Alpha-Blocker (1/6): General Side Effects and Contraindications
Review Literatur: (Chapple, 2004).
Alpha-Blocker: Mechanism of Action
Postsynaptic alpha1-blockade leads to:
- Arterial and venous vasodilation with reduction of arterial blood pressure. Alpha-blocker are drugs of second choice to treat arterial hypertension.
- Smooth muscle relaxation of the prostate, bladder neck and the urethra. Alpha-blocker are drugs of first choice to improve micturition in patients with benign prostatic hyperplasia (BPH).
- Smooth muscle relaxation of the bladder trigonum and distal ureters. Off-label treatment with alpha-blockers leads to a faster spontaneous passage of distal ureteral stones.
- Following sub-types of alpha1-receptors are known: A, B, D and L. Type alpha1A appears to be most important in the prostate for the inhibition of subvesical obstruction.
Side Effects of Alpha-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
- Overall rate of side effects is between 10–30%, selective alpha1A-blocker have a reduced cardiovascular side effect rate.
Contraindications of Alpha-Blocker
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.
Hypotension, mechanical heart failure (valvular, pulmonary embolism, pericarditis), congestive heart failure.
Alpha-blocker should be paused perioperatively for cataract surgery to prevent an intraoperative floppy iris syndrome.
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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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