What are the considerations and guidelines for prescribing Cialis (tadalafil) to a patient with erectile dysfunction (ED) or benign prostatic hyperplasia (BPH)?

Prescribing Cialis (Tadalafil) for Erectile Dysfunction and Benign Prostatic Hyperplasia

Tadalafil is a first-line FDA-approved PDE5 inhibitor for treating erectile dysfunction (ED), benign prostatic hyperplasia (BPH), or both conditions simultaneously, with proven efficacy showing 69% success rates for ED and modest but significant improvements in urinary symptoms for BPH. 1, 2

Critical Safety Screening Before Prescribing

Absolute contraindication: Verify the patient is not taking nitrates in any form (oral, sublingual, transdermal, or recreational) before prescribing, as the combination can cause potentially fatal hypotension. 3, 2

Cardiovascular Risk Stratification

Assess cardiovascular fitness by asking if the patient can:

• Walk 1 mile in 20 minutes, OR
• Climb 2 flights of stairs without symptoms 3

Low-risk patients (safe to prescribe):

• Asymptomatic coronary artery disease with <3 risk factors
• Controlled hypertension
• Mild, stable angina
• Successful coronary revascularization
• Uncomplicated past MI
• Mild valvular disease
• CHF (NYHA class I) 3

High-risk patients (defer treatment):

• Unstable angina
• Uncontrolled hypertension
• Recent MI
• NYHA Class II-IV heart failure
• Severe valvular disease 3

Indeterminate risk: Refer to cardiology before prescribing if the patient cannot perform moderate physical activity. 3

Dosing Regimens

For Erectile Dysfunction Alone

As-needed dosing (preferred for scheduled sexual activity):

• Starting dose: 10 mg taken at least 30 minutes before sexual activity 2
• Effective for up to 36 hours 3
• Titrate to 20 mg or down to 5 mg based on tolerability, NOT efficacy—tadalafil does NOT show dose-dependent improvement between 5-20 mg 3
• Maximum frequency: Once per 24 hours 2

Daily dosing (preferred for spontaneous sexual activity):

• 2.5-5 mg once daily at approximately the same time each day 3, 2
• Eliminates need to time medication with sexual activity 3
• Provides continuous readiness for sexual activity 2

For BPH Alone

Daily dosing only:

• 5 mg once daily 4, 2, 5
• Mean IPSS improvement: -5.4 points vs -3.6 with placebo (difference of -1.74 points) 4
• Do NOT combine with alpha-blockers—offers no additional benefit and increases side effect risk 4, 6, 2
• If patient is on an alpha-blocker, discontinue it at least one day before starting tadalafil 2

For Combined ED/BPH

Daily dosing:

• 5 mg once daily treats both conditions simultaneously 3, 2, 5
• This is the most appropriate indication for tadalafil in BPH, as it addresses both conditions 6

Special Populations and Dose Adjustments

Renal Impairment

As-needed dosing:

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

Daily dosing:

• CrCl 30-50 mL/min: Start 2.5 mg daily, may increase to 5 mg based on response 2
• CrCl <30 mL/min: NOT recommended 2

Hepatic Impairment

As-needed dosing:

• Mild to moderate: Maximum 10 mg 2
• Severe: NOT recommended 1, 2

Daily dosing:

• Use with caution in mild to moderate impairment 2
• Severe: NOT recommended 2

Diabetes and Post-Prostatectomy

These patients have more severe ED at baseline and respond less robustly to PDE5 inhibitors, but tadalafil remains effective. 1, 3

Optimizing Treatment Success

Defining an Adequate Trial

Before declaring treatment failure, ensure:

• At least 5 separate attempts at maximum tolerated dose 3
• Adequate sexual stimulation (tadalafil requires sexual arousal to work) 3
• Proper timing (at least 30 minutes before activity for as-needed dosing) 3, 2
• Avoid heavy alcohol use (>5 units) 3, 2
• Address relationship issues with partner 3
• Evaluate and correct hormonal abnormalities (check testosterone if response is suboptimal) 3

Combination with Testosterone

For men with ED and confirmed testosterone deficiency, combining tadalafil with testosterone therapy is more effective than tadalafil alone. 3 However, testosterone alone is NOT effective monotherapy for ED. 3

Common Adverse Effects

Most frequent (dose-related):

• Headache
• Dyspepsia (lowest with avanafil among PDE5 inhibitors)
• Flushing (lowest with tadalafil among PDE5 inhibitors)
• Back pain
• Nasal congestion
• Myalgia 1, 3, 2

Serious but rare:

• Priapism (erection >4 hours requires emergency care) 2
• Sudden vision loss (NAION—stop medication immediately) 2
• Sudden hearing loss (stop medication immediately) 2

Critical Drug Interactions

Nitrates (Absolute Contraindication)

Emergency protocol if patient on tadalafil requires nitrates:

• Wait 48 hours after last tadalafil dose before administering nitrates 3
• Provide close medical supervision with continuous monitoring 3

Alpha-Blockers

For ED patients on alpha-blockers:

• Patient must be stable on alpha-blocker therapy first 2
• Start tadalafil at lowest dose (2.5 mg daily or 5 mg as-needed) 2
• Monitor for symptomatic hypotension 2

For BPH patients on alpha-blockers:

• Discontinue alpha-blocker at least one day before starting tadalafil 5 mg daily 2
• Do NOT use both together for BPH treatment 4, 2

Alcohol

Substantial alcohol consumption (≥5 units) combined with tadalafil increases risk of orthostatic hypotension, dizziness, and headache. 2

Cardiovascular Considerations

Important context: ED is as strong a predictor of future cardiac events as cigarette smoking or family history of MI. 1 The diagnosis of ED provides an opportunity to discuss cardiovascular risk with the patient, partner, and primary care provider. 1

Postmarketing surveillance confirms no new cardiovascular safety concerns with proper use, and tadalafil may have potential benefits for managing hypertension and endothelial dysfunction. 3

Limitation of Use with Finasteride

If initiating BPH treatment with tadalafil plus finasteride, this combination is recommended for up to 26 weeks only, as the incremental benefit of tadalafil decreases from 4 to 26 weeks, and benefit beyond 26 weeks is unknown. 2

Ongoing Management

Periodic follow-up should assess:

• Treatment effectiveness and patient satisfaction 3
• Side effects and tolerability 3
• Cardiovascular health changes 3
• New medications (especially nitrates, alpha-blockers, antihypertensives) 3
• Continued appropriateness of current regimen 3