 TO 15 MINUTES AFTER, INTRAVENOUS DOSES. THE US MANUFACTURERS STATE THAT THE INJECTION IS HYPERTONIC AND EXTRAVASATION SHOULD BE AVOIDED. HOWEVER, IT MAY ALSO BE GIVEN BY INTRAMUSCULAR INJECTION IN A DOSE OF UP TO 500 MG INTO EACH GLUTEAL REGION AT INTERVALS OF 8 HOURS. CHILD NOT RECOMMENDED.