Tadalafil
Long half-life (17.5 h) PDE5 inhibitor. FDA-approved for erectile dysfunction (Cialis), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (Adcirca).
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WHAT IS TADALAFIL?
Detailed overview
Tadalafil is a selective PDE5 inhibitor developed by Lilly (Cialis, FDA 2003). By selectively inhibiting phosphodiesterase-5, intracellular cGMP rises in smooth muscle (corpus cavernosum, prostate, lung arterioles), producing vasodilation and relaxation. The key difference from sildenafil (Viagra, 4 h half-life) vs tadalafil (17.5 h) is long duration: "weekender pill" nickname. Daily 2.5 and 5 mg dosing has been licensed since 2008, enabling an "always ready" use mode. BPH indication received FDA approval in 2011 at 5 mg daily: improvement in bladder function similar to alpha-blockers (IPSS score reduction). Adcirca (40 mg/day) for pulmonary arterial hypertension since 2009 (Galiè 2009 NEJM).
ATC code
G04BE08
Prescription
Prescription only (Rx)
Mechanism
Selective PDE5 enzyme inhibition, cGMP elevation
Half-life
17.5 h (longest among PDE5i)
Onset
30-45 min (PRN), 5-7 days (daily steady-state)
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 8
- Headache (most common, roughly 10-15%), often accompanying the vasodilatory effect.
- Facial flushing (5-10%) and nasal congestion due to vasodilation.
- Back pain and myalgia (3-8%), tadalafil-specific, likely from PDE11 cross-reactivity; usually mild and transient.
- Dyspepsia (indigestion, 4-10%) and dizziness.
- Symptomatic (orthostatic) hypotension, with increased risk when combined with alpha-blockers or other antihypertensives.
- Priapism: a painful erection lasting over 4 hours. Rare (<0.1%) but a medical EMERGENCY, risking permanent tissue damage and loss of potency; seek immediate urological care.
- NAION (non-arteritic ischemic optic neuropathy): sudden, often one-sided vision loss; stop immediately and seek ophthalmologic evaluation.
- Sudden hearing decrease or loss (rare), sometimes with tinnitus/dizziness; stop immediately and consult an ENT specialist.
Contraindications · 5
- Concomitant nitrate use (absolute, severe hypotension risk)
- Severe hypotension (SBP < 90), severe hypertension (SBP > 170, DBP > 100)
- Recent (< 90 d) MI, unstable angina, NYHA III-IV heart failure
- Stroke or life-threatening arrhythmia within 6 months
- Severe hepatic or renal impairment
Related Pharmaceuticals
Same therapeutic category
Studies
Related research and clinical findings
Efficacy and safety of tadalafil for the treatment of erectile dysfunction: results of integrated analyses
Brock GB, McMahon CG, Chen KK et al.
Update on the Safety of Phosphodiesterase Type 5 Inhibitors for the Treatment of Erectile Dysfunction.
Yafi FA, Sharlip ID, Becher EF
An update on new oral PDE5 inhibitors for the treatment of erectile dysfunction.
Palit V, Eardley I
Tadalafil for treatment of pulmonary arterial hypertension (PHIRST)
Galiè N, Brundage BH, Ghofrani HA et al.
Tadalafil 5 mg once daily improves lower urinary tract symptoms suggestive of BPH (long-term study)
McVary KT, Roehrborn CG, Kaminetsky JC et al.
Redefining the role of long-acting phosphodiesterase inhibitor tadalafil in the treatment of diabetic erectile dysfunction.
Bruzziches R, Greco EA, Pili M, Francomano D, Spera G, Aversa A
Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysis.
Gong B, Ma M, Xie W, Yang X, Huang Y, Sun T, Luo Y, Huang J
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Have a question about Tadalafil?
Educational drug info from official sources (PubMed, FDA, EMA). Does NOT replace medical consultation or the SmPC. Talk to your doctor!
The information here is for educational and scientific purposes only. Medication use requires medical consultation and a prescription. The indications, dose ranges, and side effects listed here do NOT replace the official Summary of Product Characteristics (SmPC) or consultation with a physician. Do not start or stop any medication on your own. In an emergency, call your local emergency number.