What is the recommended dose and schedule for Tadalafil (Cialis)?

Recommended Dosage and Schedule for Tadalafil

The recommended dosage of tadalafil varies by indication: for erectile dysfunction (ED), start with 10 mg as needed before sexual activity (adjustable to 5-20 mg based on response) or 2.5-5 mg once daily; for benign prostatic hyperplasia (BPH), use 5 mg once daily; and for pulmonary hypertension, use 40 mg once daily. 1, 2

Dosing by Indication

Erectile Dysfunction (ED)

• As-needed dosing:

  • Starting dose: 10 mg taken prior to anticipated sexual activity 1
  • Dose range: May be increased to 20 mg or decreased to 5 mg based on individual efficacy and tolerability 1
  • Maximum frequency: Once per day 1
  • Effective window: Improves erectile function for up to 36 hours following dosing 1, 3

• Once-daily dosing:

  • Starting dose: 2.5 mg taken at approximately the same time every day 1
  • May be increased to 5 mg based on individual response 1
  • Allows for spontaneous rather than scheduled sexual activity 4, 5
  • Particularly beneficial for patients with incomplete response to as-needed therapy 6

Benign Prostatic Hyperplasia (BPH)

• 5 mg once daily, taken at approximately the same time every day 1, 7
• When initiated with finasteride, 5 mg once daily for up to 26 weeks 1

Combined ED and BPH

• 5 mg once daily, taken at approximately the same time every day 1, 8

Pulmonary Hypertension

• 40 mg once daily 7, 2
• Has shown favorable results on exercise capacity, symptoms, hemodynamics, and time to clinical worsening 7

Dosage Adjustments for Special Populations

Renal Impairment

• Moderate impairment (CrCl 30-50 mL/min):

  • As-needed: Start with 5 mg, maximum 10 mg every 48 hours 1, 2
  • Once-daily: Start with 2.5 mg, may increase to 5 mg based on response 1

• Severe impairment (CrCl <30 mL/min):

  • As-needed: Maximum 5 mg every 72 hours 1
  • Once-daily: Not recommended 1

Hepatic Impairment

• Mild to moderate impairment (Child-Pugh Class A or B):
  • Maximum 10 mg once per day 1
  • Once-daily dosing has not been extensively evaluated 1

Important Precautions

Drug Interactions

• Nitrates: Absolutely contraindicated due to risk of severe hypotension 7, 2

  • After taking sildenafil or vardenafil, avoid nitrates for ≥24 hours
  • After taking tadalafil, avoid nitrates for ≥48 hours (due to its longer half-life of 17.5 hours) 7

• Other PDE5 inhibitors: Do not combine with other PDE5 inhibitors 2

• Alpha blockers:

  • Combination of tadalafil with alpha blockers for BPH treatment offers no advantage in symptom improvement over either agent alone 7
  • Use caution due to potential for additive blood pressure-lowering effects

Administration Considerations

• May be taken without regard to food 1
• Do not split tablets; entire dose should be taken 1
• For optimal results with as-needed dosing, patients should be advised of the 36-hour window of effectiveness 3

Efficacy and Safety

• Once-daily tadalafil (5 mg or 10 mg) has been shown to be well tolerated and significantly improve erectile function in men with ED 4, 5
• Tadalafil 5 mg significantly improves both ED and BPH-related symptoms through 12 weeks of treatment 8
• Common side effects include headache, flushing, dyspepsia, nasal congestion, back pain, and myalgia, which are generally mild to moderate 2, 4

By following these dosing recommendations and considering patient-specific factors, tadalafil can be effectively and safely used for its approved indications.