What is the recommended dose of Tadalafil (Cialis) for erectile dysfunction and pulmonary arterial hypertension?

Tadalafil Dosing Recommendations

Erectile Dysfunction

For erectile dysfunction, start with tadalafil 10 mg taken as needed prior to sexual activity, with dose adjustment to 20 mg for improved efficacy or 5 mg for tolerability, taken no more than once daily. 1

As-Needed Dosing (Preferred for Most Patients)

• Initial dose: 10 mg taken prior to anticipated sexual activity 1
• Dose titration: May increase to 20 mg or decrease to 5 mg based on individual response and tolerability 1
• Maximum frequency: Once per day 1
• Duration of effect: Effective up to 36 hours after dosing, allowing flexibility in timing of sexual activity 1, 2
• Onset of action: Erectogenic effect can occur as early as 16 minutes with the 20 mg dose and 26 minutes with the 10 mg dose 3

Once-Daily Dosing (Alternative for Spontaneous Activity)

• Initial dose: 2.5 mg taken at approximately the same time daily, without regard to timing of sexual activity 1
• Dose adjustment: May increase to 5 mg based on efficacy and tolerability 1
• Clinical evidence: Both 5 mg and 10 mg once-daily dosing significantly improved erectile function, with 84.5-84.6% of patients reporting improved erections compared to 28.3% with placebo 4
• Advantage: Provides an option for couples preferring spontaneous rather than scheduled sexual activity 5

Important Efficacy Note

• Unlike sildenafil, tadalafil does not demonstrate a clear dose-response relationship between 5 mg, 10 mg, and 20 mg 5
• Approximately 69% of men report improved erections with tadalafil versus 33% with placebo 5

Benign Prostatic Hyperplasia (BPH)

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

• Standard dose: 5 mg once daily 1
• Timing: Taken at approximately the same time every day 1
• Combination with finasteride: When initiating therapy for BPH with both tadalafil and finasteride, use tadalafil 5 mg once daily for up to 26 weeks 1
• Evidence: Improves International Prostate Symptom Score (IPSS) compared to placebo 5
• Important caveat: Do not combine low-dose daily 5 mg tadalafil with alpha blockers for BPH, as this offers no advantages in symptom improvement over either agent alone 5

Erectile Dysfunction and BPH Combined

For patients with both erectile dysfunction and BPH, use tadalafil 5 mg once daily without regard to timing of sexual activity. 1

Pulmonary Arterial Hypertension (PAH)

For PAH, the recommended dose is 40 mg once daily; treatment with more than 40 mg once daily has not been studied and is not recommended. 6

• WHO Functional Class II symptoms: Tadalafil is suggested to improve 6-minute walk distance (Grade 2B) 6
• WHO Functional Class III symptoms: Tadalafil is suggested to improve 6-minute walk distance, WHO functional class, delay time to clinical worsening, and improve cardiopulmonary hemodynamics (Grade 2B) 6
• Critical warning: Male patients treated with riociguat for PAH should be cautioned not to use PDE5 inhibitors like tadalafil for erectile dysfunction due to risk of systemic hypotension 6

Dose Adjustments for Special Populations

Renal Impairment (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

Renal Impairment (Once-Daily Dosing)

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

Hepatic Impairment

• Mild to moderate (Child-Pugh Class A or B): Maximum dose 10 mg once per day; use once-daily dosing with caution as it has not been extensively evaluated 1
• Severe (Child-Pugh Class C): Tadalafil is not recommended 1

Administration and Safety

• Food: May be taken without regard to food 1
• Tablet administration: Do not split tablets; entire dose should be taken 1
• Common adverse effects: Headache, dyspepsia, back pain, upper abdominal pain, and myalgia occur in at least 5% of patients 4
• Long-term safety: Tadalafil at doses of 5,10, or 20 mg taken as needed up to once daily for 18-24 months was safe and well tolerated, with discontinuation due to adverse events in only 6.3% of patients 7
• Serious adverse events: Occur in approximately 8.6% of patients, with no consistent pattern causally associated with tadalafil 7