Comparison of Effectivity and Safety of Olanzapine and Mirtazapine on Cancer-Associated Anorexia and Cachexia in Advanced Oral Cavity Cancer Patients: Prospective, Comparative, Interventional Study

Cancer-associated cachexia-anorexia syndrome (CACS) significantly affects patients' quality of life, leading to weight loss, muscle wasting, and reduced treatment response. This prospective study aimed to evaluate effectiveness of olanzapine versus mirtazapine in managing CACS. Primary objective was to assess their impact on body weight and appetite, while the secondary objective focused on psychological distress and sleep. A total of 152 patients were randomly allocated into two groups of 76 patients each. Group O received Tablet Olanzapine 5 mg/day orally; Group M received Tablet Mirtazapine 15 mg/day orally at bed time. All patients were assessed by using Simplified Nutritional Appetite Questionnaire (SNAQ) score and weight at time of first visit then follow-up visit at 2nd and 4th weeks. At 2nd week, the mean change in SNAQ score was 3.14 in Group M compared to 2.04 in Group O (<i>p</i> = 0.035). By the 4th week, it was 3.86 in Group M and 2.87 in Group O (<i>p</i> = 0.006). Weight changes increased from 45.57 to 46.81 kg in Group M and from 45.97 to 46.90 kg in Group O by 4th week (<i>p</i> ≥ 0.5). Both mirtazapine and olanzapine significantly increased appetite without notable weight gain. Mirtazapine showed stronger effects on appetite, sleep, anxiety, and depression.