If you have Huntington's disease, deutetrabenazine can sometimes increase the risk of depression and suicidal thoughts/attempts. People with Huntington's disease are already more likely to have depression and suicidal thoughts/attempts. Talk with your doctor about the risks and benefits of this medication. People with Huntington's disease and depression must not use deutetrabenazine if they are not being treated for depression or if they still have symptoms of depression with medication/treatment. Tell your doctor right away if you or your family/caregivers notice that you have new/worsening symptoms of depression, sadness, loss of interest in activities you used to enjoy, suicidal thoughts/attempts, or other mental/mood/behavior changes (such as new/worsening anxiety, panic attacks, trouble sleeping, irritability, hostile/angry feelings).

Drowsiness, trouble sleeping, tiredness, dizziness, nausea, or vomiting may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Your doctor may need to adjust your dose to reduce these side effects. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. You may notice an empty tablet shell in your stool. This is harmless because your body has already absorbed the medicine. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: agitation/restlessness, Parkinson's disease symptoms (such as shaking/tremors, slowed movement, loss of balance). Sometimes deutetrabenazine can cause side effects that are similar to the symptoms of worsening Huntington's disease. Your doctor may need to adjust your dose to see if these side effects are due to the drug or to the disease. Tell your doctor right away if any of these serious side effects occur: mental/mood changes (such as new/worsening depression, suicidal thoughts/attempts, problems with thinking), trouble swallowing, uncontrolled muscle movements of the face (such as lip smacking, unusual tongue movements), signs of increased prolactin hormone (such as enlarged breasts, abnormal breast milk production, decreased sexual ability, a change in menstrual cycle). This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, muscle stiffness/pain/tenderness/weakness, severe tiredness, severe confusion, sweating, fast/irregular heartbeat, dark urine, signs of kidney problems (such as change in the amount of urine). A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

A product that may interact with this drug is: valbenazine. Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Do not take any MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop taking this medication. Deutetrabenazine is very similar to tetrabenazine. Do not use medications containing tetrabenazine while using deutetrabenazine.