Thank you for your question! If you have concerns about your medication regimen and possible interactions/side effects, you should speak with your prescribing physician. To answer your question, there are no harmful drug-drug interactions between mirtazapine and methoprazine (also called methotrimeprazine). As you know, methoprazine can be used as a sedative. Its possible side effects include dizziness
, drowsiness, decreased mental alertness, nausea, constipation, dry mouth/eyes, blurred vision, and weight gain. Mirtazapine is labeled for use as an antidepressant, although it is commonly used for its sedating and appetite stimulating properties. More than 50% of patients experience drowsiness with this medication (which is often desired when being used for insomnia). Because it also stimulates appetite, weight gain is a common side effect (again, this is sometimes desired depending on the patient). Other possible side effects of mirtazapine include dizziness, constipation, and dry mouth/eyes. It is important to noted that taking too many sedative medications may cause daytime sleepiness
, cognitive slowing, and slowed reaction time. Finally, it is also worth mentioning that both mirtazapine and methoprazine can make patients more prone to having an arrhythmia (due to something called a "prolonged QT interval"). If you are taking both of these medications it would be reasonable to have a baseline EKG
checked to make sure that your QT interval is in a safe range, especially if you have a history of cardiac disease. As mentioned above, I would strongly recommend that you speak with your prescribing physician to learn more about the side effects of these medications, and further cautions to be aware of when taking them.