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Olanzapine Side Effects

In Summary

Commonly reported side effects of olanzapine include: extrapyramidal reaction, dizziness, weakness, drowsiness, hyperkinesia, mask-like face, cogwheel rigidity, akinesia, dyspepsia, drug-induced parkinson's disease, and xerostomia. Other side effects include: back pain, abnormal gait, fever, constipation, weight gain, orthostatic hypotension, myoclonus, and personality disorder. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to olanzapine: oral tablet, oral tablet disintegrating

As well as its needed effects, olanzapine may cause unwanted side effects that require medical attention.

Severity: Major

If any of the following side effects occur while taking olanzapine, check with your doctor immediately:

More common:
  • Bloating or swelling of the face, arms, hands, lower legs, or feet
  • blurred vision
  • change in vision
  • change in walking and balance
  • clumsiness or unsteadiness
  • difficulty with speaking
  • difficulty with swallowing
  • drooling
  • impaired vision
  • inability to sit still
  • loss of balance control
  • mask-like face
  • muscle trembling, jerking, or stiffness
  • need to keep moving
  • rapid weight gain
  • restlessness
  • shuffling walk
  • slowed movements
  • slurred speech
  • stiffness of the arms and legs
  • tic-like (jerky) movements of the head, face, mouth, and neck
  • tingling of the hands or feet
  • trembling or shaking of the fingers, hands, feet, legs, or arms
  • twisting movements of the body
  • uncontrolled movements, especially of the face, neck, and back
  • unusual weight gain or loss
Less common:
  • Bladder pain
  • bloody or cloudy urine
  • bruising
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • chest pain
  • difficult or labored breathing
  • difficult, burning, or painful urination
  • dizziness
  • excessive muscle tone
  • frequent urge to urinate
  • headache
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • itching of the vagina or genital area
  • lack of coordination
  • large, flat, blue, or purplish patches in the skin
  • loss of bladder control
  • loss of memory
  • lower back or side pain
  • muscle tension or tightness
  • nervousness
  • pain during sexual intercourse
  • pounding in the ears
  • problems with memory
  • rhythmic movement of the muscles
  • shortness of breath
  • slow, fast, pounding, or irregular heartbeat or pulse
  • speaking is less clear than usual
  • sticking out the tongue
  • thick, white vaginal discharge with no odor or with a mild odor
  • tightness in the chest
  • twitching
  • uncontrolled twisting movements of the neck, trunk, arms, or legs
  • unusual or incomplete body or facial movements
  • weakness of the arms and legs

Severity: Minor

Some olanzapine side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Acid or sour stomach
  • back pain
  • belching
  • change in personality
  • difficulty having a bowel movement (stool)
  • discouragement
  • feeling sad or empty
  • fever
  • heartburn
  • increased appetite
  • increased cough
  • indigestion
  • lack of appetite
  • lack or loss of strength
  • loss of interest or pleasure
  • runny nose
  • sleeplessness
  • sneezing
  • stomach discomfort, upset, or pain
  • stuffy nose
  • thirst
  • trouble with concentrating
  • unable to sleep
  • watering of the mouth
Less common:
  • Blemishes on the skin
  • body aches or pain
  • chills
  • cold sweats
  • congestion
  • cough
  • dry skin
  • dryness or soreness of the throat
  • false or unusual sense of well-being
  • heavy menstrual bleeding (periods)
  • hoarseness
  • joint pain
  • lack of feeling or emotion
  • leg cramps
  • pain in the arms or legs
  • pimples
  • sweating
  • tender, swollen glands in the neck
  • uncaring feelings
  • voice change
  • vomiting

For Healthcare Professionals

Applies to olanzapine: intramuscular powder for injection, intramuscular powder for injection extended release, oral tablet, oral tablet disintegrating

Nervous system

Very common (10% or more): Somnolence (up to 44%), headache (up to 18%), sedation (up to 13%), dizziness (up to 18%)
Common (1% to 10%): Post-Injection Delirium/Sedation Syndrome, dysarthria, tremor, hypertonia, abnormal gait, parkinsonism
Uncommon (0.1% to 1%): Seizures, cerebrovascular accident, ataxia, stupor, dystonia, tardive dyskinesia, amnesia
Rare (less than 0.1%): Coma, neuroleptic malignant syndrome, discontinuation symptoms[Ref]


Very common (10% or more): Orthostatic hypotension
Common (1% to 10%): ECG QT-corrected interval prolonged, hypertension, postural hypotension, chest pain, tachycardia, peripheral edema
Uncommon (0.1% to 1%): Syncope-related events, vasodilation, bradycardia
Rare (less than 0.1%): Ventricular tachycardia/fibrillation, sudden death
Postmarketing reports: Venous thromboembolic events[Ref]


Very common (10% or more): Increased weight (up to 30%), increased appetite (up to 24%)
Common (1% to 10%): Elevated cholesterol, elevated glucose, elevated triglycerides
Frequency not reported: Hyperglycemia associated with ketoacidosis or hyperosmolar coma or death
Postmarketing reports: Diabetic coma, diabetic ketoacidosis[Ref]


Very common (10% or more): Dry mouth (up to 22%), constipation (up to 11%), dyspepsia (up to 11%)
Common (1% to 10%): Abdominal pain, diarrhea, flatulence, nausea, toothache, vomiting, toothache
Uncommon (0.1% to 1%): Tongue edema
Rare (less than 0.1%): Ileus, intestinal obstruction
Postmarketing reports: Pancreatitis[Ref]


Common (1% to 10%): Increased hepatic enzymes
Uncommon (0.1% to 1%): Alkaline phosphatase increases, bilirubinemia, hypoproteinemia
Rare (less than 0.1%): Fatty liver deposit
Postmarketing reports: Jaundice[Ref]

Transient, asymptomatic elevations of hepatic transaminases were commonly seen, especially early in treatment.[Ref]


In clinical studies, changes in prolactin levels were found to be statistically significantly different based on dose, higher doses were associated with higher levels of prolactin. In a study of up to 12 weeks, plasma prolactin concentrations exceeded the upper limit of normal (ULN) in approximately 30% of patients who had normal baseline prolactin values. The majority of these elevations were mild, and remained below 2 x ULN.[Ref]


Common (1% to 10%): Ecchymosis, eosinophilia, leukopenia, neutropenia
Uncommon (0.1% to 1%): Thrombocytopenia[Ref]


Uncommon (0.1% to 1%): Hypersensitivity
Postmarketing reports: Allergic reaction[Ref]


Common (1% to 10%): Vaginal discharge
Uncommon (0.1% to 1%): Amenorrhea, decreased/increased menstruation, impotence, menorrhagia, metrorrhagia, polyuria, urinary frequency, urinary retention, urinary urgency, urination impaired
Very rare (less than 0.01%):
Postmarketing reports: Priapism[Ref]


Common (1% to 10%): Arthralgia, back pain, muscle spasms, musculoskeletal stiffness, joint pain, extremity pain
Rare (less than 0.1%): Osteoporosis
Postmarketing reports: Rhabdomyolysis[Ref]


Common (1% to 10%): Acne
Uncommon (0.1% to 1%): Face edema, photosensitivity reaction, alopecia
Postmarketing reports: Rash[Ref]


For the collection of adverse reactions, the term personality disorder was used to collect data on nonaggressive objectionable behavior.[Ref]


The most common adverse reactions associated with the immediate-release products were postural hypotension, constipation, weight gain, dizziness, personality disorder, and akathisia. The most common adverse reactions associated with the extended-release IM injection included headache, sedation, weight gain, cough, diarrhea, back pain, nausea, somnolence, dry mouth, nasopharyngitis, increased appetite, and vomiting.[Ref]


Common (1% to 10%): Injection site pain
Rare (less than 0.1%): Injection site abscess[Ref]


1. FDA. U.S. Food and Drug Administration "Zyprexa Relprevv (olanzapine pamoate): Drug Safety Communication - FDA review of study sheds light on two deaths associated with the injectable schizophrenia drug. Available from: URL:" ([2015 Mar 23]):

2. "Product Information. Zyprexa (olanzapine)." Lilly, Eli and Company, Indianapolis, IN.

3. Cerner Multum, Inc. "Australian Product Information." O 0

4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

5. "Product Information. ZyPREXA Relprevv (OLANZapine)." Lilly, Eli and Company, Indianapolis, IN.

It is possible that some side effects of olanzapine may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.