A DRUG with the same active ingredient as Viagra is to be offered to patients suffering from a rare life-threatening condition.

People with pulmonary arterial hypertension (PAH) could be offered a new treatment, Revatio, with the same active ingredient, sildenafil citrate, as Viagra.

Sufferers from PAH have increased pressure in the blood vessel that leads from the heart to the lungs.

This leaves them with debilitating symptoms, such as breathlessness, fainting, chest pains and tiredness.

Clinical development by pharmaceutical firm Pfizer showed that giving sildenafil citrate reduces blood pressure in the artery and improves the ability of PAH patients to exercise.

There are about 4,000 people with a probable diagnosis of PAH in the UK, with 4,000 believed to be undiagnosed.

The Revatio tablet is white and round to distinguish it from the Viagra blue diamond- shaped tablet for erectile dysfunction.

Research has shown that Viagra can be used for medical problems in addition to impotence.

These problems include the inflammatory bowel disorder Crohn's disease. Viagra also reduces the harmful effect of stress on the heart.