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. The most common side effects may include: Dry mouth, stomach pain, vomiting, constipation;, Headache, dizziness, spinning sensation;, Mild drowsiness;, Swelling in your hands or feet;, Appetite or weight changes;, Blurred vision;, Sleep problems (insomnia), unusual dreams;, Amnesia, forgetfulness, thinking problems; or, Impotence, loss of interest in sex, or trouble having an orgasm Serious side effects may include: Extreme drowsiness, falling asleep suddenly, even after feeling alert;, Nausea, sweating, feeling light-headed, fainting;, Hallucinations;, Muscle pain, tenderness, or weakness with fever or flu symptoms and dark colored urine;, Chest discomfort, dry cough, feeling short of breath;, Feeling weak or tired, loss of appetite, rapid weight loss;, Fast or uneven heartbeats; or, Tremors, twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs This is not a complete list of side effects and others may occur. Call your doctor for medical advice about additional side effects.