A slow-release oral ketamine tablet has shown promising results in a clinical trial for patients with treatment-resistant depression. The study, led by researchers at the University of Otago in collaboration with Douglas Pharmaceuticals, suggests a potential breakthrough for individuals who have not responded to standard antidepressant therapies.
The trial involved 168 adults with treatment-resistant depression who were administered either varying doses of oral ketamine or a placebo over a 12-week period. Professor Paul Glue from the University of Otago reported that the highest dose of ketamine, 180mg, led to a significant improvement in depressive symptoms compared to the placebo group.
Safety and Tolerability
One of the key advantages of the oral ketamine tablet is its improved tolerability. "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," Prof. Glue explained. "This study shows the extended-release ketamine tablets are safe and effective, and overall, tolerability was good, with participants reporting minimal side effects."
The slow-release formulation releases the drug into the body over a 10-hour period, which is believed to reduce side effects such as high blood pressure, a racing heart, or feelings of numbness.
Clinical Significance
Professor Allan Young of King’s College London, a co-author of the study, highlighted the clinical relevance of the findings. "We're seeing a clinically meaningful effect. This is not a definitive result, but the effect size is gratifyingly large," he stated.
The oral tablet formulation also offers a more convenient and potentially cheaper option for patients. "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," Prof. Glue noted.
Future Research
While the results are encouraging, researchers emphasize the need for further investigation to optimize dosing. Dr. Paul Keedwell, a consultant psychiatrist, pointed out that "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 has also been classified as an illegal recreational drug since the 1980s. The tablet form may also reduce the risk of abuse, according to Prof. Glue.
