ATC Code C02KX07, G04BE08
Formula C22H19N3O4
Molar Mass (g·mol−1) 389,404
Physical State solid
Melting Point (°C) 301-302
PKS Value 0,85
CAS Number 171596-29-5
PUB Number 110635
Drugbank ID DB00820
Solubility sparingly soluble in water


Tadalafil is a vasodilator and blood pressure-lowering phosphodiesterase-5 inhibitor and is used to treat erectile dysfunction, benign enlargement of the prostate, and pulmonary hypertension.
Im Gegensatz zu anderen ähnlich wirkenden Medikamenten wie z.B. Sildenafil (Viagra) hat Tadalafil eine bessere und länger anhaltende Wirkung und eignet sich mehr für die tägliche Dosierung.



Tadalafil inhibits the enzyme phosphodiesterase-5, which delays the breakdown of the neurotransmitter cGMP. This in turn triggers a relaxation of the smooth muscle in the penis, causing the blood vessels to dilate and allowing more blood to flow into the corpus cavernosum. As a result, an erection can be produced or maintained longer and stronger.

The drug also causes the smooth muscle of the pulmonary vessels to relax, lowering blood pressure in the pulmonary arteries.

In benign enlargement of the prostate, tadalafil reduces smooth muscle cell growth, helping to reduce prostate size and relieve symptoms.


The maximum plasma concentration of tadalafil is reached after approximately 2 hours and is 94% bound to plasma proteins. The half-life is 15-17.5 hours. In the liver, the drug is metabolized by the enzyme CYP3A4 and excreted mainly in the stool and 30% in the urine.

Drug Interactions

Since tadalafil enhances the antihypertensive effects of nitrates, NO donors, amyl nitrite, and other antihypertensive agents, the agents should not be used concomitantly.
Mit Arzneimitteln die auch durch das CYP3A4 abgebaut werden, können ebenfalls Wechselwirkungen auftreten.


Side effects

Possible side effects include headache, dizziness, dyspepsia (upper abdominal discomfort), back pain, infection of the pharyngeal mucosa, and facial flushing, as well as low blood pressure and visual disturbances.

Toxicological data

Symptoms of overdose are similar to typical side effects.

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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