Tadalafil: Difference between revisions
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'''Tadalafil''', commonly known by the trade name '''Cialis®''', is a drug used to treat [[erectile dysfunction]]. It is a selective [[phosphodiesterase]] type-5 ([[PDE-5]]) inhibitor that is believed to function in the same way that [[sildenafil]] (Viagra®) and [[vardenafil]] (Levitra®) work, despite significant structural differences.. | '''Tadalafil''', commonly known by the trade name '''Cialis®''', is a drug used to treat [[erectile dysfunction]]. It is a selective [[phosphodiesterase]] type-5 ([[PDE-5]]) inhibitor that is believed to function in the same way that [[sildenafil]] (Viagra®) and [[vardenafil]] (Levitra®) work, despite significant structural differences. | ||
== Mechanism of action == | |||
[[Image:CGMP.jpg|left|thumb|150px|{{#ifexist:Template:CGMP.jpg/credit|{{CGMP.jpg/credit}}<br/>|}}cGMP]] | |||
By competitively binding to PDE-5 enzymes in smooth muscle and therefore inhibiting the binding of cGMP to PDE-5, the degradation of cGMP is reduced resulting in elevated levels of cGMP in the [[corpus cavernosum]] and its supply vessels. The elevated cGMP levels relax the smooth muscles, dilate the [[corporeal sinusoid]]s and increase blood flow enabling an erection. cGMP levels are normally increased during stimulation by the release of [[nitric oxide]] in the corpus cavernosum. The nitric oxide activates guanylate cyclase, an enyme, which produces cGMP. Thus, tadalafil does not enhance the normal mechanism, namely increased synthesis of cGMP, but rather reduces its degradation. | |||
== Chemistry == | |||
== Drug interactions == | |||
Because tadalafil has vasodilator properties that result in decreased blood pressure, the combined use of tadalafil with other vasodilators, such as [[alpha-blocker]]s, must be done cautiously. Patients with a history of [[myocardial infarction|heart attack]]s, [[stroke]]s, [[arrythmia]], [[hypertension]], [[retinitis pigmentosa]] or currently on [[bosentan therapy]] should also be cautious. | |||
== External links == | |||
The most up-to-date information about this and other drugs can be found at the following sites. | |||
*{{DailyMed}} | |||
*{{MedMaster}} | |||
*{{DrugBank}} | |||
== References == | |||
{{cite journal|title=Molecular Biology and Pharmacology of PDE-5-Inhibitor Therapy for Erectile Dysfunction|author=J. D. Corbin and S. H. Sharron|journal=J. Androl.|volume=24|pages=S38-S41}} | |||
Revision as of 14:48, 23 June 2008
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| tadalafil | |||||||
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| Uses: | Erectile Dysfunction | ||||||
| Properties: | PDE-5 inhibitor | ||||||
| Hazards: | cardiovascular risks | ||||||
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Tadalafil, commonly known by the trade name Cialis®, is a drug used to treat erectile dysfunction. It is a selective phosphodiesterase type-5 (PDE-5) inhibitor that is believed to function in the same way that sildenafil (Viagra®) and vardenafil (Levitra®) work, despite significant structural differences.
Mechanism of action
By competitively binding to PDE-5 enzymes in smooth muscle and therefore inhibiting the binding of cGMP to PDE-5, the degradation of cGMP is reduced resulting in elevated levels of cGMP in the corpus cavernosum and its supply vessels. The elevated cGMP levels relax the smooth muscles, dilate the corporeal sinusoids and increase blood flow enabling an erection. cGMP levels are normally increased during stimulation by the release of nitric oxide in the corpus cavernosum. The nitric oxide activates guanylate cyclase, an enyme, which produces cGMP. Thus, tadalafil does not enhance the normal mechanism, namely increased synthesis of cGMP, but rather reduces its degradation.
Chemistry
Drug interactions
Because tadalafil has vasodilator properties that result in decreased blood pressure, the combined use of tadalafil with other vasodilators, such as alpha-blockers, must be done cautiously. Patients with a history of heart attacks, strokes, arrythmia, hypertension, retinitis pigmentosa or currently on bosentan therapy should also be cautious.
External links
The most up-to-date information about this and other drugs can be found at the following sites.
- Tadalafil - FDA approved drug information (drug label) from DailyMed (U.S. National Library of Medicine).
- Template:MedMaster
- Template:DrugBank
References
J. D. Corbin and S. H. Sharron. "Molecular Biology and Pharmacology of PDE-5-Inhibitor Therapy for Erectile Dysfunction". J. Androl. 24: S38-S41.