Effect of mirtazapine on gastric emptying in patients with skeletal metastasis complaining of cancer related anorexia

Mirtazapine, a tetracyclic antidepressant widely used in cancer patients suffering from anorexia. Though it is known to restore appetite but the exact mechanism remains unknown. Aim of the study was to evaluate, if mirtazapine has any effect on gastric emptying in patients suffering from cancer related anorexic. Gastric emptying study using the 3 h static protocol with radiolabeled solid meal was performed in 30 patients suffering from cancer anorexia once at baseline and repeated after 15 days intake of mirtazapine 7.5 mg orally. Results: Anorexia was reported by all the patients. it was of mild in nature in 3 (10.3%), moderate in 12 (41.4%) and severe in 14 (48.3%) patients., after intervention anorexia was completely resolved in 7 (23.3%), remained mild in 18 (62.1%) and moderate in 4 (13.8%) patient. None of the patients reported severe anorexia after initiation of mirtazapine therapy. At baseline, only 4 (13.8%) patients had gastric emptying >75% whereas after treatment 9 (31.0%) patients achieved this limit. Mean % gastric emptying increased from 55.0 ± 21.7% to 64.5 ± 21.4%, thus showing a statistically significant change in percentage gastric emptying (P = 0.004). Mean gastric emptying time (t_1/2) before intervention was 300.9 ± 428.5 min which decreased to 64.5 ± 21.4 min after intervention. Delayed emptying was present in 25 (83.3%) patient before therapy and in 20 (66.7%). patients after therapy with a P of 0.016. Mirtazapine promptly restores appetite in patients with cancer associated anorexia and this effect is partly due to correction of delayed gastric emptying. (author)