Smoking-cessation drugs Champix (known as Chantix in the US) and Zyban are to carry the Food and Drug Administration’s strongest safety warning after concerns were raised over possible side effects.
The “Black Box” warning is based on research which suggests people taking the drugs experienced unusual changes in behaviour, leading to depression and suicidal thoughts.
GlaxoSmithKline’s Zyban contains the same active ingredient as the antidepressant Wellbutrin, which also carries the high-risk warning.
In response to the reports the FDA is calling for more research to be done into Champix, which is made by Pfizer, and Zyban to determine the extent of the side effects.
Pfizer officials said is it still in talks with the FDA over the content of the study, but said it could include patients with and without psychiatric conditions to determine the true incidence rate.
Labels on the Champix were updated in 2007 after reports of 37 suicides and more than 400 cases of suicidal behaviour in connection with the drug.
In February 2008, the FDA said the connection between Champix and serious psychiatric problems was increasing.
Copyright Press Association 2009