Intravenous application of amantadine and antiparkinsonian efficacy in Parkinsonian patients.

The aim of this study was to estimate the pharmacokinetic properties of amantadine after infusion and subsequent peroral application of two galenic forms at a daily dose of 200 mg. In addition, the pharmacodynamics of the different treatment regimes evaluated by the motoric items of the UPDRS were investigated. Furthermore, the relationship between plasma levels and clinical efficacy was evaluated. To address these questions Parkinsonian patients were randomly assigned to 3 groups: infusion-tablet, infusion-capsule, infusion-infusion. Parenteral application of amantadine sulphate provided a rapid improvement in Parkinsonian patients within the first three days. This response could be stabilized and even improved further by peroral treatment for another 3 days. The change from intravenous to peroral tablet therapy was followed by a transient decrease in cmax and AUC(o-t) being not reflected by a reduction in clinical efficacy. Conversely, a persistent reduction of the plasma concentration after switching to the capsule therapy was paralleled by a somewhat unfavourable clinical response.