Generic name: Tadalafil

Brand names: Cialis®, Adcirca®

Tadalafil is a prescription medication that belongs to the class of phosphodiesterase type 5 (PDE5) inhibitors. It is primarily used to treat:

• Erectile Dysfunction (ED)
• Benign Prostatic Hyperplasia (BPH)
• Pulmonary Arterial Hypertension (PAH)

By blocking PDE5, tadalafil relaxes smooth muscle and improves blood flow, particularly in the pelvic region.

How to Take

• Take exactly as prescribed by your provider.
• For ED, it may be taken once daily at a lower dose or as needed at least 30 minutes before activity.
• For BPH or PAH, it is usually prescribed as a daily dose.
• Do not exceed one dose per day.
• May be taken with or without food.
• Limit alcohol intake to avoid excessive blood pressure drop.

Role in Testosterone Replacement Therapy (TRT)

• Adjunct in TRT: Tadalafil is often used alongside testosterone therapy to improve erectile function, libido, and urinary symptoms.
• Synergistic Benefits: Studies support that daily low-dose tadalafil (5 mg) combined with TRT can enhance sexual function and quality of life more than either therapy alone.
• Hormonal Modulation: Some evidence suggests that tadalafil may reduce estradiol levels by mildly influencing aromatase activity (the enzyme that converts testosterone to estrogen). While not a direct aromatase inhibitor, this effect may support a more favorable testosterone-to-estrogen balance in some men on TRT.
• Prostate Health: By relaxing smooth muscle in the bladder and prostate, tadalafil may reduce urinary symptoms commonly associated with low testosterone and BPH.

(Note: These uses are considered supportive and are prescribed at the discretion of a qualified provider.)

Possible Side Effects

Common:

• Headache
• Flushing or facial warmth
• Indigestion
• Muscle or back pain
• Nasal congestion

Serious (seek immediate medical care):

• Sudden vision or hearing loss
• Chest pain, irregular heartbeat
• Severe dizziness or fainting
• Erection lasting longer than 4 hours (priapism – emergency)

Contraindications

Do not take tadalafil if:

• You use nitrates (e.g., nitroglycerin) or riociguat (dangerous blood pressure drop).
• You have severe heart disease, unstable angina, or recent heart attack/stroke.
• You have severe liver impairment.
• You are allergic to tadalafil.

Drug Interactions

• Nitrates – contraindicated (life-threatening hypotension).
• Alpha-blockers / antihypertensives – may increase risk of low blood pressure.
• CYP3A4 inhibitors (ritonavir, ketoconazole, clarithromycin) – increase tadalafil levels.
• CYP3A4 inducers (rifampin, carbamazepine, phenytoin) – reduce tadalafil effectiveness.
• Alcohol – additive dizziness and hypotension.
• Other ED medications – should not be combined.

General Precautions

• Inform your provider if you have cardiovascular disease, low blood pressure, vision disorders, priapism history, liver/kidney impairment, or active prostate cancer.
• Avoid grapefruit juice, which may interfere with tadalafil metabolism.
• Not recommended in individuals under 18 years of age.
• Store at room temperature, away from light and moisture.

References:

• Porst H, Kim ED, Casabé AR, et al. Efficacy and safety of tadalafil once daily in men with erectile dysfunction: integrated analysis of clinical trial data. J Urol. 2014.
• Spitzer M, Basaria S, Travison TG, et al. Effect of testosterone replacement and tadalafil on erectile function and quality of life in men with ED and hypogonadism. J Clin Endocrinol Metab. 2013.
• FDA Prescribing Information: Tadalafil (Cialis®, Adcirca®).
• Mayo Clinic. “Tadalafil (Oral Route): Uses and Safety.”

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