Which medication for addiction treatment is contraindicated in clients with a seizure disorder?

Bupropion is contraindicated in clients with a seizure disorder primarily because it lowers the seizure threshold. This means that it can increase the likelihood of seizures occurring in individuals who are already susceptible due to an underlying seizure disorder. This medication is often used for treating depression and for smoking cessation, but its capacity to provoke seizures makes it a risky choice for those with a history of seizures.

In contrast, the other medications listed do not carry the same contraindication. Varenicline is primarily used for smoking cessation and works by stimulating nicotine receptors in the brain. Naltrexone is utilized in the treatment of alcohol use disorder and opioid addiction, functioning as an opioid receptor antagonist without significant risks related to seizure activity. Disulfiram is used to promote abstention from alcohol by causing unpleasant reactions when alcohol is consumed but is not contraindicated for those with seizure disorders. Hence, Bupropion stands out as the medication that directly contraindicates use in patients with a seizure disorder.