Drug regulators are set to bolster the warning requirements of two popular smoking cessation drugs in response to continuing concerns over their serious psychiatric side effects.
The Therapeutic Goods Administration (TGA) said it would "strengthen" prescribing and consumer information warnings for Champix (varenicline) and Zyban (bupropion), following a decision earlier in the week by its US counterpart.
The US Food and Drug Administration (FDA) will compel manufacturers to include a boxed warning about their drugs' impact on mental health, including a risk of depression, aggression and suicidal behaviour.
"The risk of serious adverse events while taking these products must be weighed against the significant health benefits of quitting smoking," director of FDA's Center for Drug Evaluation and Research, Dr Janet Woodcock, said.
The FDA had reviewed reports of adverse psychiatric effects in patients and the announcement is the latest move in a series of warnings from the regulator about the drugs.
With a combined cost to the Pharmaceutical Benefits Scheme of $57.1 million in the 12 months to May this year, the two drugs have also been the subjects of reports in Australia.
Champix-related side effects were last highlighted in the December edition of the Australian Adverse Drug Reactions Bulletin, with almost three quarters of complaints about the drug describing psychiatric symptoms.
"To the end of March, 2009, the TGA had received 544 and 1,983 reports of patients suspected of experiencing adverse events possibly related to Champix and Zyban treatments respectively," a statement from the TGA said.
A spokesperson for Zyban manufacturer GSK said information on the "potential benefits and risks associated with Zyban, including mental health considerations" were already included in the drug's product and consumer information.
A spokesperson for Champix maker Pfizer said the company would work closely with the TGA to make sure the drug's information was "up to date".