Introduction: We sought to determine whether or not the causes and consequences of drug-induced seizures have changed in the last decade.Methods: We conducted a retrospective review of all calls to the California Poison Control System in 2003 in which seizures occurred in association with poisoning or drug intoxication. We reviewed the poison center chart of each case to determine the drug(s) involved, the type of seizures, and the medical outcome. We compared the cause of reported seizures to that found in previous investigations.Results: 386 cases were evaluated and related to poisoning or drug intoxication. The leading causes of seizures were bupropion (89 cases, 23%), diphenhydramine (32 cases, 8.3%), tricyclic antidepressants (30 cases, 7.7%), tramadol (29 cases, 7.5%), amphetamines (27 cases, 6.9%), isoniazid (23 cases, 5.9%), and venlafaxine (23 cases, 5.9%). Since 1993, there was a statistically significant increase in antidepressant related seizures but a decrease in TCA and cocaine related seizures. In 265 patients (68.6%) only a single seizure was reported, while 3.6% (14 cases) reported status epilepticus. Two-thirds (65.5%) of the cases involved suicide attempts and 14.8% the direct result of drug abuse. There were 7 deaths. Of the 7 deaths, 4 people had significant hyperthermia. There was a statistically significant increased risk of death associated with stimulant exposure.Conclusion: While tricyclic antidepressants, antihistamines, stimulants, and isoniazid remain common causes of drug induced seizures, bupropion, tramadol, and venlafaxine have emerged as common causes of drug-induced seizures for which poison center consultation is requested.

A retrospective review of cases consulted by the San Francisco Bay Area Regional Poison Control Center during a 2-year period was performed to determine the causes and consequences of seizures associated with poisoning and drug intoxication. Of 233 charts coded as involving seizures, 191 occurred in humans and were available for analysis. The leading causes of seizures reported to the Poison Control Center were cyclic antidepressants (55 cases, 29%); cocaine and other stimulants (55 cases, 29%); diphenhydramine and other antihistamines (14 cases, 7%); theophylline (10 cases, 5%); and isoniazid (10 cases, 5%). Stimulants and diphenhydramine were more likely than other drugs to produce brief, self-limited seizures. In contrast, poisoning by cyclic antidepressants, cardiodepressant antiarrhythmic agents, or theophylline was more likely to be associated with death. Seizures in elderly patients were more likely to result in complications and death. The frequency of seizure-related cases by substance type was also compared with the results of an earlier survey performed in 1981, and found a striking increase in the proportion of seizures caused by cocaine and (23% in 1988 to 1989 compared with 4% in 1981). Poison Control Center data can provide valuable information about the causes and consequences of drug-related medical complications, as well as highlight changing trends in drug-related injury.

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