BRIEF REPORT Misuse of acetaminophen in the management of dental pain Céline Clement 1,2 * , Julien Scala‐Bertola 3 , Lucie Javot 4 , Marie José Royer‐Morrot 3 , Pierre Gillet 3,4 , Philippe Trechot 4 , Nadine Petitpain 4 and Nicolas Gambier 3 1 Emergency Dental Service, CHU of Nancy, Nancy, France 2 Faculty of Dentistry, Université Henri Poincaré, Nancy, France 3 Department of Clinical Pharmacology and Toxicology, CHU of Nancy, Nancy, France 4 Regional Pharmacovigilance Center of Lorraine, CHU of Nancy, Nancy, France ABSTRACT Purpose We highlight the risk associated with acetaminophen misuse in patients having dental pain in France based on a series of cases of unintentional acetaminophen overdose reported by the Emergency Dental Service of Nancy over a 9‐month period. Methods Data were collected by querying the French Pharmacovigilance database. Each retrieved clinical data were reviewed by a clinician. Results Thirteen cases of acetaminophen overdose were reported to the Regional Pharmacovigilance Center of Lorraine, Nancy, France. Most cases (10/13) concerned men aged 20–40 years old. Mild, unspecific clinical symptoms were observed in seven of 13 patients. The median value of the supposed ingested dose was 137 mg/kg/24 h. Liver enzyme activity was tested in 10 patients and was abnormal in four patients. N‐acetylcysteine treatment was administered to four patients. Conclusions We propose that even patients with mild clinical symptoms with a supposed ingested dose of acetaminophen greater than 150 mg/kg/24 h should be referred to an emergency department and that liver enzyme activity should be analyzed. No case of liver failure was observed during our short survey. However, hepatotoxicity of repeated supratherapeutic ingestion of acetaminophen was suspected in four patients. Patients and practitioners should thus be better informed about the risk of unintentional acetaminophen overdose following supratherapeutic acetaminophen ingestion. Copyright © 2011 John Wiley & Sons, Ltd. key words—acetaminophen; misuse; unintentional overdose; dentistry; dental pain Received 25 July 2010; Revised 5 April 2011; Accepted 14 April 2011 INTRODUCTION Dental pain is a frequent cause of emergency dentistry consultation. However, patients have often already taken analgesics such as acetaminophen or ibuprofen before consulting. These analgesics are widely prescribed and can also easily be obtained without prescription. Hepa- totoxicity of acetaminophen following acute intoxica- tion in patients with suicidal intent is well‐known among practitioners. Toxicity of repeated supratherapeutic ingestion is less well documented but is a matter of concern. 1,2 Acetaminophen is safe in quantities up to a maximum of 4 g per day. 3 However, when patients have refractory dental pain, repeated ingestion of suprather- apeutic doses may occur, leading to unintentional overdose and possibly to hepatotoxicity. 4 The risk of unintentional acetaminophen overdose in patients having dental disease appears to be a public health problem that has been raised in the United Kingdom. 5,6 Our aim was to investigate the frequency and the characteristics of unintentional acetaminophen overdose in patients consulting for dental pain in the Emergency Dental Service of our hospital. Here, we present the results of a retrospective review of unintentional acetaminophen overdoses reported by the Emergency Dental Service of our hospital to the Regional Center of Pharmacovigilance of Lorraine over a 9‐month period. METHODS In France, adverse drug reactions, including misuse, are spontaneously reported by health professionals to Regional Pharmacovigilance Centers (RPC) before transmission to the French national health authority. *Correspondence to: C. Clement, Université Henri Poincaré, Nancy I, Faculté d’Odontologie, Avenue du Maréchal De Lattre De Tassigny, 54000 Nancy, France. E‐mail: cclement8@hotmail.fr Copyright © 2011 John Wiley & Sons, Ltd. pharmacoepidemiology and drug safety 2011; 20: 996–1000 Published online 1 July 2011 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/pds.2171