Health authorities in the Philippines cautioned people against taking the anti-smoking drug varenicline as it may cause behavioural and psychiatric side effects.
The drug, manufactured by the pharmaceutical giant Pfizer under the brand name Chantix, was introduced in the Philippines in June 2007 under a "monitored release scheme," according to the health department's Bureau of Food and Drugs.
"Although there has not been any report of adverse reaction/event among local patients, (the government) has decided to issue this warning in the best interest of the patients and the public, in general," said the government agency's director, Leticia Barbara Gutierrez.
She did not say how many people were taking the medication in the Philippines, but that those who are should "stop taking the drug and contact their doctors" if they notice psychological changes, such as suicidal thoughts.
Gutierrez said the US Food and Drug Administration issued a public health advisory in May that warned of "severe changes in mood and behaviour in patients taking Chantix."
Joshua Ramos, deputy director of the bureau, said it would order the product's recall if the United States did the same.
World Health Organisation data show 34.7 percent of adults in the Philippines are smokers, along with 15.9 percent of youth aged between 13 and 15.