ATC Group: G04CA Alpha-adrenoreceptor antagonists

Anatomical Therapeutic Chemical Classification System

Hierarchical position in ATC classification

Level
Code
Title
1
Genito urinary system and sex hormones
2
Urologicals
3
Drugs used in benign prostatic hypertrophy
4
G04CA
Alpha-adrenoreceptor antagonists

ATC group contents

Code
Title
Alfuzosin
Tamsulosin
Terazosin
Silodosin
Alfuzosin and finasteride
Tamsulosin and dutasteride
Tamsulosin and solifenacin
Tamsulosin and tadalafil

Active ingredients

Active Ingredient
Description

Alfuzosin is an orally active quinazoline derivative. It is a selective, peripherally acting antagonist of postsynaptic alpha-1-adrenoceptors. In vitro pharmacological studies have documented the selectivity of alfuzosin for the alpha-1-adrenoreceptors located in the prostate, bladder base and prostatic urethra.

Silodosin is highly selective for α1A-adrenoreceptors that are primarily located in the human prostate, bladder base, bladder neck, prostatic capsule and prostatic urethra. Blockade of these α1A-adrenoreceptors causes smooth muscle in these tissues to relax, thus decreasing bladder outlet resistance, without affecting detrusor smooth muscle contractility.

Tamsulosin binds selectively and competitively to post-synaptic α1-adrenoreceptors, prevailingly their subtypes designated α1A and α1D. Thus relaxation of smooth muscles of the prostate and urethra is achieved, which leads to a reduction of tonus and an improvement of the urinary flow.

Although the exact mechanism of the hypotensive action is not established, the relaxation of peripheral blood vessels appears to be produced mainly by competitive antagonism of post-synaptic alpha-adrenoceptors. Terazosin usually produces an initial gradual decrease in blood pressure followed by a sustained antihypertensive action.

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