Short-term effectiveness of bupropion for assisting smoking cessation in general practice

To the Editor: As noted in the letter by Chapman and Jamrozik,1 there was substantial prescribing of bupropion sustained release (Zyban SR; GlaxoSmithKline) following its Pharmaceutical Benefits Scheme (PBS) listing from 1 February 2001. The drug has been the subject of extensive publicity following reports of adverse drug reactions and deaths of patients while taking bupropion. Although bupropion has been shown to be effective in two key clinical trials,2,3 there are no studies of effectiveness when prescribed in the context of Australian general practice.

We conducted a study of short-term effectiveness involving 11 general practice registrars working in eight practices in south-west and southern Sydney. Each registrar identified from practice prescribing records 10–15 patients prescribed bupropion after 1 February 2001. These patients were followed up via a telephone questionnaire 10 weeks after the date of prescription. The questionnaire elicited information on the use of bupropion, patient-reported abstinence rates, adverse effects and use of support services. Biochemical validation of smoking status was not conducted.

Interviews with 151 patients were conducted between April and August 2001 (see Box). Patients completing seven weeks or more of therapy were significantly more likely to report both continuous abstinence (P = 0.01) and point-prevalence abstinence (P = 0.002). Eighty-three patients reported adverse effects, the five most common being insomnia (14%), headaches (11%), nausea (8%), dry mouth (5%) and irritability (4%). No convulsions were reported. Patients who made use of one or more support services for cessation counselling were no more likely to report point-prevalence abstinence at follow-up than those who did not (P = 0.8).

Our study was not based on a random sample of GPs or patients, and we did not collect data on the total number of patients treated with bupropion in these practices over the study period. Bearing in mind these limitations, the study has a number of notable findings. Despite the wording of the PBS authority "for use within a comprehensive treatment program'', fewer than half the patients reported using any support service. There was also a low rate of completion of the recommended course of treatment (less than 20% of patients). While the short-term abstinence rates among the patients followed up were encouraging, and not dissimilar to rates found in clinical trials,2,3 there is clearly a need to look at strategies to encourage patients to adhere to the prescribed course of treatment and to make use of cessation support services. We suggest patients be invited back for at least two follow-up GP visits following prescribing of bupropion, as well as being made aware of other support services.