Cialis Dosing for Erectile Dysfunction
For most patients with ED, start with tadalafil 10 mg taken as needed prior to sexual activity, with dose adjustment to 20 mg or 5 mg based on response and tolerability; alternatively, consider tadalafil 2.5-5 mg once daily for patients preferring spontaneous sexual activity without timing medication. 1
Critical Pre-Treatment Safety Assessment
Before prescribing tadalafil to any patient, especially those with cardiovascular disease history:
- Verify the patient is not taking nitrates in any form (oral, sublingual, transdermal, or recreational)—this is an absolute contraindication due to potentially fatal hypotension. 2, 1
- Assess cardiovascular fitness by asking if the patient can walk 1 mile in 20 minutes or climb 2 flights of stairs without symptoms—if unable, refer to cardiology before prescribing. 3, 2
- High-risk patients (unstable angina, uncontrolled hypertension, recent MI <2 weeks, NYHA Class II-IV heart failure, severe valvular disease) should defer ED treatment until cardiac condition is stabilized. 3
- Low-risk patients (controlled hypertension, mild stable angina, successful revascularization, uncomplicated past MI >2 weeks, NYHA Class I heart failure) can safely receive PDE5 inhibitors. 2
As-Needed Dosing Regimen
The FDA-approved starting dose is 10 mg taken prior to anticipated sexual activity, with a maximum frequency of once per day. 1
- Increase to 20 mg if 10 mg provides inadequate response. 1
- Decrease to 5 mg if adverse effects are intolerable. 1
- Tadalafil remains effective for up to 36 hours after dosing, allowing flexibility in timing of sexual activity. 1, 4
- Sexual stimulation is required for effectiveness—this is a common cause of apparent treatment failure. 2
Important Nuance on Dose-Response
Unlike sildenafil and vardenafil, tadalafil does NOT show dose-dependent improvement in erectile function between 5 mg, 10 mg, and 20 mg doses. 2 This means the choice between 10 mg and 20 mg should be based primarily on tolerability rather than expecting dramatically better efficacy at higher doses. 2
Once-Daily Dosing Alternative
For patients who prefer spontaneous sexual activity without timing medication, start tadalafil 2.5 mg once daily, with potential increase to 5 mg based on response. 1
- Take at approximately the same time every day, without regard to timing of sexual activity. 1
- This eliminates the need to plan sexual activity around medication timing. 2, 5
- Once-daily tadalafil 5 mg has been shown to be well-tolerated and effective in long-term studies up to 24 months. 6, 7
Defining an Adequate Trial Before Declaring Failure
An adequate trial requires at least 5 separate attempts at the maximum tolerated dose before concluding tadalafil is ineffective. 2
Before switching therapies, systematically evaluate these modifiable factors:
- Inadequate sexual stimulation (required for PDE5 inhibitors to work). 2
- Improper timing of dose or food interactions. 2
- Heavy alcohol use (impairs erectile function and increases adverse effects). 2
- Undiagnosed testosterone deficiency (<300 ng/dL). 2
- Relationship issues with partner. 2
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
Hepatic Impairment
- Mild-moderate (Child-Pugh A or B): Maximum 10 mg once per day. 1
- Severe (Child-Pugh C): Tadalafil is not recommended. 1
Cardiovascular Safety Considerations
The Princeton III Consensus confirms that PDE5 inhibitors including tadalafil are safe when used correctly, with no new cardiovascular safety concerns in postmarketing surveillance. 3 In fact, studies demonstrate potential benefits for PDE5 inhibition in managing hypertension and endothelial dysfunction in patients at risk for CVD. 3
Emergency Nitrate Protocol
If a patient on tadalafil requires emergency nitrate administration, wait 48 hours after the last tadalafil dose before giving nitrates, under close medical supervision with continuous monitoring. 2 (Note: This is 48 hours for tadalafil vs. 24 hours for sildenafil due to tadalafil's longer half-life.)
Combination Therapy Considerations
For men with both ED and testosterone deficiency (<300 ng/dL), combining tadalafil with testosterone replacement therapy is more effective than tadalafil alone. 2 Check total testosterone, free testosterone, and SHBG levels before declaring treatment failure. 2
For patients with both ED and BPH, tadalafil 5 mg once daily is FDA-approved to treat both conditions simultaneously. 2, 1
Common Adverse Effects
The most frequent side effects include:
Tadalafil has lower rates of flushing and visual disturbances compared to sildenafil. 2, 8
Ongoing Management
Periodic follow-up should assess: