Viagra | sildenafil

Medication Class: Phosphodiesterase-5 inhibitor (PDE-5 inhibitor)
Manufacturer: Pfizer
Approval Date: March 1998

Viagra increases blood flow to the penis (leading to improved erection) by inhibiting the activity of an enzyme called phosphodiesterase-5 (PDE-5).

What is Viagra used for

• Erectile dysfunction (ED)--- impotence
• Viagra for women: Although it is not approved for women, Viagra is sometimes used by women with difficulty achieving orgasm.

How effective is Viagra

• Effective within 30-60 minutes and lasts up to 4 hours
• Viagra 25, 50, and 100 mg improved erection in 63%, 74%, and 82% of patients, respectively. Only 24% of patients on placebo achieved improvement in erection.
• Viagra versus Cialis: Viagra works within 30-60 minutes and lasts 4 hours. Cialis works within 15-30 minutes and lasts 36 hours. Cialis can also be used daily without regard to sexual activity. Viagra is only used as needed depending on sexual activity.

What are interesting facts about Viagra

• First approved phosphodiesterase-5 inhibitor
• Also used for treating pulmonary arterial hypertension (Revatio)
• Effective in a broad range of patients with erectile dysfunction (e.g., diabetes, prostatectomy, TURP, depression, spinal cord injury, erectile dysfunction caused by antidepressants or antihypertensives)
• Viagra was initially developed for treating heart conditions and erection was a side effect that was noticed during its evaluation for heart disease.

What is the dosage of Viagra

Viagra pills are 25, 50, or 100 mg. 25-100 mg by mouth one hour before sexual activity. Fatty meals reduce the absorption of Viagra. Viagra did not increase the blood pressure reducing effect of alcohol.

What are the side effects of Viagra

Common: headache, flushing, nose bleed, dizziness, diarrhea, insomnia

Serious: Low blood pressure, heart attack, stroke, vision or hearing loss, seizures, sudden death, priapism, Non Arteritic Ischemic Optic Neuropathy (NAION)

Viagra drug interactions

• Other PDE5 inhibitors (Revatio, Cialis, Levitra)
• Isosorbide mononitrate (Imdur), isosorbide dinitrate (Isordil), nitroglycerin (Nitro-Dur, Transderm-Nitro)
• Itraconazole (Sporanox)
• Erythromycin
• Ketoconazole (Nizoral)
• Cimetidine (Tagamet)
• HIV protease inhibitors (e.g, Norvir)
• Boceprivir (Victrelis)
• Telaprivir (Incivek)
• Rifampin
• Bosetan (Tracleer)
• Alpha blockers (e.g., Hytrin, Cardura)
• Grapefruit juice 

What is the price of Viagra

$13.95 to $51 per tablet

How to obtain prescription assistance for Viagra

For prescription assistance for Viagra visit Pfizer Prescription Program.

References: Viagra FDA Prescribing Information

This medication summary is for information only and is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider.

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