Viagra or sildenafil is a popular drug on the market for use in the management of erectile dysfunction or inability to initiate or maintain an erection. It is not indicated for use in women. Viagra is manufactured in three dosages: 25 mg, 50 mg and 100 mg tablets. Adverse effects range from headache and dizziness to dyspepsia and diarrhea.
Erectile Dysfunction
VIAGRA is known to result in harder and longer erections compared to placebo. The result increases with increasing dose and concentration in the blood.VIAGRA results in an effective erection for four hours, although the erection diminished after two hours, according to the drug information from Pfizer.com. Infrequently, urinary incontinence, abnormal ejaculation, genital swelling and anorgasmia or inability to have orgasm occurs.
Effects on Blood Pressure
Single doses of VIAGRA by mouth causes a decrease in blood pressure while sitting, most notable one to two hours after taking. The effect on blood pressure is similar for the 25mg, 50mg and 100mg tablet. This shows that the effect on blood pressures is not dose related. Patients who take nitrates, like nitroglycerin or isosorbide dinitrate, among others experienced more significant blood pressure reduction, according to Pfizer.
Effect on Vision
Short term impairment of color discernment occurred at oral doses of 100mg and 200mg as a result of the disruption of phototransduction in the retina. VIAGRA did not affect visual acuity, pressures on the inside of the eye or pupil function. It does, however, cause increased light sensitivity, though no more than does placebo.
