A study from Denmark shows that taking Viagra with some commonly prescribed drugs can cause serious side effects. People who take nitroglycerin for heart pain can go into shock if they take it with Viagra. Those who take beta blockers such as Tenormin. Coreg, Lopressor, Corgard, or Inderal will not be helped by phentolamine, another drug used to treat impotence. People on heparin can suffer uncontrollable bleeding on alprostadil, another drug used to treat impotence.

Many drugs are broken down by the same enzyme in the liver that breaks down Viagra and therefore could cause higher or lower blood levels of drugs such as the antifungal drug, ketoconazole, and the antiparkinson drug, entacapone. Another recent study shows that the vast majority of men who are impotent have normal blood levels of the male hormone, testosterone. That means that the most common causes of impotence are arteriosclerosis and diabetes.

1) Interactions between drugs for erectile dysfunction and drugs for cardiovascular disease. International Journal of Impotence Research, 2002, Vol 14, Iss 3, pp 178-188. U Simonsen. Aarhus Univ, Dept Pharmacol, Univ Pk 240, DK-8000 Aarhus C, DENMARK.

2) Is there any relation between serum levels of total testosterone and the severity of erectile dysfunction? International Journal of Impotence Research, 2002, Vol 14, Iss 3, pp 167-171. EL Rhoden, C Teloken, R Mafessoni, CAV Souto. Rhoden EL, Rua Jaragua 370 Apto 302, BR-90450140 Porto Alegre, RS, BRAZIL

Reported 9/2/02; checked 8/9/05

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