Pramipexole
Pramipexole. Non-ergot dopamine agonist with preferential affinity for the D3 receptor (within the D2 receptor family); first-line for… Oral half-life 13 h.
Non-ergot dopamine agonist with preferential affinity for the D3 receptor (within the D2 receptor family); first-line for Parkinson's disease and restless legs syndrome.
PK from FDA prescribing information (DailyMed setid 46f88017-7b0e-437e-90b1-37bdf9013e72): absolute bioavailability >90% (F 0.9), apparent Vd ~500 L, terminal t½ ~8 h (young)/~12 h (elderly), Tmax ~2 h, ~90% excreted unchanged in urine. ka_hr 1.5 derived from Tmax 2 h (ke from t½ 8 h). Human D2 affinity not authored — GtoPdb's curated human range (pKi 5.1–7.4) is too wide to pin a value. PK: THE LABEL ROW HAD A REAL PRIMARY IT WAS PARAPHRASING. Sixteen healthy volunteers, four dose levels: "The mean volume of distribution and elimination half-life for all participants was 486 +/- 93.2 L and 12.9 +/- 3.27 hours". The stored 8 h is contradicted by that and by a second study at 9.85 h; it was the label young-subject figure. That volume is from a STEADY-STATE ORAL study, so it is apparent and F is pinned to 1 rather than double-dividing; the label >90% is retained here as prose, and deliberately NOT upgraded to the one literature statement available, because that is a REVIEW quoting an inequality bound and citing it would dress a bound as a measurement. THE RECORD SIMPLE-KINETICS PREMISE VERIFIES: "renal clearance of pramipexole accounts for approximately 80% of oral clearance". ka 1.5 back-derives to 2.017 h, EXACTLY the label Tmax. Caveat carried: the primary cohort included women and clearance tracks creatinine clearance, so 12.9 h is not a young-male figure.
Pharmacokinetics
- Oral — t½ 12.9 h · F 100% · Vd 486 L
Sources: PMID:7756621, PMID:9208359