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Collections under which this article appears    - Collections dans lesquelles cet article paraît: Adverse drug reactions Regulation

Adverse events with Zyban (buproprion)

Michael Kolber^*, G. Richard Spooner and Olga Szafran

*Assistant Clinical Professor, Department of Family Medicine, University of Alberta, Edmonton, Alta.; Professor and Chair, Department of Family Medicine, University of Alberta, Edmonton, Alta.; Research Coordinator, Department of Family Medicine, University of Alberta, Edmonton, Alta.

Barbara Mintzes and associates¹ expressed concern last year over differences between countries in physicians' reporting of adverse reactions to prescription drugs. To illustrate, they cited significant differences in the reported rates of adverse reactions and deaths attributed to Zyban (buproprion) in Canada and the United Kingdom. We have data suggesting that the actual rates of adverse reactions related to the use of Zyban for smoking cessation in community clinical practice may exceed rates reported elsewhere.

Zyban has been commercially available for smoking cessation since 1998. Most of the evidence pertaining to efficacy and rates of adverse reactions stems from 2 large trials,^2,3 both funded by GlaxoSmithKline, the maker of Zyban. These studies showed a relatively low rate of adverse reactions and claimed that only 6% to 8%² and 11.9%³ of patients discontinued the drug because of the adverse reactions. However, about 35% of patients overall did not complete the trials.

To determine if rates of adverse reactions were higher in clinical practice than in the literature, we undertook an independent study to examine adverse events associated with Zyban for smoking cessation in rural family practice. The study was carried out in Peace River, Alta. (population 6500) during the period April 2001 to February 2002. Patients 18 years of age or older who received a first-time prescription of Zyban for smoking cessation were enrolled and followed prospectively for 2 months. Previous Zyban users, those who were using Wellbutrin (another brand of bupropion) and those with an underlying seizure disorder were excluded from the study.

We enrolled a total of 39 patients, of whom 15 (38%) discontinued Zyban because of adverse reactions. The most common reasons for discontinuation were neuropsychiatric symptoms (tremors, agitation or confusion), insomnia and rash. An additional 7 patients (18%) decreased the dosage from twice daily to once daily because of adverse reactions. In total, 32 (82%) of the patients reported at least one adverse reaction (including neuropsychiatric symptoms reported by 16, insomnia by 12, dry mouth by 9 and rash by 7). Nine patients (23%) required additional medical care (a total of 10 visits), and one patient (3%) was admitted to hospital. Eleven (28%) of the patients quit smoking, and we are currently determining if those who quit continue to be nonsmokers.

Because of the small sample size, the generalizability of our findings is unknown. However, they indicate that rates of discontinuation because of adverse effects may exceed those previously reported.^2,3 Therefore, larger, independent, community-based studies are needed. It has been postulated that less than 10% of all adverse events are reported.¹ To improve this rate, physicians need to be more diligent in reporting adverse reactions to the Canadian Adverse Drug Reaction Moni- toring Programme. Only then can we obtain a true estimate of adverse reaction rates for medications commonly prescribed in Canada.

Michael Kolber Assistant Clinical Professor G. Richard Spooner Professor and Chair Olga Szafran Research Coordinator Department of Family Medicine University of Alberta Edmonton, Alta.

Footnotes

Competing interests: None declared.

Acknowledgement: This study was funded by the Alberta Rural Physician Action Plan.

References

1. Mintzes B, Bassett K, Wright JM. Drug safety without borders: concerns about buproprion [letter]. CMAJ 2002;167(5):447.[Free Full Text]
2. Hurt RD, Sachs DP, Glover ED, Offord KP, Johnston JA, Dale JC, et al. A comparison of sustained-release buproprion and placebo for smoking cessation. N Engl J Med 1997;337(17): 1195-202.[Abstract/Free Full Text]
3. Jorenby DE, Leischow SJ, Nides MA, Rennard SI, Johnston JA, Hughes AR, et al. A controlled trial of sustained-release buproprion, a nicotine patch, or both for smoking cessation. N Engl J Med1999;340(9):685-91.[Abstract/Free Full Text]

Reprint (PDF) Version of this Article    - Tiré à part (PDF) de cet article Email this article to a friend eLetters: Submit a response to this article    - Lettres électroniques : répondre à cet article Similar articles found in - Articles semblables dans: eCMAJ PubMed PubMed Citation - Citation PubMed Search Medline for articles by    - Chercher dans Medline des articles de: Kolber, M. || Szafran, O. Alert me when - Veuillez m'avertir si: new articles cite this article - de nouveaux articles citent cet article Download to Citation Manager    - Télécharger à un logiciel de gestion des citations

Collections under which this article appears    - Collections dans lesquelles cet article paraît: Adverse drug reactions Regulation