New warnings about the risks in using the anti-impotence drug, Viagra, are being issued in the United States. The Food and Drug Administration (FDA) says it agreed with the manufacturer, Pfizer, on extra wording on the drug's label, after reports of deaths and severe side-effects among Viagra users. While stressing that it still believes Viagra is safe, the FDA says the new warnings make clear that patients with a history of particular health problems should be carefully examined by a doctor before they are prescribed the drug. Since Viagra went on the market in April, 69 men have been reported to have died after taking it. "The revised labelling addresses post-marketing reports of heart attacks, sudden cardiac deaths and hypertension," the FDA said in a statement. [ image: History of heart problems or low blood pressure is seen as a risk factor] History of heart problems or low blood pressure is seen as a risk factor It said that many groups had been left out from the original safety trials for Viagra, including men who had suffered heart attacks, stroke or dangerous arrhythmia within six months, men with dangerously high or low blood pressure, men with heart failure or unstable angina (chest pains), or retinitis pigmentosa, an eye disorder. "The new labelling notes that if Viagra is prescribed for these patients, it should be done with caution," the FDA said.