IT IS GIVEN BY CONTINUOUS INTRAVENOUS INFUSION OF A SOLUTION CONTAINING 50 TO 200 MICROGRAMS/ML. A CONTROLLED INFUSION DEVICE MUST BE USED. THE SOLUTION SHOULD BE PREPARED IMMEDIATELY BEFORE USE BY DISSOLVING SODIUM NITROPRUSSIDE IN GLUCOSE 5% AND THEN DILUTING WITH GLUCOSE 5%; THE SOLUTION MUST BE PROTECTED FROM LIGHT DURING ADMINISTRATION. BLOOD PRESSURE SHOULD BE MONITORED CLOSELY AND CARE SHOULD BE TAKEN TO PREVENT EXTRAVASATION. IN GENERAL, TREATMENT SHOULD NOT CONTINUE FOR MORE THAN 72 HOURS.
FOR HYPERTENSIVE CRISES IN PATIENTS NOT RECEIVING ANTIHYPERTENSIVE DRUGS, AN INITIAL DOSE OF 0.3 TO 1.5 MICROGRAMS/KG PER MINUTE MAY BE GIVEN, INCREASING GRADUALLY UNDER CLOSE SUPERVISION UNTIL THE DESIRED REDUCTION IN BLOOD PRESSURE IS ACHIEVED. THE AVERAGE DOSE REQUIRED TO MAINTAIN THE BLOOD PRESSURE 30 TO 40% BELOW THE PRETREATMENT DIASTOLIC BLOOD PRESSURE IS 3 MICROGRAMS/KG PER MINUTE AND THE USUAL DOSE RANGE IS 0.5 TO 6 MICROGRAMS/KG PER MINUTE. LOWER DOSES SHOULD BE USED IN PATIENTS ALREADY RECEIVING OTHER ANTIHYPERTENSIVES. THE MAXIMUM RECOMMENDED RATE IS ABOUT 8 MICROGRAMS/KG PER MINUTE IN THE UK, AND 10 MICROGRAMS/KG PER MINUTE IN THE USA; INFUSIONS AT THESE RATES SHOULD BE USED FOR NO LONGER THAN 10 MINUTES AND SHOULD BE STOPPED AFTER 10 MINUTES IF THERE IS NO RESPONSE. IF THERE IS A RESPONSE, SODIUM NITROPRUSSIDE SHOULD IDEALLY BE GIVEN FOR ONLY A FEW HOURS TO AVOID THE RISK OF CYANIDE TOXICITY. TREATMENT WITH AN ORAL ANTIHYPERTENSIVE SHOULD BE INTRODUCED AS SOON AS POSSIBLE.
FOR THE INDUCTION OF HYPOTENSION DURING ANAESTHESIA A MAXIMUM DOSE OF 1.5 MICROGRAMS/KG PER MINUTE IS RECOMMENDED.
IN HEART FAILURE AN INITIAL DOSE OF 10 TO 15 MICROGRAMS/MINUTE HAS BEEN USED, INCREASING BY 10 TO 15 MICROGRAMS/MINUTE EVERY 5 TO 10 MINUTES ACCORDING TO RESPONSE. THE USUAL DOSAGE RANGE IS 10 TO 200 MICROGRAMS/MINUTE AND THE DOSE SHOULD NOT EXCEED 280 MICROGRAMS/MINUTE (OR 4 MICROGRAMS/KG PER MINUTE).