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.

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: alcohol, marijuana (cannabis), certain antihistamines (such as diphenhydramine), medicine for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, opioid pain relievers (such as codeine), psychiatric medicines (such as chlorpromazine, risperidone, amitriptyline, trazodone).

Check the labels on all your medicines (such as cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

It is very important for women to use 2 forms of effective birth control while taking this medication. Some drugs may cause hormonal birth control (such as pills, patch, ring) to work less well by decreasing the amount of birth control hormones in your body. This effect can result in pregnancy. Examples include griseofulvin, modafinil, rifamycins (such as rifampin, rifabutin), ritonavir, St. John's wort, drugs used to treat seizures (such as barbiturates, carbamazepine, felbamate, phenytoin, primidone, topiramate), HIV drugs (such as nelfinavir, nevirapine), among others.

Tell your doctor when you start any new drug, and discuss if you should use reliable backup birth control while using the new drug and for 1 month after stopping the new drug.