Manufacturer: Ajanta Pharma
Pharmaceutical name: Sildenafil Citrate
Pack: 1 tab (100 mg/tab)

VIAGRA is indicated for the treatment of erectile dysfunction.

Therapeutic actions: The physiologic mechanism of erection of the penis involves release of nitric oxide in the corpus cavernosum during sexual stimulation. Nitric oxide 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. Sildenafil has no direct relaxant effect on isolated human corpus cavernosum, but enhances the effect of nitric oxide by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cGMP in the corpus cavernosum. When sexual stimulation causes local release of nitric oxide, inhibition of PDE5 by sildenafil causes increased levels of cGMP 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.

What is it used for?:
- erection disorder, described by inability to achievement or preservation of penis erection, sufficient for the satisfactory sexual congress. Sildenafil is effective only at presence of sexual stimulation.

Contraindications and cautions: Before taking sildenafil, tell your doctor if you are allergic to any drugs, or if you have:
- heart disease or heart rhythm problems;
- a recent history (in the past 6 months) of a heart attack, stroke, or heart rhythm disorder;
- congestive heart failure;
- high or low blood pressure;
- coronary artery disease;
- liver disease;
- kidney disease;
- a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;
- a bleeding disorder such as hemophilia;
- a stomach ulcer;
- retinitis pigmentosa (an inherited condition of the eye);
- a physical deformity of the penis (such as Peyronie's disease); or
- if you have been told you should not have sexual intercourse for health reasons.

Side effects: General: Diarrhea; flushing; headache; heartburn; stuffy nose; mild, temporary vision changes (eg, blurred vision, sensitivity to light, blue/green color tint to vision); dizziness; upset stomach. Serious allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; fainting; fast or irregular heartbeat; painful or prolonged erection; ringing in the ears; seizure; severe or persistent dizziness; severe or persistent vision changes; sudden decrease or loss of vision in one or both eyes; sudden hearing loss.

Interactions:
- Alpha-blockers (eg, doxazosin), amlodipine, medicines for high blood pressure, nitrates (eg, isosorbide, nitroglycerin), or nitroprusside because severe low blood pressure with dizziness, lightheadedness, and fainting may occur
- Azole antifungals (eg, itraconazole), cimetidine, H2 agonists (eg, famotidine), HIV protease inhibitors (eg, ritonavir), macrolide antibiotics (eg, erythromycin), or telithromycin because they may increase the risk of Viagra 's side effects
- Bosentan or rifampin because they may decrease Viagra 's effectiveness