Cimetidine and Viagra

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Cimetidine may increase the blood levels and effects of sildenafil. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience nausea, shortness of breath, dizziness, lightheadedness, fainting, visual disturbances, ringing in the ears, vision or hearing loss, chest pain or tightness, irregular heartbeat, and/or priapism (prolonged and painful erection unrelated to sexual activity), as these may be signs and symptoms of excessive sildenafil levels. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

MONITOR: Coadministration with cimetidine may increase the plasma concentrations of sildenafil. The mechanism is cimetidine inhibition of sildenafil metabolism via CYP450 isoenzymes in the intestinal wall and liver. In one study, 20 healthy male volunteers received a single 50 mg dose of sildenafil on days 1 and 5, and either cimetidine 800 mg or placebo on days 3, 4, 5, and 6. Coadministration of cimetidine caused a statistically significant increase in sildenafil peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of 54% and 56%, respectively, compared to placebo. Cimetidine also increased the AUC of sildenafil's major metabolite by 30%. Sildenafil was well tolerated either alone or in combination with cimetidine in the study, and no clinically significant changes in blood pressure and pulse rate or abnormalities in ECG were reported.

MANAGEMENT: Based on the magnitude of the reported interaction, no dosage adjustment for sildenafil should be necessary during coadministration with cimetidine. However, patients should be advised to promptly notify their physician if they experience potential signs and symptoms of sildenafil toxicity such as pain or tightness in the chest or jaw, irregular heartbeat, nausea, shortness of breath, visual disturbances, syncope, or prolonged erection (greater than 4 hours).

Cimetidine

Generic Name: cimetidine

Brand name: Tagamet HB, Tagamet

Synonyms: n.a.

What is Cimetidine?

Viagra

Generic Name: sildenafil

Brand name: Revatio, Viagra

Synonyms: n.a.

What is Viagra?