22 May 2008

National Prescribing Service Limited (NPS) wants health professionals to be aware that following the release of a study in the USA recently the spotlight is back on varenicline (Champix). Reports of serious accidents, heart and vision problems, are fueling debate around the safety of the medicine.

NPS urges health professionals to monitor patients using varenicline for any behaviour and/or mood changes or any unusual symptoms or events that occur while taking the medicine.

“Psychiatric symptoms were previously noted so that information is not new,” said Ms Karen Kaye, Acting CEO, NPS. “But it’s important to take all reports of adverse events seriously, and this new report may be highlighting side effects that have not been previously identified.”

“When we have had a chance to properly review the data, if new information is revealed, we will be sure to share any findings with health professionals. In the meantime, patients should be encouraged to report side effects, particularly those relating to mood changes or psychiatric symptoms, and health professionals are encouraged to report adverse events to the Australian Drug Reactions Advisory Committee in the usual way,” she said.

Varenicline must be prescribed as part of a comprehensive program which includes smoking-cessation support and counselling to maximise its effectiveness.

An NPS RADAR review released in January noted that as with all new drugs, the full safety and efficacy profile is not known. Varenicline is a new drug in a new class of drugs, therefore some extra uncertainty exists about its safety profile.

Nausea was the most common adverse effect of varenicline in clinical trials. Other common adverse effects included insomnia, abnormal dreams, headache and constipation.

There are some post-marketing reports of new-onset depressed mood, suicidal thoughts or aggressive and erratic behaviour within days to weeks of starting varenicline in patients with and without pre-existing psychiatric illness. It is unclear whether these are caused by smoking cessation or by varenicline.

The safety and efficacy of varenicline in smokers with serious medical or psychiatric illness has not been established. Varenicline has a different mechanism of action to other smoking cessation therapies and is thoughtto work by reducing craving and withdrawal symptoms.

In clinical trials of generally healthy, motivated smokers, more people using varenicline (23%) had quit smoking at 1 year compared with those using bupropion or placebo (15% and 10%, respectively).

However the effectiveness of varenicline on long-term abstinence rates beyond 12 months has not been studied. The PBS will only subsidise one 12-week course of treatment of varenicline per patient per year. Varenicline was available on the PBS from 1 January 2008.

For consumers, varenicline was also reviewed in Medicine Update in January.

Health professionals can contact TAIS (Therapeutic Advice and Information Service) on 1300 138 677 if you have any questions.

ENDS

National Prescribing Service Limited (NPS) is an independent, non-profit organisation for Quality Use of Medicines. We provide accurate, balanced, evidence-based information and services to help people choose if, when and how to use medicines to improve their health and wellbeing. We are member-based and work in partnership with health professionals, government, pharmaceutical industry and consumers. NPS is funded by the Australian Government Department of Health and Ageing.