Drowsiness, dizziness, constipation, flushing, nausea, nervousness, blurred vision, or dry mouth may occur as your body adjusts to the medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. 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: high fever, decreased sexual ability, severe stomach/abdominal pain, difficult/painful swallowing, difficulty urinating, weakness. Get medical help right away if you have any very serious side effects, including: chest pain, severe dizziness/fainting, fast/irregular/slow heartbeat, mental/mood changes (such as confusion, hallucinations, memory problems), eye pain/swelling/redness, vision changes (such as seeing rainbows around lights at night). 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.

Some products that may interact with this drug are: potassium tablets/capsules, pramlintide. Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine). Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely. This medication may interfere with certain medical/lab tests (including brain scan for Parkinson's disease), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.