Tadalafil Patient Counseling
Patients prescribed tadalafil must be counseled on absolute contraindications (especially nitrate use), proper timing and dosing, the requirement for sexual stimulation, common side effects, and critical warning signs requiring emergency care. 1, 2
Absolute Contraindications and Critical Safety
Nitrate medications are absolutely contraindicated with tadalafil due to potentially fatal hypotension; if nitrates are medically necessary after tadalafil use, at least 48 hours must elapse after the last tadalafil dose before nitrate administration. 1, 3, 2
Patients must be instructed to seek immediate medical attention if they experience anginal chest pain after taking tadalafil, as nitrate use may be life-threatening in this scenario. 2
Cardiovascular risk assessment is mandatory before prescribing; patients who cannot walk 1 mile in 20 minutes or climb 2 flights of stairs in 20 seconds without symptoms should be referred to cardiology before treatment. 1, 2
Proper Medication Administration
For as-needed dosing: Take one tablet at least 30 minutes before anticipated sexual activity; the ability to have sexual intercourse is improved for up to 36 hours. 2, 4
For once-daily dosing: Take one tablet at approximately the same time every day without regard for timing of sexual activity; erectile function improves over the course of continuous therapy. 2
Sexual stimulation is absolutely required for tadalafil to be effective—the medication does not cause automatic erections. 1, 2
Food and alcohol restrictions are not required, though substantial alcohol consumption (5 or more units) can increase risk of orthostatic symptoms including dizziness, headache, increased heart rate, and decreased blood pressure. 2
Defining Treatment Success and Failure
An adequate trial requires at least 5 separate occasions at maximum dose before declaring treatment failure, unless unacceptable side effects occur. 1, 5
Many perceived treatment failures are due to incorrect use—lack of sexual stimulation, inadequate dosing, or insufficient trial duration account for a large percentage of failures. 1, 5
If tadalafil fails after an adequate trial, switching to a different PDE5 inhibitor may be successful before proceeding to more invasive therapies. 1, 3
Common Side Effects
The most frequently reported adverse events include headache, dyspepsia, back pain, nasal congestion, myalgia, flushing, and dizziness; these typically follow a dose-response pattern. 1, 6
Most side effects are mild to moderate and transient. 6
Emergency Warning Signs
Seek emergency care immediately if erection lasts longer than 4 hours (whether painful or not), as priapism can result in irreversible damage to erectile tissue if not treated promptly. 2
Stop tadalafil and seek prompt medical attention for sudden vision loss in one or both eyes, which may indicate non-arteritic anterior ischemic optic neuropathy (NAION), a rare but serious condition that can cause permanent vision loss. 2
Stop tadalafil and seek prompt medical attention for sudden hearing loss or decrease, which may be accompanied by tinnitus and dizziness. 2
Special Populations and Drug Interactions
In patients with mild to moderate hepatic impairment, the dose should not exceed 10 mg for as-needed use; once-daily use requires caution. 2
In patients with severe hepatic or renal impairment, tadalafil use is not recommended. 1, 2
When taking potent CYP3A4 inhibitors (ritonavir, ketoconazole, itraconazole), limit as-needed tadalafil to 10 mg no more than once every 72 hours, or limit once-daily dosing to maximum 2.5 mg. 2
Alpha-blockers and antihypertensives may have additive blood pressure-lowering effects with tadalafil, particularly with once-daily dosing that provides continuous plasma levels. 2
Additional Counseling Points
Tadalafil offers no protection against sexually transmitted diseases, including HIV; discuss protective measures as appropriate. 2
Patients with testosterone deficiency should be informed that combining testosterone therapy with tadalafil may be more effective than tadalafil alone. 1
Lifestyle modifications including smoking cessation, weight loss, increased physical activity, and avoiding excess alcohol should be addressed alongside pharmacological treatment. 1, 3
Dose titration may be necessary to find the optimal balance between efficacy and minimizing side effects; work with patients to identify the most effective dose. 1, 5