Alpha-Blocker (2/5): Doxazosin

Alpha-blocker (1/5): General pharmacology
Alpha-blocker (2/5): Terazosin
Alpha-blocker (3/5): Doxazosin
Alpha-blocker (4/5): Tamsulosin
Alpha-blocker (5/5): Alfuzosin

Review Literatur: (Chapple, 2004).

General Pharmacology of Doxazosin

Please see section general pharmacology of alpha-blocker.

Mechanism of Action of Doxazosin

Doxazosin is a non-selective alpha₁-blocker with a long elimination half-life.

Indications for Doxazosin

Treatment of lower urinary tract symptoms due to benign prostatic hyperplasia
Treatment of arterial hypertension

Pharmacokinetics of Doxazosin

Elimination half-life 22 h

Doxazosin: Mechanism of Action

Postsynaptic alpha₁-blockade leads to:

Arterial and venous vasodilation, hypotension
Smooth muscle relaxation of the prostate, bladder neck and the urethra. Alpha-blocker improve the dynamic component of subvesical obstruction due to benign prostatic hyperplasia (BPH).
Positive effect on the lipid metabolism by lowering cholesterol and triglycerides

Side Effects of Doxazosin

Hypotension, orthostatic syncope, reflex tachycardia
Stuffy nose
Retrograde ejaculation
Tachyphylaxis in the treatment of hypertension due to volume retention and peripheral edema.
Dizziness, weakness
Overall rate of side effects is between 10–30%

Contraindications of Doxazosin

Urological Contraindications:

Conservative treatment of BPH is not indicated, if surgical treatment is imperative: chronic urinary retention with renal failure, recurrent hematuria due to prostatic enlargement, recurrent infections and bladder stones.

Cardiac Contraindications:

Hypotension, mechanical heart failure (valvular, pulmonary embolism, pericarditis), congestive heart failure.

Other contraindications:

Alpha-blocker are contraindicated for cataract surgery, as this may cause an intraoperative floppy iris syndrome.

Dosage of Doxazosin

The treatment of doxazosin should be started with a low dosage, such as 1 mg 1-0-0. The dosage can be increased each week to 2–4–8 mg 1-0-0, depending on treatment effect, side effects and blood pressure.

Terazosin

Index

Tamsulosin

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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References

Chapple 2004 CHAPPLE, C. R.:: Pharmacological therapy of benign prostatic hyperplasia/lower urinary tract symptoms: an overview for the practising clinician.
In: BJU Int
94 (2004), Nr. 5, S. 738–44

Deutsche Version: Doxazosin

Last update

Dr. med. Dirk Manski
man...@urologielehrbuch.de