A significant number of people with depression don’t respond to treatment and become drug resistant. Ketamine helps many but it has to be given intravenously or via a nasal spray, both requiring weekly hospital visits.
It’s known that ketamine has side effects and it can be costly to access, but now a University of Otago-led clinical trial from New Zealand may change all that.
Working in collaboration with New Zealand’s Douglas Pharmaceuticals, researchers have conducted a trial of ketamine using a slow-release tablet.
The study involved 168 adults for whom standard anti-depressant therapy repeatedly failed. They took either a range of oral doses of ketamine or a placebo for 12 weeks.
Otago’s Professor Paul Glue reports that the highest dose of ketamine, 180mg, showed significant improvement in depressive symptoms, compared with patients who received a placebo.
“Ketamine can be given by injection or nasal spray, but these methods can leave people feeling spaced out and sedated, and it increases their blood pressure. This study shows the extended-release ketamine tablets are safe and effective, and overall, tolerability was good, with participants reporting minimal side effects.”
Co-author Professor Allan Young, of King’s College London, said, “We’re seeing a clinically meaningful effect. This is not a definitive result, but the effect size is gratifyingly large.”
The trial used a long-acting form of ketamine that releases the drug into the body over a 10-hour period. The hope was that this would reduce side effects such as high blood pressure, a racing heart or feelings of numbness.
Prof Glue adds: “We have found there are many people, here in New Zealand and around the world, who have treatment-resistant depression, and who have no or very little chance of accessing ketamine.
“Because most doses of this tablet formulation can be taken at home, this is potentially a much cheaper and convenient option for these patients compared with weekly clinic visits for ketamine injections or nasal sprays.”
Dr Paul Keedwell, a consultant psychiatrist, enthused: “This novel study further underlines the impressive anti-depressant effect of ketamine, but in the much more convenient and acceptable form of a slow-release tablet.
“A potential downside of taking oral ketamine is that there are likely to be large individual differences in absorption and metabolism, so further research is needed to determine the ideal dosing regime.”
Ketamine has been used legally by doctors in New Zealand since the 1970s for sedation and pain relief, but classified as an illegal recreational drug since the 1980s.
Furthermore, Prof Glue believes having the drug in a tablet form reduces the risk of abuse.
Great news.