What is the recommended dosing for Cialis (tadalafil) in patients with erectile dysfunction?

Tadalafil Dosing for Erectile Dysfunction

For patients with erectile dysfunction, the recommended starting dose of tadalafil is 10 mg taken prior to anticipated sexual activity, which can be increased to 20 mg or decreased to 5 mg based on individual efficacy and tolerability. 1

As-Needed Dosing

• Tadalafil can be taken as needed with a maximum recommended dosing frequency of once per day 1
• The medication improves erectile function for up to 36 hours following dosing, allowing flexibility in timing of sexual activity 1, 2
• No food restrictions are necessary; tadalafil may be taken without regard to meals 1
• The entire tablet should be taken without splitting 1
• High-quality evidence shows that tadalafil significantly improves erectile function compared to placebo, with 75% of intercourse attempts successfully completed with 20 mg tadalafil versus placebo 3

Once-Daily Dosing Option

• For patients preferring daily use, the recommended starting dose is 2.5 mg taken at approximately the same time every day 1
• The daily 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, providing an alternative for couples who prefer spontaneous rather than scheduled sexual activity 4, 5
• Once-daily tadalafil (5 mg or 10 mg) has been shown to be well tolerated and significantly improves erectile function in men with ED 5

Dose Adjustments for Special Populations

Renal Impairment

• For creatinine clearance 30-50 mL/min:
  • As-needed use: Starting dose of 5 mg not more than once per day, maximum dose 10 mg not more than once every 48 hours 1
  • Daily use: Starting dose of 2.5 mg, may increase to 5 mg based on individual response 1
• For creatinine clearance less than 30 mL/min or on hemodialysis:
  • As-needed use: Maximum dose 5 mg not more than once every 72 hours 1
  • Daily use: Not recommended 1

Hepatic Impairment

• Mild to moderate impairment (Child-Pugh Class A or B): Dose should not exceed 10 mg once per day 1
• Severe impairment (Child-Pugh Class C): Use of tadalafil is not recommended 1

Efficacy Considerations

• Improvement in erectile function with tadalafil is not dose-dependent between 5-20 mg, unlike sildenafil and vardenafil where higher doses show greater efficacy 6, 4
• Approximately 81% of patients report improved erections with tadalafil 20 mg compared to 35% with placebo 3
• Tadalafil is effective across all age groups and ED severity levels 3
• About 62% of patients treated with tadalafil 20 mg achieve successful sexual intercourse after their first dose 7

Safety and Tolerability

• The most common adverse events include headache (15.8%), dyspepsia (11.8%), back pain (8.2%), and myalgia 8, 4
• Tadalafil has lower rates of flushing compared to other PDE5 inhibitors 4
• Long-term studies show tadalafil is safe and well-tolerated for up to 24 months of use 8
• Tadalafil is contraindicated in patients taking oral nitrates due to risk of significant hypotension 4

Clinical Pearls

• Sexual stimulation is necessary for tadalafil to be effective; incorrect use accounts for a large percentage of treatment failures 4
• Men with diabetes or post-prostatectomy may have more severe ED at baseline and may respond less robustly to PDE5 inhibitors 4, 9
• For men with ED and testosterone deficiency, combining tadalafil with testosterone therapy may be more effective than tadalafil alone 4
• Most patients taking tadalafil attempt sexual intercourse at least once at 12-36 hours after dosing, taking advantage of the medication's extended duration of action 2