What is the recommended treatment for erectile dysfunction using Cialis (tadalafil)?

Tadalafil for Erectile Dysfunction

Tadalafil is the recommended first-line oral therapy for erectile dysfunction, with a starting dose of 10 mg taken as needed prior to sexual activity, which can be titrated to 20 mg or reduced to 5 mg based on response and tolerability. 1, 2

Dosing Strategies

As-Needed Dosing

• Start with 10 mg taken prior to anticipated sexual activity as the standard initial dose 2
• Titrate to 20 mg if response is inadequate or reduce to 5 mg if side effects occur 2
• Maximum dosing frequency is once per day 2
• Tadalafil remains effective for up to 36 hours after dosing, providing a prolonged therapeutic window compared to other PDE5 inhibitors 2, 3
• Do not split tablets—the entire dose must be taken 2

Once-Daily Dosing

• Start with 2.5 mg daily taken at approximately the same time each day, without regard to timing of sexual activity 2
• Can increase to 5 mg daily based on efficacy and tolerability 2
• This regimen eliminates the need to time medication with sexual activity, providing spontaneity for couples who prefer unscheduled intimacy 1
• Once-daily dosing may restore normal erectile function (IIEF-EF score ≥26) in 39-40% of men who had incomplete responses to as-needed PDE5 inhibitor therapy 4

Efficacy

• 69% of men using tadalafil as needed report successful sexual intercourse attempts compared to 33% with placebo 1
• Tadalafil 20 mg produces a mean improvement of 7.9 points in IIEF erectile function domain score from baseline (p<0.001 vs placebo) 5
• 75% of intercourse attempts are successfully completed with tadalafil 20 mg versus placebo 5
• Efficacy is NOT dose-dependent between 5 mg, 10 mg, and 20 mg—unlike sildenafil and vardenafil, higher doses of tadalafil do not necessarily provide greater efficacy, so dose selection should be based primarily on tolerability 1

Critical Safety Requirements

Absolute Contraindication

• Never prescribe tadalafil to patients taking oral nitrates—this combination causes potentially fatal hypotension 1, 6
• Wait 48 hours after tadalafil before administering emergency nitrates (compared to 24 hours for sildenafil) 6

Cardiovascular Risk Stratification

• Assess cardiovascular risk before prescribing using the Princeton Consensus Panel criteria 6
• Low-risk patients can safely receive tadalafil, including those with asymptomatic coronary artery disease with <3 risk factors, controlled hypertension, mild stable angina, successful coronary revascularization, uncomplicated past MI, mild valvular disease, and CHF (NYHA class I) 6
• Refer to cardiology before prescribing if cardiovascular risk is indeterminate or if the patient cannot perform moderate physical activity 1, 6
• High-risk patients should not receive ED treatment until stabilized, including those with unstable or refractory angina, uncontrolled hypertension, left ventricular dysfunction/CHF (NYHA class II or greater), MI or stroke within previous 2 weeks, high-risk arrhythmias, hypertrophic obstructive cardiomyopathies, and moderate-to-severe valvular disease 6

Common Adverse Events

• Dyspepsia, headache, back pain, nasal congestion, and myalgia are the most common side effects 1
• Tadalafil has lower rates of flushing compared to other PDE5 inhibitors 1, 6
• Adverse events are generally mild to moderate and well-tolerated 6, 5

Ensuring Adequate Trial Before Declaring Failure

• Require at least 5 separate attempts at maximum dose before considering tadalafil ineffective 1, 6
• Sexual stimulation is necessary for tadalafil to be effective—incorrect use accounts for a large percentage of treatment failures 1
• Before switching therapies, evaluate: hormonal abnormalities, food or drug interactions, timing and frequency of dosing, adequacy of sexual stimulation, heavy alcohol use, and relationship issues with partner 6

Special Populations

Diabetes and Post-Prostatectomy

• Men with diabetes and post-prostatectomy patients have more severe ED at baseline and may respond less robustly to PDE5 inhibitors 1
• However, tadalafil remains effective in these populations 1, 7

Testosterone Deficiency

• For men with ED and testosterone deficiency, combining tadalafil with testosterone therapy may be more effective than tadalafil alone 1
• Testosterone therapy alone is not effective monotherapy for ED 1
• Check total testosterone, free testosterone, and SHBG levels if patients present with decreased libido, premature ejaculation, fatigue, testicular atrophy, or muscle atrophy 1, 6

Renal Impairment (As-Needed Dosing)

• Creatinine clearance 30-50 mL/min: Start with 5 mg, maximum 10 mg once every 48 hours 2
• Creatinine clearance <30 mL/min or hemodialysis: Maximum 5 mg once every 72 hours 2

Renal Impairment (Once-Daily Dosing)

• Creatinine clearance <30 mL/min or hemodialysis: Once-daily tadalafil is not recommended 2

Hepatic Impairment

• Mild or moderate (Child-Pugh Class A or B): Maximum dose 10 mg once per day; use once-daily dosing with caution 2
• Severe (Child-Pugh Class C): Tadalafil is not recommended 2

Administration

• May be taken without regard to food 2
• Alcohol intake is not restricted, though excessive alcohol should be avoided 6, 5

Combination Therapy for BPH and ED

• Tadalafil 5 mg daily is FDA-approved to treat both BPH and ED simultaneously 1, 2
• When initiating BPH treatment with tadalafil and finasteride, use tadalafil 5 mg daily for up to 26 weeks 2

Advantages Over Other PDE5 Inhibitors

• 17.5-hour half-life provides a 36-hour window of opportunity, ideal for men who prefer spontaneity 6, 3
• Lower flushing rates compared to sildenafil and vardenafil 1, 6
• Once-daily dosing option eliminates need to time medication with sexual activity 1