Nrc. Campbell et al., METHYLDOPA KINETICS BEFORE AND AFTER INGESTION OF METHYLDOPA FOR 8 WEEKS, European Journal of Clinical Pharmacology, 48(5), 1995, pp. 397-400
Methyldopa urine and plasma levels and urine metabolite levels were as
sessed following intravenous (IV) and oral(PO) methyldopa before, and
after ingestion of methyldopa (500 mg) daily for eight weeks. There wa
s no increase in (estimated) methyldopa absorption (8.4%) or renal cle
arance (PO 13.9%, IV 2.33%) after the eight weeks of methyldopa ingest
ion. However, the initial methyldopa absorption and renal clearance va
lues in this study were higher than in previous studies. There was an
inverse relation between the initial methyldopa absorption and the cha
nge in absorption (r - 0.605) and between the initial methyldopa renal
clearance and the change in renal clearance (PO r - 0.874, IV r - 0.8
91). Overall, this study did not confirm our previous studies showing
induction of methyldopa absorption and renal clearance, possibly due t
o prior up regulation of transporter function. Consistent with methyld
opa inducing drug transporters, those with low initial absorption and
renal clearance values had the greatest increases.