Estimated risk of hepatotoxicity after an acute acetaminophen overdose in alcoholics.
A published logistic regression model based on the Canadian Acetaminophen Overdose Study registry was used to calculate the risk of hepatotoxicity after an acute acetaminophen overdose and to estimate a treatment threshold line for alcoholic patients who did not co-ingest alcohol (i.e., abstinent alcoholics) on the Rumack-Matthew nomogram. The risk of hepatotoxicity in nonalcoholic and abstinent alcoholic patients was calculated at the acetaminophen concentration of 150 microg/ml at 4h (37.5 microg/ml at 12h) treatment threshold line. This corresponds to the "possible risk" line on the Rumack-Matthew nomogram and represents a 1.6% risk of hepatotoxicity for nonalcoholic patients at or below this line. At or below this same 150 microg/ml at 4-h line, abstinent alcoholic patients have a hepatotoxicity risk of 10.7%. The risk of hepatotoxicity in abstinent alcoholics' equivalent to that of nonalcoholics (i.e., 1.6%) occurs at a lower acetaminophen concentrations treatment threshold line, that is, 104 microg/ml at 4h (26 microg/ml at 12h). Because of difficulties plotting this new line on the familiar Rumack-Matthew semilogarithmic scale, a line connecting 100 microg/ml at 4h (25 microg/ml at 12h) is proposed. This line equates to a 1.1% risk of hepatotoxicity in abstinent alcoholic patients. The analysis supports the observation that based on the published model abstinent alcoholics might have a greater risk of hepatotoxicity after an acute acetaminophen overdose. This proposed new risk line can be used in hypothesis generation for future clinical studies in this alcohol related problem.
Ali
Fahad M
FM
Division of Medical Toxicology, Department of Emergency Medicine, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA. fahadalimd@hotmail.com
Boyer
Edward W
EW
Bird
Steven B
SB
D000082:Acetaminophen / Q000506:poisoning*; D000111:Acetylcysteine / Q000627:therapeutic use; D000437:Alcoholism / Q000150:complications* / Q000453:epidemiology*; D018712:Analgesics, Non-Narcotic / Q000506:poisoning*; D002170:Canada / Q000453:epidemiology; D056486:Chemical and Drug Induced Liver Injury / Q000453:epidemiology* / Q000473:pathology*; D062787:Drug Overdose / Q000453:epidemiology* / Q000473:pathology*; D016166:Free Radical Scavengers / Q000627:therapeutic use; D006801:Humans; D008099:Liver / Q000473:pathology*; D015233:Models, Statistical; D012042:Registries; D012306:Risk
D018712:Analgesics, Non-Narcotic; D016166:Free Radical Scavengers; D000082:Acetaminophen; D000111:Acetylcysteine