Tapentadol
Tapentadol. Centrally-acting μ-opioid agonist + norepinephrine reuptake inhibitor — dual mechanism gives analgesic effect with lower opioid… Oral half-life 4 h.
Centrally-acting μ-opioid agonist + norepinephrine reuptake inhibitor — dual mechanism gives analgesic effect with lower opioid receptor occupancy than equipotent morphine, reducing GI side effects. Schedule II. CYP-independent metabolism (UGT2B7) limits DDI footprint.
PK: THE CLEANEST RECORD OF ITS GROUP — three of four values verify against a study with a real 34 mg intravenous arm. F 0.32 is ABSOLUTE and verbatim, and identically 32% for both the immediate- and prolonged-release products, so the formulation ambiguity is harmless here. V 540 L is verbatim under "Following IV administration ... mean tapentadol volumes of distribution were 540 and 471 l" — Study 1 value, NOT a midpoint of the two — so CLASS 6 IS ACQUITTED. The half-life is likewise intravenous-derived. ka 1.5 IS A DIGIT COLLISION: the only 1.5 in that abstract is a time to peak, "a longer time to Cmax (5.0 h vs 1.5 h)" — a Tmax in hours reused as a rate per hour, the first confirmed shape on the collision list. It happens to be nearly serviceable, which is exactly why it survived. ITS EFFECT-COMPARTMENT VALUE IS AN APPROXIMATION OF AN APPROXIMATION: borrowed from hydrocodone, which is itself borrowed from dihydrocodeine miosis — two analogy hops from any measurement, now made visible in that note.
Pharmacokinetics
- Oral — t½ 4 h · F 32% · Vd 540 L
Sources: PMID:31303784, PMID:17656655