Recommended Dosing of Sildenafil for Erectile Dysfunction
The recommended starting dose of sildenafil for erectile dysfunction is 50 mg taken approximately one hour before sexual activity, with the option to adjust to 25 mg or 100 mg based on efficacy and tolerability. 1, 2
Initial Dosing Strategy
- Starting dose: 50 mg taken as needed, no more than once daily 1, 3
- Timing: Approximately 1 hour before anticipated sexual activity 1
- Dose adjustment:
Special Population Considerations
- Elderly patients (≥65 years): Consider starting at 25 mg 1, 3
- Hepatic or renal impairment: Start with 25 mg 2, 1
- Patients taking CYP3A4 inhibitors (ritonavir, saquinavir, ketoconazole, erythromycin, cimetidine): Start with 25 mg 1, 3
- Severe renal or liver disease: Generally not recommended 2
Efficacy Considerations
- In clinical trials, sildenafil 50 mg and 100 mg doses significantly improved erectile function compared to placebo 5, 6
- The 100 mg dose has been shown to improve treatment satisfaction and reduce anxiety about sexual performance compared to the 50 mg dose 5
- For men with diabetes, sildenafil remains effective but may require higher doses, with 56% of diabetic men reporting improved erections versus 10% on placebo 6
Safety and Adverse Effects
- Common side effects include headache (11%), flushing, dyspepsia (9%), nasal congestion, and visual disturbances 3, 6
- Most adverse events are transient, mild to moderate in severity 3
- Absolute contraindication: Concurrent use with nitrates due to risk of severe hypotension 2, 4, 1
Optimizing Treatment Success
- Sexual stimulation is necessary for sildenafil to work 2
- Multiple trials may be needed to establish efficacy 2
- Taking sildenafil with a large meal may delay absorption and reduce effectiveness 2
- Patients should be counseled that treatment failure may be due to:
- Inadequate dosing
- Lack of sexual stimulation
- Taking medication with food
- Heavy alcohol use 2
Follow-up and Monitoring
- Regular follow-up is recommended to assess:
- Consider testosterone testing if response is suboptimal 4
Treatment Algorithm
- Start with 50 mg taken 1 hour before sexual activity
- If inadequate response but good tolerability after 2-4 attempts, increase to 100 mg
- If side effects occur, decrease to 25 mg
- If still ineffective after proper use and dose adjustment, consider alternative treatments such as vacuum erection devices or intracavernous injections 2, 4
Remember that sildenafil is effective across all age groups and in patients with various comorbidities, though efficacy rates may be somewhat lower in diabetic patients 7.