Fentanyl
Fentanyl, an alkaloid. Synthetic phenylpiperidine μ-opioid agonist; ~100× morphine potency. Lipophilic — fast onset and short duration after… Sublingual half-life 4 h.
Synthetic phenylpiperidine μ-opioid agonist; ~100× morphine potency. Lipophilic — fast onset and short duration after single dose; depot via TD patch enables 72h analgesia. Illicit fentanyl analogs drive most US opioid overdose deaths.
DOSE CORRECTED FROM A DELIVERY RATE STORED AS AN ABSOLUTE DOSE. The TD block read {"min":0.0125,"max":0.1,"typical":0.025,"unit":"mg"}, which is the patch's mcg/hour strength, not the amount it delivers. This row already stores zo_dur_hr, so the wear interval was on the record while the dose contradicted it. Label verbatim: "Each transdermal system is intended to be worn continuously for up to 72 hours". Delivered over the interval that gives 0.864-7.2 mg, typical 1.8 mg — ARITHMETIC, rate x interval. Source: Fentanyl Transdermal System (SpecGx LLC), DailyMed set id e15a7e9b-8025-49dd-9a6d-bafcccf1959f, v58 published 2026-05-06. The strengths are stated in mcg/HOUR — the same label sets dose increments "using the ratio of 45 mg/24 hours of oral morphine to a 12 mcg/hour increase". The old min of 0.0125 mg matched the Duragesic-era 12.5 mcg/h; the cited label says 12. THE CATALOG ALREADY DID THIS RIGHT ELSEWHERE, which is how the defect was spotted: nicotine stores 7-21 mg against a 24 h duration and rivastigmine 4.6-13.3 mg against 24 h, both being what the patch delivers over that interval rather than its hourly rate. EFFECT COMPARTMENT: A RAT VALUE THAT READ AS HUMAN. The rate is verbatim, correctly fitted and correctly attributed — its source reports buprenorphine and fentanyl in ONE SENTENCE, the exact shape that has produced transplants elsewhere in this catalogue, AND THIS RECORD TOOK THE RIGHT HALF OF IT. But the study is rat tail-flick antinociception and the species field was unset, so the value counted among the records claiming a fitted HUMAN keo and was labelled as one on every surface. Declared. The neighbouring buprenorphine record was checked at the same time and is CLEAN: it does not carry this paper's buprenorphine figure at all, citing instead a separate study in healthy volunteers.
Pharmacokinetics
- IV — t½ 4 h · F 100% · Vd 280 L
- Transdermal — t½ 16 h · F 63% · Vd 280 L
- Intranasal — t½ 4 h · F 75% · ka 23.57 h⁻¹ · Vd 280 L
- Sublingual — t½ 4 h · F 79% · ka 3.47 h⁻¹ · Vd 280 L
Sources: PMID:6226471, PMID:7661346, PMID:6214227