Ketamine slow-release tablet shown to improve depression symptoms

New Delhi, Jun 25 (PTI) Scientists have designed a slow-release form of ketamine tablet which has shown promise in treating depression patients who are resistant to treatment.

Slow-release, or extended-release, tablets are designed to release an active ingredient over time gradually.

Researchers said that the new tablet form releases ketamine, an anaesthetic, into the bloodstream in small amounts and therefore, the patient does not have to experience dissociation to heal from depression.

A dissociative effect of ketamine, which involves hallucinations in the patient, has been considered to be integral to treating depression.

However, the team of researchers from Australia and New Zealand said that one may not have to experience altered perceptions of reality to improve.

"With this tablet form you don't experience that because only a tiny amount is released into the bloodstream at a time, with ongoing slow release over days, and you don't experience the dissociation at all, and yet people are improving," said author Colleen Loo, a clinical psychiatrist and a researcher with the University of New South Wales, Australia.

The study, published in the journal Nature Medicine, revealed the findings of a phase-2 clinical trial of ketamine (of varying dosage), administered as an extended-release tablet.

About 170 patients with treatment-resistant depression were randomly assigned to one of five groups - four receiving different strengths of ketamine, and one receiving placebo.

The researchers found that patients given the strongest dose of ketamine - 180 milligrams, taken orally twice a week - showed the best improvement.

The improvement was measured using the patients' Montgomery-Asberg Depression Rating Scale (MADRS) scores, with higher scores meaning more serious symptoms.

Among patients who received 180 mg, their MADRS scores fell by 14 points on average from a high of 30, whereas in the group receiving placebo, the patients' MADRS scores fell by 8 points on average, the researchers found.

They said that the trial - a double-blinded one where assigning ketamine or placebo to each of the five groups were hidden from both trial administrators and participants - was the first to measure the effectiveness of a slow-release tablet form of ketamine to treat depression.

However, before it becomes an approved clinical treatment, several millions of dollars are needed for further trials, the authors said. PTI KRS VN VN