Sustained-release bupropion (bupropion SR) was first launched in the US in 1997 as an aid to smoking cessation and has since been launched in many other countries. Adverse events associated with the use of bupropion SR at the recommended dosage of 150mg twice daily in clinical trials most commonly included insomnia, headache, dry mouth, nausea and anxiety; insomnia and anxiety are also recognised as symptoms of nicotine withdrawal. Only insomnia and dry mouth occurred significantly more frequently with bupropion SR than with placebo. Relative to placebo, no significant changes in mean values for heart rate, blood pressure or routine laboratory parameters have been reported in smokers using bupropion SR alone in clinical trials. When bupropion SR was compared with a nicotine transdermal patch in a clinical trial, insomnia predominated in the bupropion SR group, while dream abnormalities were more common in smokers using the nicotine patch. Bupropion SR and the nicotine transdermal patch in combination can be used safely (with appropriate monitoring) as an aid to smoking cessation. Infrequent but clinically important adverse reactions to bupropion SR include seizures and hypersensitivity reactions: in controlled clinical trials of bupropion SR (300 mg/day), where smokers were carefully screened for risk factors for seizure, the incidence of both seizures and severe hypersensitivity reactions was approximate to0.1% for each event. In order to avoid a risk of seizure of greater than 0.1%, smokers should be screened for predisposing risk factors and adhere to the manufacturer's dosage recommendations (maximum daily dose of 300mg). Thus, bupropion SR is generally well tolerated, as seen by the low discontinuation rate due to an adverse event in clinical trials (6 to 12%). The most common adverse events (insomnia and dry mouth) are generally transient and often resolve quickly without therapeutic intervention; they can be managed if necessary by a reduction in bupropion dose.
