A tablet taken once a day to prevent inflammation of the lungs may become a regular part of the treatment of asthma patients.
The drug, montelukast, is the first of a new kind of anti-asthma medicine. It is intended as an add-on treatment, to be taken with existing drugs, to reduce day and night-time attacks.
Trials of the drug, to be sold under the brand name Singulair, have shown it cuts attacks in people with moderate asthma by half when taken with inhaled steroids. It is intended for use by adults and children over six years old with chronic mild to moderate asthma whose disease is inadequately controlled.
Professor Mike Silverman, chairman of the National Asthma Campaign's education committee, said: "For some, but by no means all people with asthma, it will offer a completely new way of controlling asthma symptoms. Our main message is that tablet treatments are not going to be suitable for everybody. It is a long way off before people with the condition will be able to take a once-a-day pill instead of an inhaler."
Professor Silverman said it was too early to say which patients would benefit most. "For those whose asthma is very mild, the tablet might replace existing preventer medication, but more studies are needed before this can be recommended."
"People with asthma have always relied on inhaler devices to deliver medication to their lungs. It is essential to talk with your doctor to find out if it is going to be appropriate for you."
The new drug is targeted at leukotrienes, chemicals in the lungs that produce asthmatic symptoms by causing the muscles in the airways to tighten, the cells to produce extra mucous and the lining to become inflamed. By blocking the action of the leukotrienes, inflammation is reduced and the tubes in the lung opened up, allowing the patient to breathe more easily.
In addition to helping people with chronic asthma, the new drug will be used to help stop asthma attacks brought on by exercise.
The suffering, illness and premature death caused by air-pollution from road traffic is costing at pounds 11bn a year, according to the British Lung Foundation.
The report says one-third of the population is susceptible to the effects of pollution, including young children, pregnant women and the chronically ill. It uses a "willingness to pay" method for assessing the impact of pollution on people's lives rather than assessing only the costs of treating pollution-related health problems.
The figure of pounds 11bn is obtained by multiplying the number of pollution- related illness events (days of cough, asthma attacks, etc) and premature deaths by people's willingness to pay to avoid the risk of them happening.
Epidemic of the modern world
Three-and-a-half million people in the UK are estimated to suffer from asthma, including 1.5 million children aged 2 to 15.
In 1995, around 1,621 people in the UK died as a result of the disease - one person every five hours. Before the Sixties there werearound 100,000 cases a year and just a handful of asthma-related deaths.
Asthma is the only treatable chronic condition in the Western world which is on the increase. The number of children with the disease has doubled since the Seventies, with on average 155 admitted to hospital every day.
There were more than 100,000 hospital admissions due to asthma attacks in 1993 - a 7 per cent rise on the previous year.
Annual prescriptions for asthma treatments almost doubled in the years 1982 to 1992 with the cost of NHS treatment rocketing from pounds 50m to pounds 350m during that time.
Asthma is caused by chemicals in the body which cause airways to tighten when asthmatics come in contact with certain allergens.