IN HYPERTENSION LABETALOL HYDROCHLORIDE IS USUALLY GIVEN IN AN INITIAL DOSE OF 100 MG TWICE DAILY BY MOUTH WITH FOOD, GRADUALLY INCREASED IF NECESSARY ACCORDING TO RESPONSE AND STANDING BLOOD PRESSURE, TO 200 TO 400 MG TWICE DAILY; TOTAL DAILY DOSES OF 2.4 G, IN TWO TO FOUR DIVIDED DOSES, HAVE OCCASIONALLY BEEN REQUIRED. AN INITIAL DOSE OF 50 MG TWICE DAILY HAS BEEN RECOMMENDED FOR ELDERLY PATIENTS.
FOR THE EMERGENCY TREATMENT OF HYPERTENSION LABETALOL HYDROCHLORIDE MAY BE GIVEN BY SLOW INTRAVENOUS INJECTION. IN THE UK A DOSE OF 50 MG IS RECOMMENDED, GIVEN OVER A PERIOD OF AT LEAST 1 MINUTE; IF NECESSARY THIS DOSE MAY BE REPEATED AT INTERVALS OF 5 MINUTES UNTIL A TOTAL OF 200 MG HAS BEEN GIVEN. IN THE USA AN INITIAL DOSE OF 20 MG IS RECOMMENDED, GIVEN OVER 2 MINUTES; SUBSEQUENT DOSES OF 40 TO 80 MG MAY BE GIVEN EVERY 10 MINUTES, IF NECESSARY, UP TO A MAXIMUM OF 300 MG. BLOOD PRESSURE SHOULD BE MONITORED, AND THE PATIENT SHOULD REMAIN SUPINE DURING INTRAVENOUS ADMINISTRATION AND FOR 3 HOURS AFTERWARDS, TO AVOID EXCESSIVE ORTHOSTATIC HYPOTENSION. AFTER BOLUS INTRAVENOUS INJECTION A MAXIMUM EFFECT IS USUALLY OBTAINED WITHIN 5 MINUTES AND USUALLY LASTS UP TO 6 HOURS, ALTHOUGH IT MAY EXTEND AS LONG AS 18 HOURS.
LABETALOL HYDROCHLORIDE HAS ALSO BEEN GIVEN BY INTRAVENOUS INFUSION IN USUAL DOSES OF 2 MG/MINUTE. SUGGESTED CONCENTRATIONS FOR INTRAVENOUS INFUSIONS ARE 1 MG/ML OR 2 MG/3 ML OF SUITABLE DILUENT. IN HYPERTENSION IN PREGNANCY, LABETALOL INFUSION MAY BE STARTED AT THE RATE OF 20 MG/HOUR, THEN DOUBLED EVERY 30 MINUTES UNTIL A SATISFACTORY RESPONSE IS OBTAINED OR A DOSE OF 160 MG/HOUR IS REACHED. IN HYPERTENSION AFTER MYOCARDIAL INFARCTION, LABETALOL INFUSION MAY BE STARTED AT THE RATE OF 15 MG/HOUR AND GRADUALLY INCREASED UNTIL A SATISFACTORY RESPONSE IS OBTAINED OR A DOSE OF 120 MG/HOUR IS REACHED.
THE INITIAL DOSE IN HYPOTENSIVE ANAESTHESIA IS 10 TO 20 MG INTRAVENOUSLY, WITH INCREMENTS OF 5 TO 10 MG IF SATISFACTORY HYPOTENSION IS NOT ACHIEVED AFTER 5 MINUTES. A HIGHER INITIAL DOSE MAY BE REQUIRED IN PATIENTS WHO DO NOT RECEIVE HALOTHANE ANAESTHESIA.
CHILDREN :- NOT RECOMMENDED.