Los Angeles: A pill to help smokers fight cigarette addiction has been approval by the FDA in the US and could also gon on sale in Britain.

Chantix (barenicline tartrate), made by pharmaceutical company Pfizer, works by duplicating the affect of nicotine.

A recent study published in the Archives of Internal Medicine found almost half the smokers who took Chantix managed to quit. The trials suggest it is twice as effective as another drug Zyban, which is an anti-depressant.The new drug works by blocking withdrawal symptoms.

In the US study, researchers from Los Angeles Clinical Trials and the Varenicline Study Group tested the drug, Zyban or a placebo on 626 men and women aged 18 to 65 to either Chantix in three different doses, Zyban or a placebo.

After 12 weeks, 38.8 per cent of those who took Chantix managed to quit, compared to 19.8 per cent for Zyban and 10.6 per cent for the placebo.

Nicotine cravings were significantly reduced for those taking the highest dose of Chantix compared to the placebo. Zyban also reduced craving, but to a lesser extent.

The pill had some side effects, including nausea, but spacing out the doses over the course of the day appeared to lessen the impact.