Pharmacokinetics of baclofen in spastic patients receiving multiple oral doses
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The pharmacokinetics of racemic baclofen as determined from plasma and urine data in six spastic patients treated with individualized oral doses, 30–80 mg daily, are presented. Peak plasma concentrations were achieved 1.9 h (±0.7) after a dose. The fluctuation in the plasma concentration was great, ranging from 188 to 439%. The total body clearance averaged 175 ml·min−1 (±44), plasma protein binding 35% (±6). Baclofen was for the greater part excreted unchanged by the kidney, 65% (±16). Its apparent renal clearance equalled the creatinine clearance. The contribution of the renal clearance to the total body clearance can explain the previously described toxicity when renal impairment is present. The results agree with earlier reports on single doses in healthy subjects.
KeywordsBaclofen Clearance Patients Pharmacokinetics
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- 2.Peterson GM, McLean S, Millingen KS. Food does not affect the bioavailability of baclofen. Med J Aust 1985;42:689–90.Google Scholar
- 3.Krauss D. Untersuchungen zur Razemat- und Enantiomerenkinetik von Baclofen und seinen Fluoranalogons [Disssertation]. Frankfurt am Main: Goethe-Universität, 1988.Google Scholar
- 12.Anderson P, Nohér H, Swahn CG. Pharmacokinetics in baclofen overdose. Clin Toxicol 1984;22:11–20.Google Scholar
- 16.Pedersen E. How spasticity affects bowel and bladder function. In: Feldman RG, Young RR, Koella WP, eds. Spasticity. Disordered motor control. Chicago: Year Book Medical Publishers, 1980:57–69.Google Scholar
- 17.Wuis EW, Dirks MJM, Termond EFS, Vree TB, Van der Kleijn E. Comparison of the pharmacokinetics of intravenously administered rac-baclofen and its (−)-(R)- and (+)-(S)-enantiomers in dogs. Int J Clin Pharm Res 1989;10:239–46.Google Scholar