Sildenafil is the non-proprietary name for the active ingredient in Viagra, an erectile dysfunction (ED) treatment for men.

While Viagra is by far the most widely-recognized of Sildenafil products, Sildenafil is found in a wide range of generic alternatives. It is also found in some other formulations, such as Viagra Oral Jelly.

Sildenafil is a phosphodiesterase 5 inhibitor (PDE5 inhibitor) which works as a vasodilator, improving blood flow. While a very effective treatment for ED, it does pose risk of side effects for some men who have other medical conditions or who take certain other medications.

Sildenafil has no known use in women and should not be used by young men who haven't yet reached sexual maturity.

Taking Sildenafil

In tablet form, Sildenafil should be taken 30 to 45 minutes before intimacy. In most men effects peak 2 hours after administration before gradually tapering off, and are usually gone completely after 5 or 6 hours. There is some slight variation according to individual response as well as dosage strength.

Tablets can be taken with or without food according to personal preference. Taking with a heavy meal may make the medication somewhat less effective.

Even after Sildenafil starts working, some sexual stimulation is required for an erection to form; the medication is not an aphrodisiac.

Treatment usually looks like:

• Otherwise healthy men are usually started on 50 mg Sildenafil.
• If 50 mg is ineffective, dosage may be increased to 100 mg.
• If side effects are experienced with 50 mg, dosage may be reduced to 25 mg.
• Men who have certain other medical conditions or take certain other medications may be started on 25 mg instead of 50 mg.
• Do not exceed 200 mg in a single dose without explicit doctor approval.
• Do not take more than one dose of Sildenafil in a 24 hour period.

As mentioned above, Sildenafil begins working after about 30 minutes and effects last 4 to 6 hours, during which time intercourse should be possible.

Men who haven't taken Sildenafil before should be aware that the medication doesn't always produce significant results the first few times it's used. Assuming no side effects develop, give the medication a few tries before deciding it doesn't work.

Precautions & Side Effects

Men with a history of the following should be sure to discuss risks and warning signs with a doctor before taking Sildenafil:

• Significantly low or high blood pressure
• Heart, liver or kidney problems
• Any blood cell or bleeding disorders
• Any vision or hearing disorders
• Penile implants or physical abnormalities

Men with the above may be started on lower doses of 25 mg, or may be told to avoid the medication altogether.

Similarly, if taking certain other medications, the initial dosage may be lower:

• Other ED treatments
• Nitrites or nitrates
• Protease inhibitors
• Alpha-blockers
• High blood pressure treatments
• Antibiotics
• Antifungal medications
• Guanylate cyclase stimulators

The above medications are concerning, but are not the only medications that can interact with Sildenafil. Always double-check with a doctor or pharmacist before mixing treatments.

Otherwise healthy men rarely experience side effects, and when they do occur they're typically mild. Most commonly reported are:

• Headache
• Mild muscle aches
• Mild stomach upset
• Cold-like symptoms

Though rare, Sildenafil products are associated with vision impairment, including blurry vision, seeing a blue halo or tint, and light sensitivity. These symptoms typically reverse when the medication wears off. Even more rarely vision loss or hearing loss occurs; this may or may not be reversible. Stop taking Sildenafil if any vision or hearing symptoms develop.