Olanzapine-Samidorphan for Schizophrenia: A Systematic Review and Meta-Analysis
Schizophrenia and bipolar disorder are serious mental health conditions that affect how people think, feel, and behave on the daily basis. Schizophrenia involves patients who have auditory/visual hallucinations, delusions, and disorganized thoughts and behaviors. Bipolar disorder sees patients with extreme mood swings that can include emotional highs (like in a manic phase) and lows (depression). Olanzapine is a second-generation atypical antipsychotic medication that works on the 5HT2A receptor, that aids in helping patients with schizophrenia and bipolar disorder. One of the main drawbacks to long-term Olanzapine use is that it gives rise to weight gain and diabetes mellitus. Samidorphan is an opioid receptor modulator that is a mu-opioid receptor and a partial agonist at the kappa and delta opioid receptors (which help toward weight loss). The combination of Olanzapine-Samidorphan was approved a few years back, so I wanted to look at how efficacious the drug was against Olanzapine monotherapy.
The authors implemented a systematic review and meta-analysis of Olanzapine-Samidorphan. A literature search through the PubMed, Embase, and Cochrane Library databases brought back 6 randomized controlled trials with a total of 1,655 patients who were given either Olanzapine monotherapy or the combination of Olanzapine-Samidorphan. The outcomes that were assessed included how efficacious the combination drug was against Olanzapine monotherapy, the proportion of patients with weight gain at the end of the study, incidences of somnolence, dry mouth, headache, any adverse events, or incidences of serious adverse events (SAEs) at the end of the study.
Olanzapine monotherapy and Olanzapine-Samidorphan were equally efficacious in keeping the symptoms of schizophrenia at bay. More patients gained more weight with Olanzapine monotherapy than they did with the combination drug (23.6% vs. 19.6%). There were more incidences of somnolence, dry mouth, and headaches in the Olanzapine-Samidorphan group than there were in the monotherapy group. Olanzapine monotherapy had more incidences of adverse events and serious adverse events (including hyperglycemia, dyslipidemia, increase in waist circumference, and metabolic syndrome) over the Olanzapine-Samidorphan group.
Although the sample size of their study was not the largest (1,655 patients), the authors concluded that the combination drug of Olanzapine-Samidorphan offered clinical efficacy to patients who needed to take an antipsychotic medication for their schizophrenia or bipolar disorder. The combination drug was just as efficient in keeping the symptoms of the patient’s mental disorder at bay and it kept the weight off as well. The increased incidences of dry mouth, somnolence, and headaches were most likely due to side effects of Samidorphan.
