Sildenafil 50 mg – General Information
| Feature | Detail |
|--------|--------|
| Drug class | Phosphodiesterase‑type‑5 (PDE‑5) inhibitor |
| Common brand names | Viagra®, Revatio® (for pulmonary arterial hypertension), others |
| Typical dose for erectile dysfunction (ED) | 25 mg–100 mg taken orally 30–60 min before sexual activity. The 50 mg strength is a common starting dose for many patients. |
| Typical dose for pulmonary arterial hypertension (PAH) | 40 mg taken three times per day (Revatio®). |
| Administration | Oral tablet, with or without food (food may delay onset by ~30 min). |
| Duration of action | Peak effect 1–2 h; therapeutic window up to 4–5 h. |
---
How It Works
Sildenafil blocks the breakdown of cyclic guanosine monophosphate (cGMP) in the smooth muscle of the corpus cavernosum. This causes relaxation of vascular smooth muscle and increased blood flow to the penis, which helps achieve and maintain an erection when sexual stimulation occurs.
---
Common Side Effects
- Headache
- Flushing (redness)
- Dyspepsia (indigestion)
- Nasal congestion
- Back pain
- Visual disturbances (blue‑tinged vision, increased sensitivity to light)
These are usually mild and transient. If you experience severe visual changes (e.g., blurred vision, loss of vision) or any signs of an allergic reaction (rash, itching, swelling, difficulty breathing), seek medical help immediately.
---
Serious (but rare) Risks
- Priapism (erection >4 h): Stop the drug and seek immediate medical attention; this is an emergency.
- Severe hypotension (especially with nitrate‑containing drugs): Do not take sildenafil if you use nitrates for angina or heart failure.
- Vision loss (non‑arteritic anterior ischemic optic neuropathy): Rare but can be permanent; notify a healthcare provider if you notice sudden vision changes.
- Cardiovascular events (heart attack, stroke): Use with caution in patients with significant cardiovascular disease; always discuss your medical history with a clinician.
---
Contraindications
- Concurrent use of nitroglycerin or other nitrate drugs
- Severe hepatic or renal impairment (dose adjustments or avoidance may be required)
- Known hypersensitivity to sildenafil or any excipients
- Recent or planned use of strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) or strong CYP3A4 inducers (e.g., rifampin)
---
Drug Interactions (Key Points)
| Class | Example | What to watch for |
|-------|---------|-------------------|
| Nitrates | Nitroglycerin, isosorbide mononitrate | Severe, potentially fatal hypotension |
| Strong CYP3A4 inhibitors | Ketoconazole, clarithromycin, ritonavir | ↑Sildenafil levels → ↑risk of side effects |
| Strong CYP3A4 inducers | Rifampin, carbamazepine | ↓Sildenafil levels → ↓effectiveness |
| Other PDE‑5 inhibitors | Tadalafil, vardenafil | Cumulative hypotension |
| Alcohol | Excessive drinking | Heightened dizziness, hypotension |
| Antihypertensives (ACE inhibitors, ARBs, beta‑blockers) | Lisinopril, losartan | Potential additive blood‑pressure lowering |
Always inform your prescriber of all medications, supplements, and herbal products you are taking.
---
Special Populations
| Group | Guidance |
|-------|----------|
| Elderly | Use the lowest effective dose; monitor for hypotension, dizziness, or fainting. |
| Pregnancy | Not recommended; insufficient safety data. |
| Lactation | Limited data; generally not recommended. |
| Children | Not approved for use in pediatric patients except for PAH (Revatio® in specific age ranges). |
---
What to Do If You Miss a Dose
Sildenafil is taken as needed for ED; it does not accumulate. If you forget to take a dose, skip it and take the next dose at the usual time. Do not double‑dose.
---
When to Seek Medical Help
- Persistent erection >4 h (priapism)
- Sudden vision changes or loss
- Chest pain, shortness of breath, or severe headache
- Severe hypotension (symptoms: dizziness, fainting, rapid heartbeat)
---
Bottom Line
- 50 mg is a standard starting dose for most adults with erectile dysfunction.
- It should be taken under the guidance of a healthcare provider.
- Use only as prescribed; do not self‑medicate, especially if you have cardiovascular disease or take nitrates.
- Monitor for common side effects; seek prompt care for serious symptoms.
---
Disclaimer:
This information is for general educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.