Teriparatide
Teriparatide, a peptide. Active N-terminal 34-residue fragment of PTH. Daily intermittent dosing produces ANABOLIC bone effect (osteoblast… Subcutaneous half-life 1 h.
Active N-terminal 34-residue fragment of PTH. Daily intermittent dosing produces ANABOLIC bone effect (osteoblast > osteoclast activation) — opposite to chronic elevated PTH in hyperparathyroidism which drives resorption. Activates PTH1R on osteoblasts → RUNX2 / osteocalcin / type-I collagen production. Reduces vertebral + non-vertebral fracture risk 50–70%. Black-box for osteosarcoma (rat signal, rare in humans).
PK: Satterwhite 2010 (PMID:20953593), 360 postmenopausal women, SC 20 µg daily, verbatim "rapid absorption (maximum concentration achieved within 30 min) and rapid elimination (half-life of 1 h)". The citation is correct and the half-life stands as stored. ka 2.5 /h, V 8.4 L and F 0.95 dropped 2026-09-06 — all three are approval-document figures that appear in no indexed abstract, and the cited paper states none of them. Chu 2007 (PMID:18065105), 9 healthy volunteers, corroborates at 53.9-64.1 min. PK: THE VOLUME WAS IN THE FULL TEXT OF THIS RECORD OWN CITATION, AND STORING IT VERBATIM WOULD HAVE BEEN WRONG. That paper reports "Teriparatide CL/F (approximately 62 l/h, 46% CV)" and "The V/F following subcutaneous administration was approximately 7.8 l (107% CV)" — and THOSE TWO TOGETHER IMPLY A HALF-LIFE OF FIVE MINUTES, against the roughly one hour this record stores and the literature reports for the subcutaneous route. The pair describes fast disposition; the stored half-life is absorption-limited. Storing 7.8 L beside a one-hour half-life would assert a clearance of 5.4 L/h against that paper own 62 — an eleven-fold understatement, the same Vss-against-terminal shape found on sufentanil and vecuronium. The volume stored is instead the VERBATIM CLEARANCE over the rate the stored half-life implies, so exposure reproduces the paper. Bioavailability is pinned at unity because the published quantity is explicitly apparent, which stops the solver dividing by absorption twice. THE SCREEN THAT FOUND THIS READ ABSTRACTS FOR THREE PASSES AND MISSED IT EACH TIME.
Pharmacokinetics
- Subcutaneous — t½ 1 h · F 100% · Vd 89.4 L
Sources: PMID:11346808, PMID:18065105