Metoclopramide
Metoclopramide. Dopamine D2 antagonist (CTZ + GI tract) + 5-HT4 agonist + 5-HT3 antagonist. Antiemetic + prokinetic for diabetic gastroparesis.… Oral half-life 5.2 h.
Dopamine D2 antagonist (CTZ + GI tract) + 5-HT4 agonist + 5-HT3 antagonist. Antiemetic + prokinetic for diabetic gastroparesis. EPS + tardive dyskinesia risk → black-box warning at chronic use > 12 weeks.
PK: MOSTLY RIGHT, AND SAYING SO MATTERS. F 0.77 is verbatim ("A mean bioavailability of 0.77 was calculated for the six subjects"), the oral half-life is verbatim at 5.17 h, and V 240 L is 3.43 L/kg x 70 stated in the INTRAVENOUS paragraph — so pairing it with an independent F is CORRECT and the class-6 suspicion is dismissed. The one hard defect is ONE SOURCE NUMBER IN TWO FIELDS: the intravenous row carried the ORAL half-life, while the paper gives that arm its own value, "a mean terminal half-life of 4.55 h +/- 0.80 h". ka 4 is unsourced but is NOT a back-derivation — it implies a 0.88 h peak against the paper stated 0.93 h, whereas solving from that Tmax would have given 3.7 rather than a round 4. Its intramuscular route is declared with no parameters; the crossover that exists confirms it behaves like the oral route but publishes no numbers.
Pharmacokinetics
- Oral — t½ 5.2 h · F 77% · Vd 240 L
- IV — t½ 4.5 h · F 100% · Vd 240 L
Sources: PMID:12593651, PMID:11489465, PMID:7286058, PMID:3964535