Cialis (Tadalafil) Titration Strategy
For erectile dysfunction, start tadalafil at 10 mg taken as needed (up to 36 hours before sexual activity), then titrate to 20 mg if inadequate response or down to 5 mg if side effects occur; alternatively, use 2.5 mg daily with option to increase to 5 mg daily based on efficacy and tolerability. 1
As-Needed Dosing for Erectile Dysfunction
Starting dose: 10 mg taken prior to anticipated sexual activity 1
Titration approach:
- Increase to 20 mg if additional efficacy needed 1
- Decrease to 5 mg if tolerability issues arise 1
- Maximum frequency: once per day 1
- Effective window: up to 36 hours after dosing 1
Key clinical principle: The clinician should work with the patient to find the dose that meets treatment expectations without unacceptable adverse effects, which may require titrating initial doses up or down until optimal dosing is identified 2. Importantly, improvement in erectile function with tadalafil is NOT dose-related, unlike sildenafil and vardenafil where higher doses show superior outcomes 3.
Daily Dosing for Erectile Dysfunction
Starting dose: 2.5 mg once daily at approximately the same time each day 1
Titration approach:
- Increase to 5 mg once daily based on individual efficacy and tolerability 1
- Timing is independent of sexual activity 1
Daily tadalafil 5 mg and 10 mg both significantly improved erectile function with similar efficacy (IIEF EF domain improvements of 9.7 and 9.4 respectively), and both were well tolerated 4.
Special Population Dosing Adjustments
Renal impairment (as-needed dosing):
- CrCl 30-50 mL/min: Start 5 mg, maximum 10 mg once every 48 hours 1
- CrCl <30 mL/min or hemodialysis: Maximum 5 mg once every 72 hours 1
Renal impairment (daily dosing for ED):
- CrCl <30 mL/min or hemodialysis: Not recommended 1
Hepatic impairment:
- Mild/moderate (Child-Pugh A or B): Maximum 10 mg once daily for as-needed dosing; use caution with daily dosing 1
- Severe (Child-Pugh C): Not recommended 1
Critical Safety Considerations
Absolute contraindication: Nitrates in any form are contraindicated with tadalafil 1. Patients must avoid nitrates for at least 48 hours after tadalafil use due to severe hypotension risk 3.
Alpha-blocker coadministration: Patients should be stable on alpha-blocker therapy before initiating tadalafil, and tadalafil should start at the lowest recommended dose 1.
Cardiovascular assessment: Assess cardiovascular risk before prescribing, particularly in patients unable to perform moderate exercise 3.
Common Adverse Effects
The most frequent adverse events include:
- Headache (15.8% in long-term studies) 5
- Dyspepsia (11.8%) 5
- Back pain (8.2%) 5
- Flushing 2
- Nasal congestion 2
- Myalgia 2
Most adverse events are transient and mild to moderate in severity 2. Long-term studies (18-24 months) showed only 6.3% discontinuation rate due to adverse events 5.
Patient Education Pitfalls
Critical counseling points to avoid treatment failure:
- Sexual stimulation is necessary for tadalafil to work 2
- More than one trial may be required to establish efficacy 2
- For as-needed dosing, avoid taking with large meals (though food does not affect absorption, it may delay onset) 1
- Do not split tablets; take entire dose 1
Incorrect use (lack of sexual stimulation, medication taken with large meal) accounts for a large percentage of treatment failures 2.
Efficacy in Special Populations
Diabetes: Tadalafil significantly improved erectile function in men with diabetes, with efficacy independent of baseline HbA1c levels 6. However, men with diabetes have more severe ED at baseline and respond less robustly to PDE5 inhibitors compared to the general ED population 2.
Testosterone deficiency: Tadalafil combined with testosterone therapy is more effective than tadalafil alone in men with both ED and testosterone deficiency 2.