IV Mucomyst =========== þ Risks - If given over 15 minutes, can have anaphylactoid reaction, so given over an hour - PO solution, filtered through 0.22 micron filter þ When to give IV: - Pregnancy - Inability to take PO - Liver failure þ Timing: - No outcome difference if given any time in first 8 hours - May want to give one dose empirically if waiting will put you over the 8-hour limit Intravenous NAC is still in the investigational stage of use in the U.S. although it has been widely used in Europe for years (European Prescott Protocol). Until FDA approval has been obtained for using the oral form as an IV drug it is advisable to consider IV NAC only in cases that involve patients unable to tolerate the oral form (most commonly due to intractable vomiting refractory to IV metoclopramide or ondansetron) or some late-presenting patients. It is always advisable to contact your Poison Center for guidance on the IV protocols, advantages and disadvantages, medico-legal risks (informed consent) etc. Until proven "pyrogen-free" to the FDA, a micropore filter is always recommended. Common side effects are itching and rash. Hmmm, itchy rash or liver transplant? Refs: Smilkstein MJ et al. Acetaminophen overdose: a 48-hour intravenous N-acetylcysteine protocol. Ann Emerg Med 20(10):1058-1063, 1993. Prescott LF. Treatment of severe acetaminophen poisoning with intravenous acetylcysteine. Arch Int Med 141(3 Spec No):386-389, 1981. Chan TY, Critchley JA. Adverse reactions to intravenous N-acetylcysteine in Chinese patients with paracetamol (acetaminophen) poisoning. Human & Experimental Toxicology. 13(8):542-4,1994 Aug. Miguel C. Fernandez, MD, FACEP Arizona Health Sciences Center Emergency Medicine/Toxicology AZ Poison & Drug Info Center University of Arizona Tucson, AZ 85724-5057 ----------------------- Australian dosing: Loading dose 150 mg/kg over 15 min then, 50 mg/kg over 4 hours then, 100 mg/kg over 16 hours Patients quite frequently get a mild rash +/- a degree of bronchospasm in the early stages of the 4 hour infusion. About six months ago we had five patients in a row become quite distressed by wheezing and rash. All recovered with symptomatic and empirical treatment and were able to tolerate the gradual reintroduction of the infusion. They all got Parvolex from the same batch (not out of date but close) and the problem went away with a change of batch. Coincidence mabye? Need for filters perhaps? Dr Garry Wilkes MBBS FACEM Department of Emergency Medicine Royal Brisbane Hospital Queensland, Australia Email G.Wilkes@mailbox.uq.edu.au Canadian Dosing: Of course here it's approved, but we always use IV form. We use the short IV protocol (20 hours) for intox less than 10 hours ago, and the long protocol (48 hours) for intox more than 10 hours ago. Short IV protocol consist of weight ajusted dose as a bolus (which is given more in 30 minutes than proposed 15 minutes because, on the advice of our poison center expert, it give less reaction that way), then a weight adjusted 4 hours perfusion, then a weight ajusted 16 hours perfusion. (Well, we should call it a 20h30 protocol). Long IV protocol is a bolused standard Mucomyst solution of 0.7 cc/kg over 30 minutes and then .35 cc/kg over 30 minutes each 4 hours for 17 doses (quite similar to US PO regimen). All the stuff is diluted in D5%. Alain Vadeboncoeur MD CH Pierre-Boucher Longueuil, Quebec