Silagra 50 Tab

What is Silagra?

Silagra is a brand of Sildenafil Citrate, a selective, reversible inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), used to treat erectile dysfunction and pulmonary arterial hypertension.

Indications

Treatment of men with erectile dysfunction (the inability to achieve or maintain a penile erection sufficient for satisfactory sexual performance); sexual stimulation is required for Silagra to be effective. Also indicated in pulmonary arterial hypertension.

Pharmacology

Erection involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation, which activates guanylate cyclase, increasing cGMP and producing smooth muscle relaxation and inflow of blood. Sildenafil enhances the effect of NO by inhibiting PDE5, the enzyme responsible for cGMP degradation in the corpus cavernosum, with no effect in the absence of sexual stimulation. Sildenafil is rapidly absorbed orally (mean absolute bioavailability 41%), eliminated predominantly by hepatic CYP3A4 metabolism, with a terminal half-life of about 4 hours.

Dosage & Administration

Erectile dysfunction: For most patients the recommended dose is 50 mg taken as needed approximately 1 hour before sexual activity (effective range 0.5-4 hours before). Dose may be increased to a maximum of 100 mg or decreased to 25 mg based on effectiveness and tolerability. Maximum dosing frequency is once per day. A starting dose of 25 mg should be considered in patients over 65, with hepatic or severe renal impairment, or on potent CYP3A4 inhibitors.

Pulmonary arterial hypertension: 20 mg three times daily, approximately 4-6 hours apart, with or without food.

Interaction

Metabolism is mediated principally by CYP3A4 and CYP2C9. CYP3A4 inhibitors (ketoconazole, itraconazole, erythromycin, ritonavir, saquinavir, cimetidine) increase plasma Sildenafil levels; CYP3A4 inducers (e.g. rifampin, bosentan) decrease levels. No significant interaction with antacids, CYP2C9/2D6 inhibitors, thiazide diuretics, ACE inhibitors, or calcium channel blockers.

Contraindications

Hypersensitivity to any component. Contraindicated with regular or intermittent use of organic nitrates due to potentiated hypotensive effects.

Side Effects

Commonly reported: headache, flushing, dyspepsia, nasal congestion, visual disturbances, dizziness. Less common but serious: prolonged erection, priapism, sudden vision or hearing loss, myocardial infarction, arrhythmia, and other cardiovascular events (often associated with pre-existing cardiovascular risk factors).

Pregnancy & Lactation

Pregnancy Category B. Sildenafil is not indicated for use by women; no adequate well-controlled studies exist in pregnant women.

Precautions & Warnings

Caution when co-administered with alpha-blockers due to additive blood-pressure-lowering effects. Use with caution in patients with anatomical penile deformation, conditions predisposing to priapism (e.g. sickle cell anemia), bleeding disorders, or active peptic ulceration. Not recommended for patients for whom sexual activity is inadvisable due to underlying cardiovascular status. Seek immediate medical help for an erection lasting more than 4 hours.

Overdose Effects

Adverse events at higher doses are similar to those at lower doses but with increased incidence/severity. Standard supportive measures should be used; renal dialysis does not accelerate clearance as Sildenafil is highly protein-bound.

Therapeutic Class

Drugs for Erectile Dysfunction

Storage Conditions

Keep in a dry place, away from light and heat. Keep out of the reach of children.