FOR PREMEDICATION 300 TO 600 MICROGRAMS OF ATROPINE SULFATE MAY BE GIVEN BY SUBCUTANEOUS OR INTRAMUSCULAR INJECTION, USUALLY 30 TO 60 MINUTES BEFORE ANAESTHESIA. ALTERNATIVELY 300 TO 600 MICROGRAMS OF ATROPINE SULFATE MAY BE GIVEN INTRAVENOUSLY IMMEDIATELY BEFORE INDUCTION OF ANAESTHESIA. SUITABLE PAEDIATRIC SUBCUTANEOUS OR INTRAMUSCULAR PREMEDICATION DOSES OF ATROPINE SULFATE ARE:
CHILDREN UP TO 3 KG IN WEIGHT: 100 MICROGRAMS
CHILDREN 7 TO 9 KG IN WEIGHT: 200 MICROGRAMS
CHILDREN 12 TO 16 KG IN WEIGHT: 300 MICROGRAMS
CHILDREN OVER 20 KG IN WEIGHT: THE ADULT DOSE.
FOR INTRA-OPERATIVE BRADYCARDIA THE BNF STATES THAT 300 TO 600 MICROGRAMS MAY BE GIVEN INTRAVENOUSLY; LARGER DOSES MAY BE USED IN EMERGENCIES. CHILDREN MAY BE GIVEN 10 TO 20 MICROGRAMS/KG.
TO COUNTERACT THE MUSCARINIC EFFECTS OF ANTICHOLINESTERASES WHEN THEY ARE USED TO REVERSE THE EFFECTS OF COMPETITIVE MUSCLE RELAXANTS ADULTS ARE GIVEN ATROPINE SULFATE 0.6 TO 1.2 MG BY INTRAVENOUS INJECTION BEFORE OR WITH THE ANTICHOLINESTERASE. NEONATES, INFANTS, AND CHILDREN MAY BE GIVEN A DOSE OF 20 MICROGRAMS/KG.
FOR ADVANCED LIFE SUPPORT IN ADULTS WITH ASYSTOLE OR ELECTROMECHANICAL DISSOCIATION, EUROPEAN AND UK GUIDELINES RECOMMEND ATROPINE IN A SINGLE DOSE OF 3 MG INTRAVENOUSLY; US GUIDELINES RECOMMEND REPEATED DOSES OF 1 MG TO A TOTAL MAXIMUM DOSE OF 3 MG.
IN BRADYCARDIA, ATROPINE IS GIVEN IN DOSES OF 500 MICROGRAMS INTRAVENOUSLY REPEATED EVERY 3 TO 5 MINUTES TO A TOTAL DOSE OF 3 MG.
IF AN INTRAVENOUS LINE CANNOT BE ESTABLISHED, ATROPINE CAN BE GIVEN VIA AN ENDOTRACHEAL TUBE; 2 TO 3 TIMES THE INTRAVENOUS DOSE SHOULD BE GIVEN, DILUTED IN 10 ML OF STERILE WATER OR SODIUM CHLORIDE 0.9%.
IN THE TREATMENT OF INFLAMMATORY EYE DISORDERS SUCH AS UVEITIS OR IRIT, THE DOSE OF ATROPINE SULFATE FOR ADULTS IS 1 OR 2 DROPS OF A 0.5 OR 1% SOLUTION INSTILLED INTO THE EYE(S) UP TO FOUR TIMES DAILY. THE DOSE IN CHILDREN IS 1 OR 2 DROPS OF A 0.5% SOLUTION (OR ONE DROP OF A 1% SOLUTION) INSTILLED UP TO THREE TIMES DAILY. FOR REFRACTION IN ADULTS THE DOSE IS ONE DROP OF A 1% SOLUTION OF ATROPINE SULFATE; THIS MAY BE INSTILLED EITHER TWICE DAILY FOR 1 OR 2 DAYS BEFORE THE PROCEDURE OR ON A SINGLE OCCASION ONE HOUR BEFORE THE PROCEDURE. IN CHILDREN THE DOSE FOR REFRACTION IS 1 OR 2 DROPS OF A 0.5% SOLUTION (OR ONE DROP OF A 1% SOLUTION) INSTILLED TWICE DAILY FOR 1 TO 3 DAYS BEFORE THE PROCEDURE, WITH A FURTHER DOSE GIVEN ONE HOUR BEFORE THE PROCEDURE. AN OPHTHALMIC OINTMENT OF ATROPINE SULFATE 1% MAY BE PREFERRED FOR CHILDREN UNDER 5 YEARS AND PARTICULARLY IN INFANTS UNDER 3 MONTHS WHO ARE AT INCREASED RISK OF SYSTEMIC EFFECTS WITH EYE DROPS. SOME MANUFACTURERS RECOMMEND THAT ATROPINE SULFATE SHOULD NOT BE USED IN THE EYES OF CHILDREN YOUNGER THAN 3 MONTHS DUE TO A POSSIBLE ASSOCIATION BETWEEN THE CYCLOPLEGIA PRODUCED AND THE DEVELOPMENT OF AMBLYOPIA.
ANTIMUSCARINICS MAY BE USED IN GASTROINTESTINAL DISORDERS AS ANTISPASMODICS BECAUSE OF THEIR MARKED INHIBITORY EFFECT ON GASTROINTESTINAL MOTILITY, AND FOR THEIR ANTISECRETORY EFFECTS. ATROPINE (AS THE SULFATE OR QUATERNARY DERIVATIVES SUCH AS THE METHOBROMIDE OR METHONITRATE) HAS BEEN USED TO REDUCE SMOOTH-MUSCLE TONE AND DIMINISH MOTILITY, BUT HAS LITTLE EFFECT ON GASTRIC SECRETION AT USUAL THERAPEUTIC DOSES (ABOUT 200 MICROGRAMS OF ATROPINE SULFATE). IT HAS BEEN TRIED AS AN ADJUNCT TO THE TREATMENT OF BENIGN GASTRIC AND DUODENAL ULCERS AND THE ANTISPASMODIC ACTION OF ATROPINE HAS BEEN USED TO FACILITATE RADIOLOGICAL EXAMINATION OF THE GUT. ATROPINE SULFATE HAS ALSO BEEN USED IN THE TREATMENT OF IRRITABLE BOWEL SYNDROME. ATROPINE OXIDE HYDROCHLORIDE IS ALSO USED FOR GASTROINTESTINAL DISORDERS.
ATROPINE IS USED IN THE MANAGEMENT OF OVERDOSAGE OR POISONING DUE TO ANTICHOLINESTERASE COMPOUNDS INCLUDING ORGANOPHOSPHORUS PESTICIDES, CHEMICAL WARFARE NERVE GASES, AND PARASYMPATHOMIMETICS SUCH AS NEOSTIGMINE. IT IS ALSO USED TO ANTAGONISE THE EFFECTS OF CHOLINOMIMETIC SUBSTANCES IN THE TREATMENT OF OVERDOSAGE WITH PARASYMPATHOMIMETICS SUCH AS BETHANECHOL, AND IN THE TREATMENT OF POISONING WITH MUSHROOMS THAT CONTAIN MUSCARINE. ATROPINE BLOCKS THE ACTION OF THESE COMPOUNDS AT MUSCARINIC RECEPTORS, REVERSING BRADYCARDIA AND DECREASING TRACHEOBRONCHIAL SECRETIONS, BRONCHOCONSTRICTION, INTESTINAL SECRETIONS, AND INTESTINAL MOTILITY.
IN THE TREATMENT OF POISONING WITH ORGANOPHOSPHORUS PESTICIDES OR CHEMICAL WARFARE NERVE GASES ATROPINE SULFATE MAY BE GIVEN TO ADULTS IN AN INITIAL DOSE OF 2 MG INTRAMUSCULARLY OR INTRAVENOUSLY EVERY 10 TO 30 MINUTES UNTIL MUSCARINIC EFFECTS DISAPPEAR OR SIGNS OF ATROPINE TOXICITY ARE SEEN. IN SEVERE CASES INJECTIONS HAVE BEEN GIVEN AS OFTEN AS EVERY 5 MINUTES IN SOME CENTRES. CONTINUOUS INFUSION HAS ALSO BEEN USED. A DOSE OF AT LEAST 50 MICROGRAMS/KG HAS BEEN SUGGESTED FOR CHILDREN BY SOME; THE BNF INCLUDES A DOSE OF 20 MICROGRAMS/KG GIVEN EVERY 5 TO 10 MINUTES.
IN MODERATE TO SEVERE POISONING A STATE OF ATROPINISATION IS USUALLY MAINTAINED FOR AT LEAST 2 DAYS AND CONTINUED FOR AS LONG AS SYMPTOMS ARE EVIDENT. IN SEVERELY POISONED PATIENTS THIS MAY ENTAIL PROLONGED TREATMENT. AS LARGE AMOUNTS OF ATROPINE MAY BE REQUIRED IT IS IMPORTANT TO USE A PRESERVATIVE-FREE PREPARATION TO AVOID THE POTENTIAL TOXICITY ASSOCIATED WITH USE OF EXCESS QUANTITIES OF PRESERVATIVES SUCH AS BENZYL ALCOHOL OR CHLOROBUTANOL.
SINCE ATROPINE IS INEFFECTIVE AGAINST ANY NICOTINIC EFFECTS OF THESE COMPOUNDS A CHOLINESTERASE REACTIVATOR SUCH AS PRALIDOXIME MAY BE USED AS AN ADJUNCT.
THE USE OF ATROPINE IN POISONING OR OVERDOSAGE WITH OTHER COMPOUNDS HAVING MUSCARINIC ACTIONS IS SIMILAR TO THAT FOR ORGANOPHOSPHORUS PESTICIDES BUT THE DURATION OF TREATMENT NECESSARY IS USUALLY SHORTER. AN INITIAL DOSE OF 0.6 TO 1 MG GIVEN SUBCUTANEOUSLY, INTRAMUSCULARLY, OR INTRAVENOUSLY AND REPEATED EVERY 2 HOURS MAY BE ADEQUATE FOR OVERDOSAGE WITH CHOLINOMIMETICS SUCH AS BETHANECHOL.