Warning on ED drug-drug interactions

People who take three well-known erectile dysfunction medications should be extremely careful if they take any of 56 other drugs, including many  commonly prescribed anti-angina and certain blood pressure medications,  grapefruit juice and St John's Wort, US consumer group Public Citizen  warns on its WorstPills.org web site.

The three ED drugs are Viagra (sildenafil), Cialis (tadalafil) and  Levitra (vardenafil). The 56 drugs fall into three categories: those  that can cause a life-threatening drop in blood pressure when taken with  ED agents; ones that prevent the body from eliminating ED drugs, thereby  leading to an overdose; and those that speed up the metabolism of the  ED products, thereby reducing their effectiveness. Grapefruit juice  also is listed in the second category because it acts like a drug in  this circumstance.

"Those who take erectile dysfunction drugs are generally older men, who  are more likely to be taking other medications as well. It is critical  that they be aware of the potential for dangerous interactions," said  Sidney Wolfe, director of the Health Research Group at Public Citizen.