Flomax mechanism of action?

Flomax (tamsulosin) mechanism of action:

- It is a selective antagonist of alpha-1 adrenergic receptors, mainly α1A and α1D subtypes.
- These receptors are abundant in the smooth muscle of the prostate, bladder neck, and urethra.
- By blocking α1A/α1D, tamsulosin relaxes the smooth muscle in the bladder outlet and prostatic urethra, reducing urethral resistance and improving urine flow.
- It does not shrink the prostate or treat the underlying cause of BPH; it relieves the dynamic component of obstruction.
- Because it is relatively selective for α1A/α1D over α1B (which is more vascular), it tends to cause less orthostatic hypotension than nonselective alpha blockers, though fainting/dizziness can still occur, especially with the first dose.