Octreotide
Octreotide, a peptide. Cyclic octapeptide with a disulfide bridge (Cys-2 – Cys-7) and D-Phe, D-Trp, Thr-ol modifications — producing 30×… Subcutaneous half-life 1.5 h.
Cyclic octapeptide with a disulfide bridge (Cys-2 – Cys-7) and D-Phe, D-Trp, Thr-ol modifications — producing 30× longer t½ than native somatostatin (1.5 h vs 2 min) and SSTR2 > SSTR5 selectivity. Suppresses GH + IGF-1 (acromegaly), inhibits hormone release from functional neuroendocrine tumours (carcinoid, VIPoma, glucagonoma), and reduces portal pressure acutely (variceal bleeding). LAR formulation: biodegradable PLGA microspheres release drug over ~4 weeks.
PK: Kutz 1986 (PMID:2876508), 8 healthy subjects, IV and SC, supports the 1.5 h half-life as a rounded central value of the stated ranges — "second half-lives of from 72 +/- 22 min to 98 +/- 37 min" (IV) and "The disposition half-life was from 88 +/- 20 min to 102 +/- 16 min" (SC). The ka of 2 /h was dropped 2026-09-06 as CONTRADICTED rather than merely unsourced: the same abstract states subcutaneous absorption "with a half-life ranging from 5.3 +/- 2.2 min to 11.7 +/- 7.6 min", implying 3.6-7.8 /h. V 21 L dropped — no primary states an octreotide volume; the 18-30 L range comes from a review (PMID:8287633). THE IM ROW WAS THE REAL DEFECT: it cited a study of a SUBCUTANEOUS depot and carried the immediate-release half-life. Intramuscular octreotide is the LAR depot, whose half-life is 169 h — Chen 2000 (PMID:10806600), 22 subjects, single 30 mg IM, verbatim "the apparent half-life (t1/2) was 169 hours" — roughly 113 times the value stored. Beware the coincidence in that abstract: its Cmax arrives "approximately 1.5 hours after dosing", a time to peak for the initial burst, not a half-life.
Pharmacokinetics
- Subcutaneous — t½ 1.5 h
- IV — t½ 1.5 h
- Intramuscular — t½ 7.0 d
Sources: PMID:2876508, PMID:10806600, PMID:8287633