Intravenous acetylcysteine versus oral and intravenous acetylcysteine: Does a combination therapy decrease side effects of acetylcysteine?

Objective: acetylcysteine (nac) is the antidote for acetaminophen toxicity given by two routes (intravenous or orally). both routes have adverse side effects. we applied a new protocol using the combination therapy of both the oral and iv route for each patient and compared it with the only iv administration therapy regarding the outcome including anaphylactoid reactions. methodology: a randomized clinical trial study was performed on acetaminophen poisoning patients. the group a (iv group) was managed by initial bolus of iv nac with 150 mg/kg infused in 200cc of 5% dextrose in water within 30 minutes, followed by a 4 hour infusion of 50 mg/kg of nac in 500cc of 5%dw and finally with a 16 hour infusion of 100 mg/kg nac in 1000cc 5%dw. in group b (oral + iv group), initial nac 140 mg/ kg in 200cc of 5%dw was given orally. then the administration of nac was continued by iv route 50 mg/kg in 500cc of 5%dw in four hour infusion and then iv route, 100 mg/kg in 1000cc of 5%dw in 16 hour infusion. anaphylactoid and anaphylaxis reaction were compared between two groups. results: fifty patients were evaluated. anaphylactoid reaction was observed in 60.7% and 13.3% in a and b group respectively (p value, 0.004). there was a significant relationship between the anaphylactoid reactions and the route of nac administration (p value, 0.001; r, 0.47). conclusion: less anaphylactoid reactions may be observed in patients who receive combination of oral and intravenous acetylcysteine than the iv administration therapy.