What is the proper dosage and administration of Cialis (tadalafil) for erectile dysfunction or benign prostatic hyperplasia?

Proper Dosage and Administration of Cialis (Tadalafil) for Erectile Dysfunction and Benign Prostatic Hyperplasia

For erectile dysfunction, tadalafil should be started at 10 mg as needed before sexual activity, with possible adjustment to 5-20 mg based on efficacy and tolerability, or at 5 mg once daily; for benign prostatic hyperplasia, 5 mg once daily is the recommended dose regardless of erectile dysfunction status. 1, 2

Dosing for Erectile Dysfunction (ED)

As-Needed Dosing

• Starting dose: 10 mg taken prior to anticipated sexual activity 1
• Dose adjustment: May be increased to 20 mg or decreased to 5 mg based on individual efficacy and tolerability 1
• Maximum frequency: Once per day in most patients 1
• Timing: Can improve erectile function for up to 36 hours following dosing 1
• Administration: Take without regard to food; do not split tablets 1

Once-Daily Dosing for ED

• Starting dose: 2.5 mg taken at approximately the same time every day 1
• Dose adjustment: May be increased to 5 mg based on individual efficacy and tolerability 1
• Administration: Take without regard to timing of sexual activity 1

Dosing for Benign Prostatic Hyperplasia (BPH)

• Recommended dose: 5 mg once daily, taken at approximately the same time every day 1, 2
• Efficacy: Tadalafil 5 mg has been shown to improve IPSS (International Prostate Symptom Score) compared to placebo 2, 3
• Duration: Improvements in IPSS maintained with continued treatment over a 1-year period 3

Dosing for Combined ED and BPH

• Recommended dose: 5 mg once daily, taken at approximately the same time every day 1, 4
• Efficacy: Significantly improves both IPSS and IIEF-EF (International Index of Erectile Function-Erectile Function) scores 4

Special Population Considerations

Renal Impairment

• Moderate impairment (CrCl 30-50 mL/min):
  • For as-needed use: Start with 5 mg, maximum 10 mg every 48 hours 1
  • For once-daily use for BPH: Start with 2.5 mg, may increase to 5 mg based on response 1
• Severe impairment (CrCl <30 mL/min) or hemodialysis:
  • For as-needed use: Maximum 5 mg every 72 hours 1
  • For once-daily use: Not recommended 1

Hepatic Impairment

• Mild to moderate impairment (Child-Pugh Class A or B):
  • For as-needed use: Should not exceed 10 mg once per day 1
  • For once-daily use: Use with caution 1
• Severe impairment (Child-Pugh Class C): Not recommended 1

Drug Interactions

Nitrates

• Contraindicated: Do not use tadalafil with nitrates in any form due to risk of severe hypotension 1

Alpha-Blockers

• For ED: Patients should be stable on alpha-blocker therapy before starting tadalafil; start at lowest recommended dose 1
• For BPH: Tadalafil is not recommended in combination with alpha-blockers for BPH treatment 1, 2
• Important note: Clinicians should not offer the combination of low-dose daily 5mg tadalafil with alpha blockers for LUTS/BPH as it offers no advantages in symptom improvement over either agent alone 2

CYP3A4 Inhibitors

• For as-needed use: Maximum 10 mg, not to exceed once every 72 hours 1
• For once-daily use: Maximum 2.5 mg 1

Common Side Effects

The most frequently reported adverse events with tadalafil are:

• Dyspepsia
• Headache
• Flushing
• Back pain
• Nasal congestion
• Myalgia
• Visual disturbance
• Dizziness 2

Clinical Pearls

• Tadalafil is effective for both ED and BPH-related lower urinary tract symptoms, making it particularly valuable for men with both conditions 4
• Sexual stimulation is necessary for tadalafil to be effective for ED 2
• More than one trial with the medication may be required to establish efficacy 2
• In men with testosterone deficiency who are considering ED treatment with tadalafil, combination with testosterone therapy may be more effective than tadalafil alone 2
• Tadalafil is a reasonable option to trial in selected men with LUTS/BPH, ideally those with concomitant erectile dysfunction 2