What are the recommended doses of tadalafil (phosphodiesterase type 5 inhibitor) for erectile dysfunction?

Recommended Dosing of Tadalafil for Erectile Dysfunction

For erectile dysfunction, tadalafil can be prescribed as either 10 mg taken as needed (which may be adjusted to 5-20 mg based on efficacy and tolerability) or as a daily dose starting at 2.5 mg (which may be increased to 5 mg). 1

As-Needed Dosing

• The recommended starting dose is 10 mg taken prior to anticipated sexual activity 1
• The dose may be increased to 20 mg or decreased to 5 mg based on individual efficacy and tolerability 1
• Maximum recommended dosing frequency is once per day 1
• Tadalafil improves erectile function for up to 36 hours following dosing 1
• In clinical trials, 69% of men using tadalafil as needed reported successful sexual intercourse attempts compared to 33% with placebo 2

Once-Daily Dosing

• The recommended starting dose for once-daily use is 2.5 mg, taken at approximately the same time every day 1
• The dose may be increased to 5 mg based on individual efficacy and tolerability 1
• Daily dosing eliminates the need to time medication with sexual activity 2
• Daily tadalafil (5 mg) has been shown to be well-tolerated and significantly improve erectile function in men with ED 3
• Daily use provides an alternative for couples who prefer spontaneous rather than scheduled sexual activity 2

Special Populations and Considerations

Renal Impairment

• For as-needed use in patients with creatinine clearance 30-50 mL/min:
  • Starting dose of 5 mg not more than once per day
  • Maximum dose of 10 mg not more than once every 48 hours 1
• For as-needed use in patients with creatinine clearance <30 mL/min or on hemodialysis:
  • Maximum dose of 5 mg not more than once every 72 hours 1
• For once-daily use in patients with creatinine clearance <30 mL/min or on hemodialysis:
  • Not recommended 1

Hepatic Impairment

• For mild to moderate hepatic impairment (Child-Pugh Class A or B):
  • Dose should not exceed 10 mg once per day 1
• For severe hepatic impairment:
  • Use of PDE5i is generally not recommended 2

Other Considerations

• Tadalafil may be taken without regard to food 1
• Sexual stimulation is necessary for the medication to be effective 2
• More than one trial with the medication may be required to establish efficacy 2
• Incorrect use (lack of sexual stimulation, medication taken with a large meal) accounts for a large percentage of treatment failures 2
• Men with diabetes and men who are post-prostatectomy have more severe ED at baseline and may respond less robustly to PDE5 inhibitors 2

Efficacy and Safety

• High-quality evidence shows that tadalafil significantly improves erectile function compared to placebo 2
• The most common adverse events include dyspepsia, headache, back pain, nasal congestion, and myalgia 2
• Tadalafil has lower rates of flushing compared to other PDE5 inhibitors 2
• Long-term studies show that tadalafil 5 mg dosed once daily is well-tolerated and effective for up to 2 years 4
• Daily use of 2.5 mg and 5 mg tadalafil for 12 weeks has been shown to be well-tolerated and significantly improve erectile dysfunction 3

Combination Therapy

• For men with ED and testosterone deficiency, combining tadalafil with testosterone therapy may be more effective than tadalafil alone 2
• Testosterone therapy alone is not an effective monotherapy for ED 2

Clinical Pearls

• Titrate doses to find the optimal balance between efficacy and side effects 2
• The pharmacodynamic effect of tadalafil 20 mg can begin as early as 16 minutes after dosing 5
• Daily tadalafil (10/20 mg) has been shown to be effective in men who previously did not respond to on-demand tadalafil 6
• Tadalafil is contraindicated in patients taking oral nitrates due to risk of significant hypotension 2