From the Guidelines
Sildenafil is recommended as the first-line treatment for erectile dysfunction, with a starting dose of 50mg taken approximately one hour before sexual activity, as it has been shown to significantly improve erectile function and sexual intercourse in patients with ED 1. The dose can range from 25mg to 100mg, taken no more than once daily, with adjustments possible based on effectiveness and tolerability.
- Lower starting doses (25mg) are recommended for men over 65, those with liver or severe kidney impairment, or patients taking certain medications like protease inhibitors.
- Sildenafil works by enhancing blood flow to the penis by inhibiting phosphodiesterase type 5 (PDE5), which breaks down cGMP, a chemical that relaxes smooth muscles in blood vessels.
- The medication should be taken on an empty stomach or after a light meal for optimal absorption, as high-fat meals can delay its effectiveness.
- Patients should be aware that sexual stimulation is still required for the medication to work, and common side effects may include headache, flushing, indigestion, nasal congestion, and visual disturbances.
- Sildenafil is contraindicated in patients taking nitrates for heart conditions as this combination can cause dangerous drops in blood pressure, as noted in the clinical practice guideline from the American College of Physicians 1. Key considerations for the choice of a specific PDE-5 inhibitor, such as sildenafil, include individual patient preferences, ease of use, cost of medication, and adverse effects profile, although the evidence for these factors is considered low-quality 1. It is also important to note that improvement in erectile function was related to higher doses for sildenafil, but higher doses were associated with a greater risk for an adverse effect 1.
From the Research
Recommended Treatment and Dosage for Erectile Dysfunction using Sildenafil
- The recommended starting dose for sildenafil is 50mg, taken as needed, approximately 1 hour before sexual activity, with a maximum dose of 100mg once daily 2.
- Lower doses, such as 25mg, may be used in elderly patients, those with hepatic or renal impairment, or patients receiving certain medications, such as ritonavir, saquinavir, ketoconazole, erythromycin, or cimetidine 2.
- Sildenafil has been shown to be effective in improving erections and allowing successful penetrative sexual intercourse in men with erectile dysfunction of various causes, including organic, psychogenic, and mixed origins 2, 3, 4.
- The efficacy of sildenafil is not affected by patient age, and it has been shown to be effective in men aged 65 years and older, as well as those aged 75 years and older 5.
Efficacy and Safety of Sildenafil
- Sildenafil has been shown to be effective in improving erection quality, treatment satisfaction, and reducing anxiety levels in men with erectile dysfunction 3, 4.
- Common adverse events associated with sildenafil are transient and mild or moderate, and include headache, flushing, dyspepsia, nasal congestion, and abnormal vision 2, 6, 5.
- Sildenafil has been shown to be well-tolerated in long-term studies, with no serious sildenafil-related adverse events occurring in clinical trials 2, 4.
Comparison with Other Phosphodiesterase Inhibitors
- Sildenafil has been compared to other phosphodiesterase inhibitors, such as vardenafil and tadalafil, and has been shown to be similarly effective in the treatment of erectile dysfunction 6.
- Tadalafil has a longer duration of action than sildenafil and vardenafil, and may be preferred by some men with erectile dysfunction due to its longer duration of action 6.