Tadalafil (Cialis) for Erectile Dysfunction & Cardiovascular Health — Libido & Sex
Long-acting PDE5 inhibitor FDA-approved for ED and BPH, with emerging cardiovascular and endothelial benefits at daily low doses.
Overview
Tadalafil is a long-acting phosphodiesterase type 5 (PDE5) inhibitor with a half-life of approximately 17.5 hours — significantly longer than sildenafil (4-5 hours) or vardenafil (4-5 hours). This extended duration allows for daily dosing at 2.5-5 mg, providing continuous erectile readiness without timing to sexual activity. FDA-approved for both erectile dysfunction and benign prostatic hyperplasia (BPH), tadalafil inhibits PDE5-mediated degradation of cyclic GMP (cGMP), resulting in smooth muscle relaxation and increased blood flow in the corpus cavernosum, prostate, and bladder. Daily low-dose tadalafil (5 mg) has demonstrated additional benefits beyond sexual function, including improved endothelial function, reduced arterial stiffness, and potential cardioprotective effects. Studies in heart failure patients (CELADON trial) showed improved exercise capacity and quality of life. The drug also crosses the blood-brain barrier and has been investigated for Raynaud's phenomenon, pulmonary hypertension, and exercise performance. Tadalafil's selectivity for PDE5 over PDE6 (retinal) is higher than sildenafil, resulting in fewer visual side effects.
Indications
- FDA-approved: Erectile dysfunction (on-demand and daily dosing)
- FDA-approved: Benign prostatic hyperplasia (BPH) symptoms
- FDA-approved: Combined ED and BPH
- FDA-approved: Pulmonary arterial hypertension (Adcirca, 40 mg)
- Off-label: Endothelial function and cardiovascular health
- Off-label: Raynaud's phenomenon
- Off-label: Exercise performance enhancement
Mechanism of Action
Selectively inhibits phosphodiesterase type 5 enzyme, preventing degradation of cyclic GMP in corpus cavernosum smooth muscle
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Tadalafil | 5 mg | Once daily | Daily dosing for continuous effect; also approved for BPH |
| Tadalafil | 10 mg | As needed (prior to activity) | Starting on-demand dose; take 30-60 min before activity |
| Tadalafil | 20 mg | As needed | Maximum on-demand dose; effective up to 36 hours |
| Tadalafil | 2.5 mg | Once daily | Low daily dose for cardiovascular/endothelial benefits |
Evidence Grade
GRADE A
Safety & Contraindications
- Contraindicated with nitrate medications — risk of severe hypotension
- Contraindicated with riociguat (guanylate cyclase stimulator)
- Headache (15%), dyspepsia (10%), back pain/myalgia (5-6%) — unique to tadalafil
- Flushing and nasal congestion common
- Priapism (rare but emergency) — seek medical attention if erection >4 hours
- Caution with alpha-blockers — may cause orthostatic hypotension
- Hearing loss (rare, SNHL) — FDA black box consideration
- Avoid grapefruit juice (CYP3A4 inhibition increases levels)