Methylphenidate
Methylphenidate, a stimulant. Blocks DAT + NET — increases synaptic DA + NE without the TAAR1-mediated vesicular release of amphetamines. More… Oral half-life 3.7 h.
Blocks DAT + NET — increases synaptic DA + NE without the TAAR1-mediated vesicular release of amphetamines. More selective for cortical than striatal DA transporters at therapeutic doses → lower peripheral effect than amphetamines. d-threo isomer (dexmethylphenidate) is the active stereoisomer.
PK: this record doses the RACEMATE in mg, so its F must be per mg of racemate, not per mg of the active enantiomer. Srinivas 1993 (PMID:8430051), 11 healthy adults with an IV arm, states both halves verbatim — "the absolute bioavailability (F) of d-MPH was 0.23 and that of l-MPH was 0.05" — and a 1:1 racemate therefore delivers (0.23 + 0.05)/2 = 0.14 of the dose as circulating methylphenidate. The stored 0.3 over-predicted systemic exposure roughly twofold. Half-life 3 h -> 3.74 h (PMID:20861586, "For IR MPH, the half-life was 3.74 hours", 30 healthy adults 18-68 y); the stored value came from a review's "2 to 3 hours" range. ka and V dropped as unsourced. The previous citation (PMID:25274428) is a fed, steady-state, extended-release bioequivalence study stating none of the four values. NOTE: the l-isomer is destroyed presystemically by CES1 and does not alter d-MPH disposition once absorbed, so elimination is shared with dexmethylphenidate while absorption is not.
Pharmacokinetics
- Oral — t½ 3.7 h · F 14%
Sources: PMID:10628897, PMID:17228864, PMID:8430051, PMID:20861586, PMID:26729760