viagra on line
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viagra on line , an oral therapy for erectile dysfunction, is the citrate salt of sildenafil,
a selective
inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase
type 5 (PDE5).
Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1Hpyrazolo[
4,3-d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine citrate and
has the
following structural formula:
viagra on line ( Sildenafil citrate )is a white to off-white crystalline powder with
a solubility of 3.5 mg/mL in
water and a molecular weight of 666.7. viagra on line (sildenafil citrate) is formulated
as blue,
film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100
mg of
viagra on line sildenafil for oral administration. In addition to the active ingredient,
viagra on line 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.
CLINICAL PHARMACOLOGY
viagra on line Mechanism of Action
The physiologic mechanism of erection of the penis involves release of nitric
oxide (NO) in the
corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate
cyclase,
which results in increased levels of cyclic guanosine monophosphate (cGMP),
producing smooth
muscle relaxation in the corpus cavernosum and allowing inflow of blood. viagra on line
Sildenafil has no
direct relaxant effect on isolated human corpus cavernosum, but enhances the
effect of nitric
oxide (NO) by inhibiting phosphodiesterase type 5 (PDE5), which is responsible
for degradation
of cGMP in the corpus cavernosum. When sexual stimulation causes local release
of NO,