A new type of treatment to help smokers quit is now available in the UK.
Around 70% of smokers are reported to want to quit
Varenicline (champix) is the first non-nicotine drug developed specifically to help smokers give up.
The drug mimics the effect of nicotine on the body and is thought to work by both reducing the urge to smoke and relieving withdrawal symptoms.
Experts said there was likely to be heavy demand for the drug ahead of the ban on smoking in public places in England, which takes effect next July.
The drug is due to be assessed by the National Institute for Clinical Excellence (NICE) next year - in the run up to the ban.
The charity Action and Smoking on Health (ASH) has produced interim guidelines following discussions with the Department of Health to help health professionals prescribe the new treatment, which costs about £1.95 per day.
They report that the evidence from two randomised controlled trials show varenicline is superior to placebo and another available treatment buproprion.
However, individuals should only be prescribed the treatment as part of the support they receive through NHS stop smoking services and because it is a new drug patients should be encouraged to report any adverse effects, the advice states.
The main side-effect of the drug, which is generally taken for three months, seems to be nausea.
Varenicline, produced by Pfizer, is unusual as it both stimulates and blocks specific nicotinic receptors in the brain.
It is thought that by stimulating the receptor it mimics the effects of nicotine to reduce cravings but, at the same time, partially blocks the receptor preventing nicotine from binding to it, resulting in a weaker response in people who give in to temptation and have a cigarette.
Around 44 per cent of smokers who took part in the trials were able to quit using the drug at 12 weeks.
Dr Jotham Coe, a researcher and ex-smoker who helped to develop the drug, said the drug acted as a "shield" to the effects of nicotine addiction.
"It's been very well-received in the US, only 2.6% dropped out of the trials because of side-effects."
NHS quit services
Currently people who want to quit smoking can use nicotine replacement products or buproprion - an antidepressant which was found to help people stop smoking.
Deborah Arnott, director of ASH, said: "Varenicline appears to be a useful additional aid to stopping smoking. We anticipate that there will be significant demand for this new drug, given that more than 70% of smokers say that they would like to stop smoking. We trust that the new guidance will help practitioners prescribe the drug to those patients who are most likely to benefit from it."
Dr Alex Bobak, a GP in Wandsworth, south London and smoking cessation expert, has already used the drug as part of a clinical trial and said it had proved popular among patients.
"There's going to be a lot of interest in this medication leading up to the smoking ban. GPs and stop smoking services need to be prepared.
"The most important thing is that the right patients are getting it. This is suitable for any smoker who is motivated. It's well tolerated and safe but it's important that those who use it are the ones who are going to benefit."
He added that anyone who wanted to stop smoking could contact their local stop smoking service directly without going through their GP.
Lion Shahab from Cancer Research UK's health behaviour unit, said: "Varenicline is a promising new drug specifically designed to help smokers quit and it is a welcome addition to the existing range of treatments available.
"Judgments about its use are best made by the prescribing doctor in consultation with the smoker."