Until recently in the United States, the intravenous (IV) administration of N-acetylcysteine (NAC) in acetaminophen (APAP) poisonings was reserved for patients unable to take or tolerate oral NAC. Aside from these situations, oral administration of NAC was preferred. In February 2004 an IV formulation of NAC, Acetadote, was approved by the US Food and Drug Administration. This study was designed to examine the influence of Acetadote availability on the use of IV NAC in the treatment of APAP poisonings.Methods:
A retrospective review of poison center records was performed for cases reported to a poison control system 6 months before (PRE) and 6 months after (POST) the release of Acetadote. Extracted variables included patient age and sex, reason for exposure, type of APAP product involved, exposure duration, rationale for use of IV NAC, reported adverse reactions, medical outcomes, and source of IV. Also, the average wholesale price for Acetadote, Mucomyst, and generic NAC were obtained.Results:
IV NAC was administered to 50 (2.9%) patients in the PRE group and to 183 (9.6%) patients in the POST group. Demographic data were similar for both groups. Adverse reactions to IV NAC included 2 allergic-type reactions and 1 complaint of chest tightness in the POST group and 1 allergic-type reaction in the PRE group.Discussion:
The release of Acetadote was associated with a 266% (2.9% to 9.6%) increase in IV NAC use. This change occurred despite a higher risk of serious adverse events with the IV route, an increase in cost when using Acetadote with equivalent treatment durations, and a lack of convincing data demonstrating that the IV route is superior in efficacy to the oral route.Conclusion:
The change in IV NAC usage without published rationale may be the result of effective promotional campaigns by the manufacturer of Acetadote or the assumption that newly approved products are superior to existing products.