What is the recommended dosing and administration for prescribing tadalafil (Cialis) for erectile dysfunction?

Tadalafil Dosing and Administration for Erectile Dysfunction

For erectile dysfunction, tadalafil should be prescribed either as 10 mg taken prior to anticipated sexual activity (as needed) or 2.5-5 mg once daily, with dosage adjustments based on individual efficacy and tolerability. 1

As-Needed Dosing

• The recommended starting dose is 10 mg taken prior to anticipated sexual activity, which may be increased to 20 mg or decreased to 5 mg based on individual response and side effects 1
• The maximum recommended dosing frequency is once per day 1
• Tadalafil can be taken without regard to food 1
• The entire tablet should be taken without splitting 1
• Tadalafil improves erectile function for up to 36 hours following dosing, which should be considered when advising patients on optimal use 1, 2
• Sexual stimulation is necessary for tadalafil to be effective, and incorrect use accounts for a large percentage of treatment failures 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, providing an alternative for couples who prefer spontaneous rather than scheduled sexual activity 2, 3

Dosage Adjustments for Special Populations

Renal Impairment

For as-needed use:

• Creatinine clearance 30-50 mL/min: Starting dose of 5 mg not more than once per day, maximum 10 mg not more than once every 48 hours 1
• Creatinine clearance <30 mL/min or on hemodialysis: Maximum 5 mg not more than once every 72 hours 1

For once-daily use:

• Creatinine clearance 30-50 mL/min: Starting dose of 2.5 mg, may increase to 5 mg based on individual response 1
• Creatinine clearance <30 mL/min or on hemodialysis: Once-daily use is not recommended 1

Hepatic Impairment

• Mild to moderate impairment (Child-Pugh Class A or B): For as-needed use, dose should not exceed 10 mg once per day 1
• Severe impairment (Child-Pugh Class C): Tadalafil use is not recommended 1

Drug Interactions

• Concomitant use with nitrates in any form is contraindicated due to risk of significant hypotension 1
• When co-administered with alpha-blockers for ED treatment, patients should be stable on alpha-blocker therapy before initiating tadalafil, which should be started at the lowest recommended dose 1

Efficacy and Safety

• High-quality evidence shows that tadalafil significantly improves erectile function compared to placebo, with 69% of men using tadalafil reporting successful sexual intercourse attempts compared to 33% with placebo 2, 4
• The most common adverse events include dyspepsia, headache, back pain, nasal congestion, and myalgia 2, 5
• Tadalafil has lower rates of flushing compared to other PDE5 inhibitors 2
• Long-term studies show tadalafil is safe and well-tolerated for up to 24 months of treatment 5

Clinical Pearls

• Titrate doses to find the optimal balance between efficacy and side effects 2, 4
• Men with diabetes and post-prostatectomy patients have more severe ED at baseline and may respond less robustly to PDE5 inhibitors 2, 4
• For men with ED and testosterone deficiency, combining tadalafil with testosterone therapy may be more effective than tadalafil alone 2
• Tadalafil can work as quickly as 16-30 minutes after dosing, though individual response times vary 6