02. SILDENAFIL CITRATE
Sildenafil citrate is used for treating erectile dysfunction and pulmonary arterial hypertension.
Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine citrate and has the following structural and chemical formula is C22H30N6O4S.
VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100 mg of sildenafil for oral administration. In addition to the active ingredient, sildenafil citrate, each tablet contains the following inactive ingredients: microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, magnesium stearate, hypromellose, titanium dioxide, lactose, triacetin, and FD & C Blue #2 aluminum lake.
What are the possible side effects of oral sildenafil?
The most common side effects include headaches, nasal congestion, impaired vision, photophobia, and dyspepsia. Less commonly, some users experienced cyanopsia (everything had a tinted blue tinge).
In very rare cases it can lead to vision impairment and nonarteritic anterior ischemic optic neuropathy.
Postmarketing surveillance side effects have included (very rare) priapism, heart attack, sudden hearing loss, increased intraocular pressure, and ventricular arryhythmias.
Viagra can decrease blood supply to the optic nerve, causing sudden vision loss. This very rare adverse event occurred mainly to patients who had heart disease, hypertension, diabetes, high cholesterol, or pre-existing eye problems. Nobody really knows whether the vision loss was caused by the Viagra.
Do NOT use sildenafil if:
- you are allergic to any ingredient in sildenafil
- you have pulmonary veno-occlusive disease (PVOD)
- you are taking nitrates (eg, isosorbide, nitroglycerin) in any form (eg, tablet, capsule, spray, patch, ointment) or nitroprusside
- you take another medicine that contains sildenafil, another PDE5 inhibitor (eg, tadalafil, vardenafil), or ritonavir
- you use certain recreational drugs called "poppers" (eg, amyl nitrate or nitrite, butyl nitrate or nitrite)
- Contact your doctor or health care provider right away if any of these apply to you.