Katora (Sildenafil Citrate)

Sildenafil citrate works on the nitric‑oxide/cGMP pathway to treat conditions that benefit from vascular smooth‑muscle relaxation.

• Erectile dysfunction: enhances blood flow to the corpus cavernosum, helping men achieve and sustain an erection adequate for satisfactory sexual performance.
• Pulmonary arterial hypertension: reduces pulmonary vascular resistance, leading to decreased arterial pressure and improved capacity for physical activity in affected patients.

• Sildenafil citrate inhibits the phosphodiesterase type 5 enzyme, preventing the breakdown of cyclic guanosine monophosphate (cGMP) in smooth‑muscle cells. Elevated cGMP causes relaxation of vascular smooth muscle, especially in the corpus cavernosum and pulmonary arteries, thereby increasing blood flow during sexual stimulation and lowering pulmonary arterial pressure.

Sildenafil citrate may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache
• Flushing
• Indigestion or dyspepsia
• Nasal congestion
• Visual disturbances (e.g., blue‑tinted vision)

Serious or Rare Side Effects

• Priapism lasting more than 4 hours
• Sudden loss of vision (non‑arteritic anterior ischemic optic neuropathy)
• Sudden hearing loss
• Severe hypotension or cardiovascular events

Before prescribing Katora, clinicians should consider several safety factors.

• Cardiovascular assessment: evaluate for underlying heart disease before prescribing.
• Nitrate contraindication: avoid concurrent use with nitrates or nitric‑oxide donors.
• Hepatic impairment: use with caution in severe liver dysfunction.
• Visual monitoring: advise patients to report sudden vision changes promptly.
• Blood pressure monitoring: watch for significant drops in blood pressure.
• Store at ambient temperature: keep tablets in the original container, protect from moisture and heat.

Sildenafil citrate can interact with several medicines; some combinations should be avoided while others require monitoring.

Major Interactions (Avoid)

• Nitrates (e.g., nitroglycerin): can cause severe hypotension.
• Guanylate cyclase stimulators (e.g., riociguat): additive vasodilatory effect.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): increase sildenafil plasma levels.

Moderate Interactions (Monitor Closely)

• Alpha‑blockers (e.g., doxazosin): may enhance blood‑pressure lowering.
• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce efficacy.
• Other PDE5 inhibitors (e.g., tadalafil) taken together: risk of additive adverse effects.
• Antihypertensive agents: monitor for excessive hypotension.