Sildenafil Citrate: Uses, Dosage, Side Effects | MedexInfo
Sildenafil Citrate
Rx
Generic NameSildenafil Citrate
Therapeutic ClassPDE5 Inhibitor
Common Strength25 mg, 50 mg, 100 mg tablets
Max / 24h100 mg per day for ED; individualized for PAH
PregnancyNot intended for use in women
Indications ▼
Erectile Dysfunction (ED): Treatment of ED in adult men to improve erectile function by enhancing penile blood flow in response to sexual stimulation.
Pulmonary Arterial Hypertension (PAH): Used in adults to improve exercise capacity and delay clinical worsening by reducing pulmonary vascular resistance.
Mechanism & Pharmacokinetics ▼
Mechanism: Sildenafil inhibits phosphodiesterase type 5 (PDE5), preventing the breakdown of cyclic GMP (cGMP) in the corpus cavernosum and pulmonary vasculature. This leads to smooth muscle relaxation, vasodilation, and increased blood flow.
Pharmacokinetics: Rapidly absorbed orally; peak plasma levels in 30–120 minutes. Metabolized primarily by CYP3A4 and CYP2C9. Half-life ~4 hours. Excreted mostly as metabolites in feces and urine.
Dosage & Administration ▼
| Indication | Dose | Frequency |
|---|---|---|
| Erectile Dysfunction | 50 mg (initial) | As needed, 30–60 minutes before sexual activity, max 100 mg/day |
| Pulmonary Arterial Hypertension | 20 mg | Three times daily |
Note: Adjust dose based on efficacy, tolerability, age, renal or hepatic impairment. Do not exceed recommended daily dose. Avoid concomitant nitrates due to risk of severe hypotension.
Side Effects ▼
Headache, flushing, dyspepsia
Nasal congestion, dizziness
Visual disturbances (blurred vision, color tinge)
Rare: priapism, sudden hearing loss, myocardial infarction
Contraindications ▼
Hypersensitivity to Sildenafil or excipients
Concurrent use of nitrates or nitric oxide donors
Severe cardiovascular disease (unstable angina, recent MI, severe hypotension)
Severe hepatic impairment or end-stage renal disease (caution; adjust dose)
Drug Interaction ▼
CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) increase plasma levels—dose adjustment may be needed.
CYP3A4 inducers (e.g., rifampin) may reduce efficacy.
Concurrent nitrates or nitric oxide donors: severe hypotension; strictly contraindicated.
Pregnancy & Lactation ▼
Not intended for use in women; limited data on safety.
Breastfeeding: use only if benefits outweigh potential risks.
Clinical / Research Summary ▼
Clinical Role: First-line therapy for ED; also used for PAH to improve exercise tolerance.
Advantage: Rapid onset, effective in most patients, well-tolerated.
Limitation: Requires sexual stimulation for ED efficacy; contraindicated with nitrates; cardiovascular caution needed.
Monitoring: Blood pressure, cardiac status, vision or hearing changes, and priapism risk.
Patient Counseling Points ▼
Take 30–60 minutes before sexual activity; not daily unless prescribed for PAH.
Avoid alcohol excess; may reduce efficacy or increase side effects.
Do not combine with nitrates or nitric oxide donors.
Report prolonged erection (>4 hours), sudden vision or hearing loss immediately.
Storage & Handling ▼
Store below 30°C
Protect from moisture and light
Keep out of reach of children
Brand Names (Bangladesh & Global) ▼
Activa 100 mg
Adegra 100 mg
Senegra 100 mg
Silagra 100 mg
Silfil 100 mg
Starfil 100 mg
Veagra 100 mg
SB-Sild 100 mg
Viagrazen 100 mg
Medical Disclaimer: For educational purposes only. Not a substitute for professional medical advice.
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