Effect of Mirtazapine on Gastric Emptying in Patients with Cancer-associated Anorexia

BACKGROUND/AIMS: The tetracyclic antidepressant mirtazapine is widely used in cancer patients suffering from anorexia. Although it is known to restore appetite, the exact mechanism remains unknown. The aim of the study was to evaluate if mirtazapine has any effect on gastric emptying in patients suffering from cancer-related anorexia. MATERIALS AND METHODS: Solid-meal gastric-emptying study using radiolabeled meal was performed in 28 patients suffering from cancer anorexia once at baseline and repeated after 15 days of mirtazapine therapy. RESULTS: At baseline, only 7 (25%) patients had normal gastric motility (emptying >70% at 3 h postingestion) whereas after treatment, 18 (64.2%) patients achieved this limit. Mean % gastric emptying increased from 55.2% ±21.0% to 68.9% ±21.3% (P < 0.001). Mean gastric emptying time (t(1/2)) before intervention was 314.7 ± 421.0 min which decreased to 116.0 ± 106.7 min after intervention. Results were further analyzed by dividing the patients into two groups based on baseline gastric-emptying study. Group A (normal gastric emptying) consisted of seven patients, mean % gastric emptying at baseline and postintervention was 75.0% ±5.25% and 87.57% ±5.94%, respectively (P < 0.018). Group B (delayed gastric emptying) consisted of 21 patients, mean % gastric emptying at baseline and postintervention was 48.71% ±18.82% and 62.76% ±16.86%, respectively (P < 0.001). CONCLUSION: Mirtazapine significantly improves gastric emptying in patients of prostate and breast cancer suffering from cancer-associated anorexia.