Viagra (Sildenafil Citrate)

How can Viagra interact with other medicines?

Viagra can interact with the following groups of drugs:

H2 Histamine receptor blockers - Cimetidine

In concomitant application Cimetidine significantly increases Viagra blood level and thus increases the risk of Viagra side effects. If Viagra is prescribed, ask your doctor for an alternative to cimetidine

CYP 3A4 Inhibitors

Viagra is metabolized in the liver under the action of CYP 3A4 enzymes. Some medications that inhibit these enzymes in the liver may increase Viagra blood levels leading to Viagra side effects. Talk to your doctor if you take any inhibitors of CYP 3A4

Alpha Blockers

Those patients taking Viagra and alpha blockers may experience lightheadedness, dizziness, or fainting. If you take any Alpha Blocker, the dose of Viagra should not exceed 25mg 4 hours after or before taking Alpha Blocker.

Blood pressure drugs

Hypotensive drugs when used with Viagra may cause extremely low blood pressure. Talk to your doctor about the dose adjustment of your blood pressure medication.

Nitrates

Viagra is strictly contraindicated for use by patients that take any Nitrates (nitrogen oxide donors) - Nitroglycerin and its analogues, because concomitant application may lead to severe drop of blood pressure.

Other Phosphodiesterase Type 5 Inhibitors (PDE5 Inhibitors)

Viagra is not recommended for use with other Ed drugs from PDE5 group of medicines. Other PDE5 medications

If you take any other medical preparations including RX and over-the-counter drugs, herbal supplements, make sure to let your doctor know.