Alpha blocker
Encyclopedia : A : AL : ALP : Alpha blocker
Alpha blockers (also called alpha-adrenergic blocking agents) constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.
Indications
These drugs may be used to treat:- benign prostatic hyperplasia (BPH)
- high blood pressure (hypertension). This is not typically the drug of choice unless the patient also has BPH.
- symptoms of [non inflammatory chronic pelvic pain syndrome], a type of prostatitis. As a side effect they may reduce blood pressure and result in lightheadedness.
Examples of alpha blockers
Alpha blockers include:- Doxazosin (Cardura)
- Prazosin (Minipress)
- Tamsulosin (Flomaxtra/Flomax)
- Terazosin (Hytrin)
Adverse effects and interactions
By reducing α1-adrenergic activity of the blood vessels, these drugs may cause hypotension and interrupt the baroreflex response. In doing so, they may cause dizziness, lightheadedness, or fainting when rising from a lying or sitting posture (known as orthostatic hypotension or postural hypotension). For this reason, it is generally recommended that alpha blockers should be taken at bedtime. Additionally, the risk of orthostatic hypotension may be reduced by starting at a low dose and titrating upwards as needed.Because these medications may cause orthostatic hypotension, as well as hypotension in general, these agents may interact with other medications that increase risk for hypotension, such as other antihypertensives and vasodilators.
As discussed above, tamsulosin may have less risk for hypotension and orthostatic hypotension due to its selectivity for α1a-adrenergic receptors.
References
- [DrugDigest] - Alpha blockers
- [RxList.com] - Tamsulosin
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