ISSN:
1432-1041
Keywords:
Phenacetin
;
pharmacokinetics
;
liver-first-pass effect
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary The pharmacokinetic characteristics of the analgesic phenacetin have been determined in six healthy adults. After rapid i.v. injection of 250 mg phenacetin, the log plasma concentrations versus time curves were evaluated according to the rules of a two-compartment open model. The elimination half-life (t 1/2) β varied from 37 to 74 minutes. The volume of distribution (Vd) β ranged from 1.0 to 2.1 1 per kg body weight. The total clearance of the drug was high and approximated the average value of hepatic blood flow in normal adults. In agreement with this finding, the bioavailability of a small oral dose of phenacetin (0.25 g) was almost nil, as the bulk of the drug was cleared during its first pass through the liver. With large oral doses (1.0 g) the first-pass effect decreased and availability increased. The results are discussed and related to current general views of the liver-first-pass phenomenon.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00567125
