Prazosin
Prazosin. Short-acting selective α1-adrenergic blocker. BP lowering + BPH symptom relief. Off-label for PTSD-related nightmares + sleep… Oral half-life 3 h.
Short-acting selective α1-adrenergic blocker. BP lowering + BPH symptom relief. Off-label for PTSD-related nightmares + sleep disturbance (raised α1 tone in PTSD; prazosin softens hyperarousal during sleep).
PK: VERIFIED, AND MY OWN PRIOR ABOUT IT WAS WRONG. I expected the stored 3 h to be its citation Tmax range endpoint read as a half-life — a clean collision. It is not. An intravenous-plus-oral study states "Terminal half-life (t1/2 beta) was about 3 hr and apparent volume of distribution (Vd beta) about 0.6 l/kg ... total plasma clearance was low (0.14 l/kg x hr)", which at the reference weight is 42 L, 3 h and 9.80 L/h — and the stored pair implies 9.70 L/h, A ONE PERCENT MATCH. The stored {42 L, 3 h} is a TERMINAL volume paired with a TERMINAL half-life, which is the correct one-compartment collapse and the opposite of the defect the rest of this batch is full of. F 0.57 is a STATED MEAN, not a midpoint — "ranges from 43.5 to 69.3% (mean 56.9%)", where the midpoint would be 56.4 — and the same source records that it is formulation- and food-robust. Only the citation was wrong: under the previously cited abstract alone, which says "about 2.5 hours", the same numbers WOULD have been a 1.31x class-12 error. FIRST-DOSE HYPOTENSION IS CORRECTLY ABSENT FROM THE PK, and its own source says why: "Pharmacokinetic data do not suggest a mechanism to explain the disappearance of the first-dose effect." THE OCCUPANCY NOTE NAMES THE WRONG AUTHORS — it credits "Ford 1998" for a paper by Fukasawa, Taniguchi, Moriyama and colleagues. The affinity itself is verbatim and correct, AND THE RECORD AVOIDED A TENFOLD COLLISION AVAILABLE IN THE SAME SENTENCE: it took the human PROSTATE value rather than the human urethra value ten times larger. The effect-compartment note also quotes a 2.5 h half-life that silently contradicts the stored 3 h; both now come from the same intravenous study.
Pharmacokinetics
- Oral — t½ 3 h · F 57% · ka 1.1 h⁻¹ · Vd 42 L
Sources: PMID:6994981, PMID:9839591, PMID:8739810, PMID:7285477