VEETAB Tablet

For the treatment of erectile dysfunction.

Dosage and Administration

For most patients, the recommended dose is 50mg taken, as needed, approximately1 hour before sexual activity. However, sildenafil citrate may be taken anywhere from 0.5 hour to 4 hours before sexual activity. Based on effectiveness and toleration, the dosage may be increased to a maximum recommended dose of 100mg or decreased to 25mg. The maximum recommended dosing frequency is once per day.

Consistent with its known effects on the nitric oxide/cQMP pathway sildenafil citrate was shown to potentiate the hypotensive effects of nitrates, and potentiate the hypotensive effects of nitrates, and its administration to patients who are using organic nitrates either regularly and/or intermittently in any form is therefore contraindicated. Sildenafil citrate is contraindicated in patients with a known hypersensitivity to any component of the tablet.

Sildenafil citrate is not indicated for use in newborns, children, or women.

The most common side effects of sildenafil citrate are headache, flushing of the face, and upset stomach. Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light, or blurred vision. Heart attack, stroke, irregular heartbeats, and death have been reported rarely in men taking sildenafil citrate. Most, but not all, of these men had heart problems before taking this medicine.

Single doses of antacid (magnesium hydroxide/ aluminum hydroxide) did not affect the bioavailability of sildenafil citrate.

Sildenafil metabolism is principally mediated by the CYP450 isoforms 3A4 (major route) and 2C9 (minor route). Therefore, inhibitors of these isoenzymes may reduce sildenafil clearance.

Cimetidine (800mg), a nonspecific CYP inhibitor

Erythromycin

Contraindicated.

The safety of sildenafil citrate is unknown in patients with bleeding disorders and patients with active peptic ulceration.

The safety and efficacy of combinations of sildenafil citrate with other treatments for erectile dysfunction have not been studied. Therefore, the use of such combinations is not recommended.

Sildenafil has no direct relaxant effect on isolated human corpus cavernosum, but enhances the effect of nitric oxide (NO) by inhibiting phosphodiesterase type 5 (PED5), which is responsible for degradation of cQMP in the corpus cavernosum. When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil causes increased levels of cQMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. Sildenafil at recommended doses has no effect in the absence of sexual stimulation.