A a1 selective adrenergic blocking agents used in benign prostatic hypertrophy is
**Core Concept**
Selective alpha-1 adrenergic blockers are a class of medications used to treat benign prostatic hyperplasia (BPH) by relaxing smooth muscle in the prostate and bladder neck, thus improving urine flow and relieving symptoms. These agents act by blocking alpha-1 adrenergic receptors, which are involved in smooth muscle contraction.
**Why the Correct Answer is Right**
Alpha-1 adrenergic blockers, such as tamsulosin, work by inhibiting the action of norepinephrine on alpha-1 adrenergic receptors in the smooth muscle of the prostate and bladder neck. This leads to relaxation of the smooth muscle and a decrease in the resistance to urine flow. The specific alpha-1 adrenergic receptors targeted by these agents are primarily the A1a subtype, which is found in the human prostate.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a correct answer because it is not a specific example of an alpha-1 adrenergic blocker used in BPH.
**Option B:** This option is not a correct answer because it is not a class of medication used to treat BPH.
**Option C:** This option is not a correct answer because it is not a specific example of an alpha-1 adrenergic blocker used in BPH.
**Clinical Pearl / High-Yield Fact**
It is essential to note that alpha-1 adrenergic blockers can cause orthostatic hypotension as a side effect, particularly in elderly patients or those with pre-existing cardiovascular disease.
**Correct Answer:** C. Tamsulosin