Most medications can cause side effects which can be defined as an unwanted response to a medication when it is taken in normal doses. Side effects can range from mild or severe, temporary or permanent. Side effects are not experienced all patients who take this medication. Many side effects can be managed, and others may go away over time. Common side effects may include extreme tiredness, dizziness, confusion, headache, sleepiness, constipation, vomiting, coughing and pain anywhere in your body, especially your back. Serious side effects may include cough, chest tightness, fever, trouble breathing; chest pain, fast heart rate; confusion, hallucinations; sudden numbness or weakness, especially on one side of the body; lack of coordination; fainting or seizure (convulsions); urinating less than usual or not at all; pale skin, easy bruising or bleeding, unusual weakness; or increased blood pressure (severe headache, blurred vision, trouble concentrating, chest pain, numbness, seizure). Get emergency medical attention if you have any signs of an allergic reaction (hives; difficulty breathing; swelling of your face, lips, tongue, or throat). Stop using NAMENDA immediately and call your doctor at once if you experience any of the above noted serious side effects. This is not a complete list of side effects and others may occur. Call your doctor for medical advice about additional side effects that you may experience.