Cialis
[CAS# 171596-29-5]

Identification

• Classification: API >> Hormone and endocrine-regulating drugs >> Treatment of male erectile dysfunction drugs
• Name: Cialis
• Synonyms: (6R,12aR)-6-(1,3-Benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydro-2-methyl-pyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4-dione; Tadalafil
• Molecular Formula: C₂₂H₁₉N₃O₄
• Molecular Weight: 389.40
• CAS Registry Number: 171596-29-5
• EC Number: 687-782-2
• SMILES: CN1CC(=O)N2[C@@H](C1=O)CC3=C([C@H]2C4=CC5=C(C=C4)OCO5)NC6=CC=CC=C36

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H312-H315-H319-H332-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Respiratory sensitization	Resp. Sens.	1	H334
Reproductive toxicity	Repr.	2	H361
Reproductive toxicity	Lact.	-	H362

Discovery and Applications

Discovered in the late 20th century by scientists at the pharmaceutical company ICOS Corporation, Cialis (also known as tadalafil) represented a major advance in medicine. Originally developed to treat cardiovascular conditions such as pulmonary arterial hypertension (PAH), Cialis’ unexpected side effect—enhanced erectile function—led to interest in treating ED.

The distinguishing feature of Cialis is its mechanism of action that sets it apart from other ED medications. Cialis belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, which work by inhibiting the enzyme PDE5 and promoting relaxation of the smooth muscle tissue of the penis. This relaxation increases blood flow to the erectile tissue, which improves erectile function and the ability to achieve and maintain an erection sufficient for sexual activity.

The long-lasting effects of Cialis make it a preferred treatment option for ED. Unlike other PDE5 inhibitors, which are typically effective for a shorter period of time, Cialis can remain active in the body for up to 36 hours, earning it the nickname “the weekend pill.” This extended window of efficacy provides men with greater flexibility and spontaneity, improving their overall satisfaction and quality of life.

Cialis has applications beyond treating ED. In urology, it is used to treat benign prostatic hyperplasia (BPH), a condition characterized by an enlarged prostate. By relaxing the smooth muscle tissue of the bladder and prostate, Cialis helps relieve urinary symptoms such as frequent urination, urgency, and nocturia, improving urine flow and quality of life for patients.

Cialis has potential applications in treating pulmonary arterial hypertension (PAH), a serious condition characterized by high blood pressure in the lungs. By dilating the lung blood vessels and reducing pulmonary vascular resistance, Cialis may improve exercise capacity and quality of life in patients with PAH, providing a valuable treatment option for this life-threatening disease.

Cialis has also been studied for its potential use in other conditions, including Raynaud's phenomenon, a vascular disorder characterized by decreased blood flow to the fingers and toes. Preliminary studies suggest that Cialis may help relieve symptoms and improve blood flow in patients with Raynaud's phenomenon, although further studies are needed to confirm its efficacy.

References

2007. Tadalafil population pharmacokinetics in patients with erectile dysfunction. European Journal of Clinical Pharmacology, 63(6).
DOI: 10.1007/s00228-007-0297-1

2008. Efficacy and safety of tadalafil once daily: considerations for the practical application of a daily dosing option. Current Medical Research and Opinion, 24(12).
DOI: 10.1185/03007990802498440

2010. Addressing and Managing Erectile Dysfunction after Prostatectomy for Prostate Cancer. Urologic Nursing, 30(3).
DOI: 10.7257/1053-816x.2010.30.3.167