What is the recommended dosage and treatment plan for Tadalafil (tadalafil) in patients with erectile dysfunction (ED) or benign prostatic hyperplasia (BPH)?

Tadalafil Dosing and Treatment Plan

Erectile Dysfunction

For erectile dysfunction, start with tadalafil 10 mg taken as needed prior to sexual activity, with dose adjustment to 20 mg or 5 mg based on response and tolerability, or alternatively use 2.5-5 mg once daily for patients preferring spontaneous sexual activity. 1

As-Needed Dosing (Preferred for Most Patients)

• Starting dose: 10 mg taken prior to anticipated sexual activity 1
• Titrate to 20 mg if inadequate response or decrease to 5 mg if side effects occur 1
• Maximum dosing frequency: once per day 1
• Tadalafil remains effective up to 36 hours after dosing, allowing flexibility in timing 1
• Critical: Tadalafil does NOT show dose-dependent improvement between 5 mg, 10 mg, and 20 mg—choose between 10 mg and 20 mg based primarily on tolerability rather than expecting dramatically better efficacy at higher doses 2, 3

Once-Daily Dosing (For Spontaneous Sexual Activity)

• Starting dose: 2.5 mg taken at approximately the same time every day 1
• May increase to 5 mg based on efficacy and tolerability 1
• Eliminates need to time medication with sexual activity, providing an alternative for couples who prefer spontaneous rather than scheduled intimacy 2, 3
• Once-daily dosing produces the same level of efficacy as on-demand dosing 4

Critical Instructions to Maximize Efficacy

• Sexual stimulation is necessary for tadalafil to be effective—incorrect use (lack of sexual stimulation, medication taken with large meal) accounts for many treatment failures 2, 5
• An adequate trial consists of at least 5 separate attempts at maximum dose before declaring treatment failure 2
• May be taken without regard to food 1
• Do not split tablets; entire dose should be taken 1

Benign Prostatic Hyperplasia (BPH)

For BPH treatment, use tadalafil 5 mg once daily taken at approximately the same time every day. 1

• Recommended dose: 5 mg once daily 1, 3
• Significantly improves International Prostate Symptom Score (IPSS) compared to placebo 3, 6, 7
• When initiating therapy for BPH with both tadalafil and finasteride, use tadalafil 5 mg once daily for up to 26 weeks 1
• Tadalafil 5 mg daily should be discussed as a treatment option for patients with LUTS/BPH regardless of comorbid erectile dysfunction 3

Combined ED and BPH

For patients with both erectile dysfunction and BPH, use tadalafil 5 mg once daily, which treats both conditions simultaneously. 1

• Single dose of 5 mg once daily is FDA-approved for treating both conditions 2, 1
• Taken at approximately the same time every day, without regard to timing of sexual activity 1
• Significantly improves both IIEF-EF domain scores and IPSS 6
• Do NOT combine tadalafil 5 mg daily with alpha-blockers—this offers no advantages in symptom improvement over either agent alone 3

Renal Impairment Adjustments

As-Needed Dosing

• CrCl 30-50 mL/min: Start with 5 mg, maximum 10 mg once every 48 hours 1
• CrCl <30 mL/min or hemodialysis: Maximum 5 mg once every 72 hours 1

Once-Daily Dosing

• CrCl 30-50 mL/min (for BPH or ED/BPH): Start with 2.5 mg, may increase to 5 mg based on response 1
• CrCl <30 mL/min or hemodialysis: Once-daily dosing NOT recommended 1

Hepatic Impairment Adjustments

• Mild or moderate (Child-Pugh Class A or B): Maximum 10 mg once per day for as-needed dosing; use caution with once-daily dosing 1
• Severe (Child-Pugh Class C): Tadalafil NOT recommended 1

Absolute Contraindications and Critical Safety

Tadalafil is absolutely contraindicated in patients taking oral nitrates due to risk of dangerous, potentially fatal hypotension. 2

• Patients must be explicitly asked about ALL forms of nitrate use before prescribing 2
• If emergency nitrate administration is required: wait 48 hours after tadalafil before giving nitrates, under close medical supervision 2
• When coadministering with alpha-blockers for ED, patients should be stable on alpha-blocker therapy prior to initiating tadalafil, and start at the lowest recommended dose 1

Cardiovascular Risk Assessment

• Assess cardiovascular risk before prescribing, including evaluating the patient's ability to perform moderate physical activity 2
• Patients whose cardiovascular risk is indeterminate or who cannot perform moderate physical activity should be referred to cardiology before prescribing 2
• Most ED patients fall into low-risk category and can safely receive tadalafil, including those with asymptomatic CAD with <3 risk factors, controlled hypertension, mild stable angina, successful coronary revascularization, uncomplicated past MI, mild valvular disease, and CHF (NYHA class I) 2
• The diagnosis of ED provides a pivotal opportunity to discuss cardiovascular risk—communicate this increased risk to the patient, partner, and primary care provider 4

Special Populations

• Men with diabetes and post-prostatectomy patients have more severe ED at baseline and respond less robustly to PDE5 inhibitors 4, 2
• 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 effective monotherapy for ED 2

Common Adverse Events

• Most common: dyspepsia, headache, back pain, nasal congestion, myalgia 4, 3
• Tadalafil has lower rates of flushing compared to other PDE5 inhibitors 2
• Most adverse events are mild to moderate in intensity 8, 9

Follow-Up and Treatment Failure Evaluation

• Periodic follow-up should assess efficacy, side effects, and any significant changes in health status or medications 2
• Before declaring treatment failure or switching therapies, evaluate whether the trial was adequate by addressing: hormonal abnormalities, food or drug interactions, timing and frequency of dosing, adequacy of sexual stimulation, heavy alcohol use, and relationship issues 2
• Consider switching to a different PDE5 inhibitor if first one fails after adequate trial 2