Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.
High doses or long-term use of olanzapine can cause a serious movement disorder that may not be reversible. The longer you use olanzapine, the more likely you are to develop this disorder, especially if you are a woman or an older adult.
Call your doctor at once if you have:
uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
trouble speaking or swallowing;
swelling in your hands or feet;
confusion, unusual thoughts or behavior, hallucinations, or thoughts about hurting yourself;
low white blood cell counts--fever, chills, mouth sores, skin sores, sore throat, cough, trouble breathing, feeling light-headed; or
signs of dehydration--feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin;
liver problems--upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
high blood sugar--increased thirst, increased urination, hunger, dry mouth, fruity breath odor, drowsiness, dry skin, blurred vision, weight loss; or
severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.
Common side effects may include:
weight gain (more likely in teenagers), increased appetite;
headache, dizziness, drowsiness, feeling tired or restless;
problems with speech or memory;
tremors or shaking, numbness or tingly feeling;
changes in personality;
dry mouth, or increased salivation;
stomach pain, constipation; or
pain in your arms or legs.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Olanzapine side effects (more detail)
