Which medication is known to be a selective antagonist for Alpha 1 receptors?

The correct response identifies tamsulosin as a selective antagonist for alpha-1 receptors, specifically targeting the alpha-1A subtype that is predominantly found in the prostate and bladder neck. Tamsulosin is commonly used in the treatment of benign prostatic hyperplasia (BPH), where blocking these receptors helps to reduce urinary obstruction and improves urine flow by relaxing smooth muscle in these regions.

In contrast, timolol and betaxolol are both beta-adrenergic blockers, with timolol affecting both beta-1 and beta-2 receptors and betaxolol being a more selective beta-1 blocker, thus they do not exert significant action on alpha-1 receptors. Clonidine, on the other hand, is an alpha-2 adrenergic agonist that decreases sympathetic outflow and is not directly related to blocking alpha-1 receptors. The specificity of tamsulosin for the alpha-1A receptor is what differentiates it as the appropriate choice in this context.