Marijuana and heroin have a low relative risk of epileptogenesis, and some data suggest that marijuana has an anticonvulsant effect.106 However, heroin in particular may be mixed with contaminants that lower seizure threshold when injected. Opiate withdrawal produces myoclonus and shivering that can be mistaken for seizure activity.107 In a case-control study by Ng et al.,106 some heroin-abusing patients who were admitted with new-onset seizures were found to have other serious conditions, including sepsis, brain abscess, and acquired immunodeficiency syndrome (AIDS).

Tramadol, a synthetic narcotic used to treat pain, was associated with a high incidence of seizures shortly after it was introduced.108 As more experience with the drug was gained, however, the usual dose was lowered and its use was avoided in patients taking antidepressants, neuroleptics, or other opioids. Subsequent to these changes, the incidence of seizures has fallen to less than 1%.109

Ng and Alvear110 reported generalized seizures in more than half of those who used dextropropoxyphene (Darvon), a morphine analog. Seizures have also occurred in people who abuse propoxyphene, meperidine (Demerol), and “Ts and blues” (Talwin [pentazocine] and tripelennamine).104

Former heroin addicts using methadone dislike AEDs (such as phenytoin and carbamazepine) that induce hepatic metabolizing enzymes, claiming that the AEDs “eat” their methadone. Valproic acid, levetiracetam, gabapentin, and lamotrigine are generally more acceptable to these patients if they require AEDs.107

Adapted from: Koppel BS. Contribution of drugs and drug interactions (prescribed, over the counter, and illicit) to seizures and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;155–173.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised March 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.