Dizziness, trouble sleeping, nausea, or headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. An empty tablet shell may appear in your stool. This effect is harmless because your body has already absorbed the medication. If your doctor has prescribed this medication, remember that 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: fast/irregular/pounding heartbeat, shaking (tremor), mental/mood changes (such as anxiety, confusion, nervousness, restlessness), problems urinating. Get medical help right away if you have any very serious side effects, including: seizures. 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.

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking 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 treatment with this medication. Ask your doctor when to start or stop taking this medication. Check the labels on all your medicines (such as cough-and-cold products) because they may contain similar ingredients (decongestants such as phenylephrine). Ask your pharmacist about using those products safely. This medication may interfere with certain lab tests (such as allergy skin testing), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.