Effects of joint administration of imipramine and amantadine in patients with drug-resistant unipolar depression.

Abstract

The paper describes the effect of amantadine (AMA) supplementation on imipramine (IMI) therapy in patients (with treatment-resistant unipolar depression) who fulfilled DSM IV criteria for major depression. Twelve patients were enrolled to the study on the basis of history of their illness and therapy. Following 2 weeks of washout period, the patients were treated with IMI twice daily (100-150 mg/day) for 6 weeks, and then AMA was introduced (twice daily, 100-150 mg/day) and administered jointly with IMI for further 6 weeks. Thereafter, AMA was withdrawn, and the patients were treated with IMI alone for 2 weeks. Hamilton Depression Rating Scale (HDRS) and Beck Depression Inventory (BDI) were used to assess efficacy of antidepressant therapy. IMI changed neither HDRS nor BDI score after 3 or 6 weeks of treatment when compared with washout (before treatment). AMA supplementation significantly reduced both HDRS and BDI scores after 3- or 6-week supplementation. AMA augmentation of IMI treatment was beneficial and lasted even after AMA withdrawal. Moreover, pharmacokinetic data indicate that AMA did not influence significantly the plasma concentration of the IMI and its metabolite, desipramine, in the patients during joint treatment with AMA and IMI, what suggests the lack of pharmacokinetic interaction. These results suggest that joint therapy with IMI and AMA may be successful in the treatment-resistant unipolar depression.