List of 56 Drugs That Should Not Be Mixed With Viagra Contains Some Surprises

(MoneyWatch)  Public Citizen has published a list of 56 drugs that interact badly with erectile dysfunction pills such as Pfizer's Viagra. Public Citizen's WorstPills.com site reports:

In combination with ED drugs, these 56 drugs can cause dangerous falls in blood pressure that could lead to a heart attack or stroke; a potentially harmful "overdose," even when taking the recommended amount; and decrease the effectiveness of the ED drugs themselves.

The drugs include the usual suspects, such as nitrates for blood pressure. Taken in combination with Viagra, Cialis ior Levitra nitrates can lead to potentially lethal drops in blood pressure.

But the list also includes some surprises -- household name drugs that shouldn't be taken with ED pills -- including Flomax, Provigil and grapefruit juice. Some drugs increase plasma concentrations of ED drugs, potentially leading to toxicity, and others reduce those concentrations, making the drugs ineffective. Some examples:

• Potential low blood pressure triggers:
• Flomax (Boehringer Ingelheim)

• Potential toxicity:
• Reyataz (Bristol-Myers Squibb)
• Grapefruit juice
• Diflucan (Pfizer)
• Gleevec (Novartis)
• Crixivan (Merck)
• Tykerb (GlaxoSmithKline)
• Mifeprex (Danco Labs)
• Viracept (Pfizer)
• Ketek (Sanofi-Aventis)

• Potential Inhibitors:
• Sustiva (BMS)
• Provigil (Cephalon)
• Viramune (Boehringer)