THE USUAL DIAGNOSTIC PROCEDURE IS TO INJECT 2 MG INTRAVENOUSLY AND, IF NO ADVERSE REACTION OCCURS WITHIN 30 TO 45 SECONDS, TO CONTINUE WITH THE INJECTION OF A FURTHER 8 MG. IN THE UK THE RECOMMENDED TOTAL DOSE FOR CHILDREN IS 100 MICROGRAMS/KG, ONE-FIFTH OF THE DOSE BEING GIVEN INITIALLY, FOLLOWED 30 SECONDS LATER BY THE REMAINDER IF NO ADVERSE EFFECTS DEVELOP. IN THE USA A TOTAL DOSE OF 5 MG FOR CHILDREN WEIGHING LESS THAN 34 KG AND 10 MG FOR HEAVIER CHILDREN IS RECOMMENDED, WITH ONE-FIFTH OF THE DOSE BEING GIVEN INITIALLY FOLLOWED BY INCREMENTS OF 1 MG EVERY 30 TO 45 SECONDS; THE RECOMMENDED TOTAL DOSE FOR INFANTS IS 500 MICROGRAMS.
WHEN INTRAVENOUS INJECTION IS DIFFICULT EDROPHONIUM CHLORIDE MAY BE GIVEN BY INTRAMUSCULAR INJECTION; THE USUAL DOSE IN ADULTS IS 10 MG WHILE CHILDREN BELOW 34 KG IN WEIGHT MAY BE GIVEN 2 MG AND HEAVIER CHILDREN 5 MG; A SUGGESTED DOSE FOR INFANTS IS 0.5 TO 1 MG GIVEN INTRAMUSCULARLY OR SUBCUTANEOUSLY. ATROPINE SHOULD ALWAYS BE AVAILABLE WHEN THE TEST IS CARRIED OUT IN ORDER TO TREAT ANY SEVERE MUSCARINIC REACTIONS THAT MAY OCCUR.
TO DETECT UNDER- OR OVER-TREATMENT, TEST DOSES OF 1 TO 2 MG OF EDROPHONIUM CHLORIDE ARE GIVEN INTRAVENOUSLY TO DISTINGUISH SEVERE SYMPTOMS OF MYASTHENIA GRAVIS DUE TO INADEQUATE THERAPY FROM THE EFFECTS OF OVERDOSAGE WITH ANTICHOLINESTERASE DRUGS. IF TREATMENT HAS BEEN INADEQUATE, EDROPHONIUM CHLORIDE WILL PRODUCE AN IMMEDIATE AMELIORATION OF SYMPTOMS, WHEREAS IN CHOLINERGIC CRISES DUE TO OVER-TREATMENT THE SYMPTOMS WILL BE TEMPORARILY AGGRAVATED. IN THE UK, THE BNFC RECOMMENDS THAT EDROPHONIUM CHLORIDE MAY BE USED IN CHILDREN TO DETECT UNDER- OR OVER-TREATMENT IN A DOSE OF 20 MICROGRAMS/KG. LICENSED DRUG INFORMATION SUGGESTS TESTING ONE HOUR AFTER THE LAST DOSE OF TREATMENT BUT THE BNF AND THE BNFC RECOMMEND TESTING JUST BEFORE THE NEXT DOSE IS DUE. TESTING SHOULD ONLY BE UNDERTAKEN WHEN FACILITIES FOR ENDOTRACHEAL INTUBATION AND CONTROLLED VENTILATION ARE IMMEDIATELY AVAILABLE.
EDROPHONIUM CHLORIDE WAS ORIGINALLY INTRODUCED FOR THE REVERSAL OF NEUROMUSCULAR BLOCKADE IN ANAESTHESIA. IN THE UK, THE RECOMMENDED DOSE IN ADULTS AND CHILDREN FOR THE REVERSAL OF THE EFFECTS OF COMPETITIVE NEUROMUSCULAR BLOCKERS IS 500 TO 700 MICROGRAMS/KG GIVEN BY INTRAVENOUS INJECTION OVER SEVERAL MINUTES EITHER WITH OR AFTER ATROPINE SULFATE 7 MICROGRAMS/KG (TO A MAXIMUM OF 600 MICROGRAMS). IN THE USA, A DOSE OF 10 MG OF EDROPHONIUM CHLORIDE IS GIVEN OVER 30 TO 45 SECONDS AND REPEATED AS REQUIRED UP TO A MAXIMUM OF 40 MG. THE BREVITY OF ITS ACTION LIMITS ITS VALUE. WHERE PROLONGED APNOEA OCCURS IN A PATIENT TREATED WITH A DEPOLARISING NEUROMUSCULAR BLOCKER, SUCH AS SUXAMETHONIUM, EDROPHONIUM 10 MG MAY BE GIVEN INTRAVENOUSLY WITH ATROPINE TO DETERMINE THE PRESENCE OF PHASE II BLOCK .