Probable Tapentadol-Associated Serotonin Syndrome After Overdose.

PURPOSE: Drug-induced serotonin syndrome is a potentially life-threatening condition. An Ovid MEDLINE, and PubMed search from 1950 to October 2015 revealed one published case report of suspected tapentadol-induced serotonin syndrome. We report a probable case of tapentadol-induced serotonin syndrome after overdose. CASE SUMMARY: A 48-year-old male was found unresponsive after a witnessed overdose of medications including tapentadol. After administration of naloxone by emergency medical services, the patient became combative and presented with altered mental status. He was managed with physical and pharmacologic restraints in the emergency department. Other medications that could be implicated in the patient's presentation include duloxetine and amitriptyline. It was suspected that the opioid properties of tapentadol were masking the patient's signs and symptoms of serotonin syndrome. The patient was admitted to the medical intensive care unit, remained stable, and was discharged 2 days later. Currently, there is one published case report of suspected tapentadol-induced serotonin syndrome after an overdose. The manufacturer of tapentadol reported no cases of serotonin syndrome during clinical trials, but there have been postmarketing cases reported with co-administration of other serotonergic drugs. CONCLUSION: We report a probable case of tapentadol-induced serotonin syndrome after overdose. Further research is needed to better understand the pharmacology and incidence behind this adverse event.

Irreversible atorvastatin-associated hearing loss.

Drug-associated ototoxicity is a potentially irreversible adverse event. Among the several 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) available in the United States, only atorvastatin is associated with tinnitus, but none are associated with any forms of hearing loss. A search of the published literature (1950-August 2011) revealed no published case reports of ototoxicity associated with statins. To our knowledge, we describe the first case of progressive, irreversible hearing loss in a 32-year-old man 18 months after starting atorvastatin therapy. He began taking atorvastatin 20 mg every evening for treatment of hypercholesterolemia. Six months later, he complained of occasional episodes of tinnitus, which resolved spontaneously. An audiogram was obtained and was normal. By 18 months, the tinnitus became continuous. Another audiogram revealed bilateral "cookie-bite" middle-frequency hearing loss. Atorvastatin was immediately discontinued, and the patient was fitted with hearing aids. Four years after drug discontinuation, his hearing loss had neither progressed nor regressed. Use of the Naranjo adverse drug reaction probability scale indicated a possible (score of 2) temporal and causal relationship between the patient's hearing loss and atorvastatin. Causes of "cookie-bite" hearing loss include chronic exposure to loud noises, presbycusis, genetic predisposition, and drugs. The manufacturer of atorvastatin has received three unpublished cases of deafness, but claims that causal relationships were not established. Despite these claims by the manufacturer, based on this case report, we recommend that clinicians and patients be aware of the risk of atorvastatin-associated tinnitus and permanent hearing loss. Further research is needed to better understand the mechanism and frequency of this adverse event.