Sildenafil is known as generic Viagra because it is not sold under the Viagra brand name. People take it in a dosage of 25, 50, or 100 milligrams (mg) per day. Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor - the standard treatment for erectile dysfunction.

The government ordered Pfizer Inc. to yank cheeky television ads that promised better sex for men taking Viagra because they failed to disclose known risks associated with the drug, according to a letter released on Monday.

Generic Viagra, like other PDE5 inhibitors, can cause a drop in blood pressure. If you take medications for blood pressure control or tend to have low blood pressure, ask your doctor if it's safe to use sildenafil. Sildenafil doesn't trigger an erection on its own, nor does it increase sexual desire.

Because 100mg is the highest dose available, you should never 'double up' on tablets or take more than one in 24 hours. Sildenafil 100mg is the highest safe dosage you can take – if it is ineffective, you should try another ED treatment.

People who took the drug sildenafil were less likely to develop Alzheimer's disease. In cultured human neurons, sildenafil enhanced growth and reduced Alzheimer's biomarkers. The findings support further investigation of sildenafil as a possible treatment for Alzheimer's disease.

Vardenafil (Levitra) is almost 10 times more biochemically potent than sildenafil, therefore a lower dose is needed to facilitate the penile erection, potentially resulting in less side effects.

The four main medicines taken by mouth for erectile dysfunction are:

• Avanafil (Stendra).
• Sildenafil (Viagra).
• Tadalafil (Cialis).
• Vardenafil.

Minor differences in packaging aside, brand name Viagra and its generic counterpart sildenafil are exactly the same medication. If you have erectile dysfunction, both medications should produce noticeable improvements in your erections and sexual performance. The key difference, as we mentioned above, is price.

However, there is a common question that many men have about the drug: does Viagra keep you hard after ejaculation? The honest answer is no – you shouldn't bet on it. However, studies do show that Sildenafil reduces the time between orgasm and your next erection.

When used in women, Viagra is thought to raise blood flow to the genitals so that there's more sensitivity and stimulation. Studies have shown that Viagra may provide a benefit for women having difficulty with sexual arousal - since it may help them respond better to sexual stimulation.

Depending on how your body metabolizes it, you may be able to get an erection several times with Viagra in your system. Viagra probably won't make you last longer in bed, though. No research has proven definitively that Viagra can increase how long you can have sex.

Cialis might be better than Viagra if having a long-lasting ED medication is important to you, but that doesn't necessarily mean it's better for everyone. The best treatment for erectile dysfunction will depend on your experience with the two drugs.