See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug (or levodopa) include: certain drugs used to treat high blood pressure (such as methyldopa), tetrabenazine.

Taking MAO inhibitors with this medication (along with a levodopa-containing product) may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. However, certain MAO inhibitors (rasagiline, safinamide, selegiline) may be used with careful monitoring by your doctor. Ask your doctor when to start or stop taking this medication.

This medication (or levodopa) may interfere with certain lab tests (such as urine catecholamine/glucose/ketone tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.