What is the maximum recommended dose of Cialis (tadalafil) for a patient with a history of medical conditions such as heart disease, high blood pressure, or impaired renal function?

Maximum Dose of Cialis (Tadalafil)

The maximum dose of Cialis depends on the indication and dosing schedule: for as-needed use in erectile dysfunction, the maximum is 20 mg once daily; for once-daily dosing (ED, BPH, or both), the maximum is 5 mg daily. 1

Maximum Dosing by Indication

For Erectile Dysfunction (As-Needed Dosing)

• Maximum dose: 20 mg taken once per day 1
• Starting dose is typically 10 mg, which can be increased to 20 mg or decreased to 5 mg based on efficacy and tolerability 1
• Maximum dosing frequency is once per day 1
• Tadalafil improves erectile function for up to 36 hours after dosing, allowing flexibility in timing of sexual activity 1, 2

For Erectile Dysfunction (Once-Daily Dosing)

• Maximum dose: 5 mg taken once daily 1
• Starting dose is 2.5 mg daily, which may be increased to 5 mg based on response 1
• This regimen allows spontaneous sexual activity without timing medication around intercourse 3

For Benign Prostatic Hyperplasia (BPH)

• Maximum dose: 5 mg taken once daily 1
• No dose titration is recommended for BPH indication 1

For Combined ED and BPH

• Maximum dose: 5 mg taken once daily 1
• Same dosing as BPH alone 1

Critical Dose Reductions in Special Populations

Renal Impairment (As-Needed Dosing)

• Creatinine clearance 30-50 mL/min: Maximum 10 mg once every 48 hours (starting dose 5 mg once daily) 1
• Creatinine clearance <30 mL/min or hemodialysis: Maximum 5 mg once every 72 hours 1
• Once-daily dosing is not recommended in patients with creatinine clearance <30 mL/min due to increased drug exposure and inability to clear via dialysis 1

Renal Impairment (Once-Daily Dosing for BPH or ED/BPH)

• Creatinine clearance 30-50 mL/min: Start at 2.5 mg daily, may increase to maximum 5 mg daily 1
• Creatinine clearance <30 mL/min: Once-daily tadalafil is not recommended 1

Hepatic Impairment

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

Concomitant CYP3A4 Inhibitors

• When taking potent CYP3A4 inhibitors (ritonavir, ketoconazole, itraconazole): Maximum 10 mg once every 72 hours for as-needed dosing 1
• This restriction is necessary because tadalafil is metabolized predominantly by CYP3A4, and these inhibitors significantly increase drug exposure 1

Absolute Contraindications That Override Dosing

Nitrate Use

• Tadalafil is absolutely contraindicated with any nitrate use (nitroglycerin, isosorbide mononitrate, isosorbide dinitrate) due to risk of life-threatening hypotension 4, 1
• Both drugs work through the nitric oxide pathway, creating profound and potentially fatal vasodilation 4
• Patients must wait at least 48 hours after the last tadalafil dose before any nitrate can be safely administered, due to tadalafil's 17.5-hour half-life 4

Alpha-Blocker Considerations

• For ED: Patients should be stable on alpha-blocker therapy before starting tadalafil at the lowest dose 1
• For BPH: Combination of tadalafil and alpha-blockers is not recommended due to additive blood pressure lowering effects 1
• Patients on alpha-blockers for BPH should discontinue the alpha-blocker at least one day before starting tadalafil for once-daily BPH treatment 1

Common Pitfalls to Avoid

• Do not exceed 20 mg for as-needed dosing or 5 mg for once-daily dosing in any patient, regardless of perceived inadequate response 1
• Do not use once-daily dosing in severe renal impairment (CrCl <30 mL/min)—the drug accumulates and cannot be cleared by dialysis 1
• Do not prescribe standard doses in patients on CYP3A4 inhibitors—this can lead to excessive drug exposure and increased adverse effects 1
• Do not combine with nitrates under any circumstances—this is an absolute contraindication that can result in death 4, 1
• Do not split tablets—the entire dose should be taken as prescribed 1