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Doxazosin: Side Effects and Dosage

Mechanism of Action

Doxazosin is a nonselective α₁-blocker with long elimination half-life. Please see section general pharmacology of alpha blocker. Review Literatur: (Chapple, 2004).

**Structural formula of doxazosin**

Indications for Doxazosin

Treatment of lower urinary tract symptoms due to benign prostatic hyperplasia.
Treatment of arterial hypertension
Off-label treatment of female LUTS due to neurogenic bladder neck obstruction.
Off-label treatment: improve the spontaneous passage of distal ureteral stones.

Pharmacokinetics of Doxazosin

Elimination half-life 22 h

Side Effects of Doxazosin

Increased side effect profile since doxazosin is a nonselective α1 blocker.

Hypotension, orthostatic syncope, reflex tachycardia
Stuffy nose
Retrograde ejaculation
Tachyphylaxis in the treatment of hypertension due to volume retention and peripheral edema.
Dizziness, weakness

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:

Doxazosin should be paused for cataract surgery to prevent an intraoperative floppy iris syndrome.

Dosage of Doxazosin

The treatment of doxazosin should be started with a low dosage, such as 1 mg orally once daily. The dosage can be increased each week to 2–4–8 mg orally once daily, depending on treatment effect, side effects and blood pressure. Doxazosin should be given before bedtime in the evening to reduce side effects.

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

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

J. D. McConnell et al., “The long-term effect of doxazosin, finasteride, and combination therapy on the clinical progression of benign prostatic hyperplasia,” N Engl J Med, vol. 349, no. 25, pp. 2387–98, 2003.

Deutsche Version: Doxazosin