BACLOFEN IS GIVEN BY MOUTH IN DIVIDED DOSES, PREFERABLY WITH OR AFTER FOOD OR MILK. THE INITIAL DOSE OF BACLOFEN IS 5 MG THREE TIMES DAILY FOR 3 DAYS, INCREASED TO 10 MG THREE TIMES DAILY FOR 3 DAYS, THEN IN SIMILAR INCREMENTS AND INTERVALS UNTIL EITHER A DOSE OF 20 MG THREE TIMES DAILY IS REACHED OR UNTIL THE DESIRED THERAPEUTIC EFFECT IS OBTAINED. HIGHER DOSES HAVE BEEN USED. DOSES OF MORE THAN 80 TO 100 MG DAILY ARE NOT GENERALLY RECOMMENDED ALTHOUGH DOSES OF UP TO 150 MG DAILY HAVE BEEN GIVEN TO CAREFULLY SUPERVISED PATIENTS.
IN THE UK A DOSAGE RANGE OF 0.75 TO 2 MG/KG DAILY HAS BEEN USED FOR CHILDREN; IN CHILDREN OVER 10 YEARS A MAXIMUM DAILY DOSAGE OF 2.5 MG/KG MAY BE GIVEN. IT IS USUAL TO START WITH A LOW DOSE OF 2.5 MG GIVEN FOUR TIMES DAILY, INCREASED CAUTIOUSLY ABOUT EVERY 3 DAYS UNTIL THE DESIRED THERAPEUTIC EFFECT IS OBTAINED. THE RECOMMENDED DAILY MAINTENANCE DOSES ARE: 12 MONTHS TO 2 YEARS, 10 TO 20 MG; 2 TO 6 YEARS, 20 TO 30 MG; 6 TO 10 YEARS, 30 TO 60 MG.
ELDERLY PATIENTS SHOULD RECEIVE LOWER INITIAL DOSES, ALTHOUGH FINAL MAINTENANCE DOSES MAY BE IN THE SAME RANGE AS YOUNGER ADULTS. FOR DOSAGE IN RENAL IMPAIRMENT.
IF NO BENEFIT IS APPARENT WITHIN 6 WEEKS OF ACHIEVING THE MAXIMUM DOSAGE, THERAPY SHOULD PROBABLY BE GRADUALLY WITHDRAWN.
BACLOFEN IS ALSO GIVEN BY CONTINUOUS INTRATHECAL INFUSION IN THE TREATMENT OF SPASTICITY IN PATIENTS INTOLERANT OF, OR UNRESPONSIVE TO, BACLOFEN BY MOUTH. BEFORE BEGINNING THE INTRATHECAL REGIMEN ANY EXISTING ANTISPASTIC THERAPY SHOULD BE GRADUALLY WITHDRAWN TO AVOID OVERDOSAGE OR DRUG INTERACTIONS. INTRATHECAL TEST DOSES ARE GIVEN INITIALLY TO DETERMINE IF THERE IS GOING TO BE ANY BENEFIT BEFORE IMPLANTING A CONTROLLED INFUSION PUMP. IT IS IMPORTANT THAT PATIENTS ARE MONITORED CLOSELY IN EXPERIENCED CENTRES DURING SCREENING AND IMMEDIATELY AFTER IMPLANTATION OF THE INFUSION PUMP AND THAT RESUSCITATION EQUIPMENT IS AVAILABLE FOR IMMEDIATE USE.
TEST DOSES START AT 25 OR 50 MICROGRAMS GIVEN OVER AT LEAST 1 MINUTE AND ARE INCREASED BY 25 MICROGRAMS EVERY 24 HOURS UNTIL A DOSE OF 100 MICROGRAMS IS REACHED OR A POSITIVE RESPONSE OF ABOUT 4 TO 8 HOURS IS OBTAINED. PATIENTS WHO FAIL TO RESPOND TO A TEST DOSE OF UP TO 100 MICROGRAMS ARE CONSIDERED TO BE UNSUITABLE FOR INTRATHECAL TREATMENT. FOR CHILDREN AGED 4 TO 18 YEARS WITH SPASTICITY OF CEREBRAL ORIGIN AN INITIAL TEST DOSE OF 25 MICROGRAMS IS RECOMMENDED. HOWEVER, THE MANUFACTURERS DO NOT RECOMMEND THE USE OF INTRATHECAL BACLOFEN IN PATIENTS IN THIS AGE GROUP WITH SPASTICITY OF SPINAL ORIGIN.
FOR PATIENTS SHOWING A POSITIVE RESPONSE LASTING FOR LONGER THAN 8 TO 12 HOURS, THE TEST DOSE THAT WAS REQUIRED TO PRODUCE THE RESPONSE CAN THEN BE GIVEN AS A 24-HOUR INFUSION; IF THE RESPONSE TO THE TEST DOSE LASTED 8 TO 12 HOURS OR LESS, THEN A DOSE EQUIVALENT TO TWICE THE TEST DOSE IS GIVEN. DAILY DOSAGE CAN THEN BE ADJUSTED AS REQUIRED. MAINTENANCE DOSES RANGE FROM ABOUT 10 MICROGRAMS TO 2 MG DAILY, DEPENDING ON THE CAUSE OF SPASTICITY, WITH MOST PATIENTS BEING ADEQUATELY MAINTAINED WITH 300 TO 800 MICROGRAMS DAILY.