Tadalafil Dosing for Erectile Dysfunction
For erectile dysfunction, tadalafil can be prescribed as either 10 mg taken as needed prior to sexual activity (with dose adjustments to 5-20 mg based on efficacy and tolerability) or as a daily regimen starting at 2.5 mg with possible increase to 5 mg. 1
On-Demand Dosing Regimen
- Starting dose: 10 mg taken prior to anticipated sexual activity 1
- Dose adjustment: May be increased to 20 mg or decreased to 5 mg based on individual response and side effects 1
- Maximum frequency: Once per day in most patients 1
- Timing: Can be effective up to 36 hours following dosing, providing flexibility for sexual activity 1, 2
- Food interactions: May be taken without regard to food 1
Daily Dosing Regimen
- Starting dose: 2.5 mg taken at approximately the same time every day 1
- Dose adjustment: May be increased to 5 mg based on efficacy and tolerability 1
- Timing: Taken without regard to timing of sexual activity 1
- Benefit: Daily dosing provides sustained therapeutic levels and allows for more spontaneous sexual activity 3, 4
Special Population Considerations
Renal Impairment
- Moderate impairment (CrCl 30-50 mL/min):
- Severe impairment (CrCl <30 mL/min):
Hepatic Impairment
- Mild to moderate impairment (Child-Pugh Class A or B): Maximum 10 mg once per day 1
- Severe impairment (Child-Pugh Class C): Not recommended 1
Efficacy Considerations
- Tadalafil has been shown to improve erectile function compared to placebo for up to 36 hours following dosing 1, 2
- In clinical trials, both 5 mg and 10 mg daily dosing significantly improved erectile function compared to placebo 4
- Approximately 52% of men taking tadalafil 20 mg had successful intercourse within 30 minutes of dosing compared to 35% on placebo 6
- Tadalafil may be preferred by some patients over other PDE5 inhibitors due to its longer duration of action 7
Safety and Monitoring
- Most common adverse events include headache (15.8%), dyspepsia (11.8%), nasopharyngitis (11.4%), and back pain (8.2%) 8
- Absolute contraindication: Concomitant use with nitrates due to risk of severe hypotension 3, 5
- Patients should be instructed that sexual stimulation is necessary for the medication to work 3, 5
- Long-term safety studies support the use of tadalafil for up to 24 months 8
Practical Considerations
- Patients should be informed that the entire tablet should be taken (not split) 1
- For patients who fail to respond to tadalafil, consider checking for proper medication use, hormonal abnormalities, or relationship issues before changing therapy 5
- For patients with diabetes or post-prostatectomy, be aware that they may have more severe ED at baseline and may respond less robustly to PDE5 inhibitors 3, 5
By following these dosing guidelines and considering patient-specific factors, tadalafil can be effectively used to treat erectile dysfunction while minimizing adverse effects and maximizing quality of life.