What You Should Not Take with Viagra

Jan 06, 2009
Men, using erectile dysfunction drugs such as Viagra, should be aware of the other medications and supplements they take as their interactions with ED drugs may potentially dangerous. Such medications as blood pressure drugs, certain antibiotics, herbal supplement St. John's wort and even grapefruit juice were found to interact badly with common ED drugs, the US consumer group Public Citizen reports.

As much as 56 substances were included in the list of substances that do not mix well with erectile dysfunction drugs Viagra, Cialis and Levitra. ED drugs are popular among older men who may also take other medicines to treat other health conditions. However, this may lead to unwanted consequences, lowering blood pressure, causing the overdose of ED drug or making ED drug ineffective.

Erectile dysfunction drugs work by dilating blood vessels, enhancing blood flow to the penis that results in erection. It is known that the enzyme CYP3A4 takes part in metabolism of Viagra and other ED drugs. Certain medications can interfere with the function of this enzyme.

Medicines, known as nitrates, which are often taken to treat cardiovascular diseases, work by widening blood vessels. When taken together with Viagra, Levitra or Cialis these drugs may lower blood pressure and this may lead to such consequences as heart attack or stroke.

Drugs, known as alpha blockers, used to treat high blood pressure, may excessively decrease blood pressure when taken with ED drugs. These include doxazosin (CARDURA), prazosin (MINIPRESS), terazosin (HYTRIN), tamsulosin (FLOMAX) and alfuzosin (UROXATRAL).

Some drugs which inhibit the enzyme responsible for metabolizing Viagra and other ED drugs may contribute to the increased toxicity. These include amprenavir (AGENERASE), ketoconazole (NIZORAL), itraconazole (SPORANOX) or ritonavir (NORVIR), fluconazole (DIFLUCAN) and others. Grapefruit juice may also increase ED drugs toxicity.
Other medicines may otherwise boost the activity of the CYP3A4 and thus reduce the effectiveness of ED drugs. These include such Dexamethasone (DECADRON, HEXADROL, MYMETHASONE), Rifampin (RIFADIN, RIMACTANE) as well as herbal supplement St. Johnís wort, which is often used in treatment of depression.

Taking into account the possible negative consequences of ED drugs interactions with other medicines it is recommended to inform your physician about it.