Doxazosin
Doxazosin. Selective α1-adrenergic blocker — relaxes vascular + prostate smooth muscle. Used for hypertension (less first-line since ALLHAT… Oral half-life 13 h.
Selective α1-adrenergic blocker — relaxes vascular + prostate smooth muscle. Used for hypertension (less first-line since ALLHAT showed worse HF outcomes than thiazides) + symptomatic BPH. First-dose orthostatic hypotension; bedtime dosing recommended.
PK: the half-life of 12.6 h is verbatim, is correctly the HEALTHY-VOLUNTEER subgroup rather than the renal-failure arm or a pooled average, and is confirmed route-independent at about 9 h after both oral and intravenous dosing. F 0.65 is real but belongs to a REVIEW, not to the cited paper, which was oral-only and could not have measured an absolute bioavailability; it is re-attributed and flagged review-grade. V 100 L is dropped as a probable midpoint of a review "1.0 to 1.9 liters/kg". THIS RECORD HAS THE ONE EFFECT-COMPARTMENT VALUE IN ITS GROUP THAT SURVIVES, AND THE AUDIT FOUND A BETTER ANCHOR FOR IT: the stored quote verifies verbatim, but its oral-versus-oral comparison is confounded by absorption, whereas two intravenous studies show blood-pressure effect maximal at 5-6 h AFTER AN INTRAVENOUS DOSE — unambiguous biophase delay with absorption removed. The note claim of "no published keo" is corrected: one was fitted and reported significant, though the rate is not printed. Unusually for this batch, enantiomers are not an issue — racemic, R- and S-doxazosin have indistinguishable potency.
Pharmacokinetics
- Oral — t½ 12.6 h · F 65%
Sources: PMID:2945688, PMID:8905340, PMID:2884857, PMID:6123342, PMID:6135439, PMID:2951051