Source: DGNews  |  Posted 1 year ago

By Shazia Qureshi

AMSTERDAM, the Netherlands -- September 3, 2010 -- Amantadine may have similar efficacy to fluoxetine in the treatment of major depressive disorder (MDD), researchers reported here August 31 at the 23rd Congress of the European College of Neuropsychopharmacology (ECNP).

"This study is the first randomised clinical trial to test the antidepressive efficacy of amantadine as monotherapy in unipolar depression versus fluoxetine," the study authors wrote in their poster.

The study was small, including only 49 patients with MDD, and exploratory, since amantadine is not indicated for depression.

Angel Alberto Ruiz-Chow, MD, Department of Neuropsychiatry, National Institute of Neurology and Neurosurgery, Mexico City, Mexico, and colleagues randomised 24 patients (19 women and 5 men) to amantadine treatment and 25 patients (21 women and 4 men) to fluoxetine.

The dose of amantadine given to patients ranged from 100 to 200 mg/day and for fluoxetine the range was 20 to 40 mg/day.

Treatment was double-blinded and lasted 8 weeks. Analysis was by intention to treat.

The investigators found that patients' total scores on the Hamilton Depression Rating Scale improved from the start to the end of the study, falling by 55.5% with fluoxetine treatment and by 58.3% with amantadine treatment (both P = .0001 vs baseline).

Patients' total scores on the Spitzer Quality of Life Index also showed improvement with both drugs, increasing by 45.6% in the amantadine group and by 44.6% in the fluoxetine group (both P = .0001 vs baseline).

The antidepressant effects of the 2 drugs were not significantly different (P = .51).

Nor did the change in patients' Arizona Sexual Experience Scale score differ when comparing amantadine and fluoxetine treatments (P = .33).

Although the number of men as well as the percentage of total patients who were men were both too small to be able to draw conclusions on gender differences, the researchers did find that men responded significantly better to amantadine treatment than to fluoxetine.

No serious adverse events were reported in the study. The dropout rate was 16.6% of patients taking amantadine and 20.8% of patients treated with fluoxetine (P = NS).

"These are interesting results, but larger and longer trials need to be done next," Dr. Ruiz-Chow said.

Funding for this study was provided by Laboratorios Psicofarma SA de CV.

[Presentation title: Amantadine: A Treatment for Major Depressive Disorder. Abstract P.2.a.032]