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Zyprexa Intramuscular Side Effects

Generic Name: olanzapine

Note: This page contains side effects data for the generic drug olanzapine. It is possible that some of the dosage forms included below may not apply to the brand name Zyprexa Intramuscular.

For the Consumer

Applies to olanzapine: oral tablet, oral tablet disintegrating

As well as its needed effects, olanzapine (the active ingredient contained in Zyprexa Intramuscular) may cause unwanted side effects that require medical attention.

Major Side Effects

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
  • 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

Minor Side Effects

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
  • sneezing
  • stomach discomfort, upset, or pain
  • stuffy nose
  • thirst
  • trouble sleeping
  • trouble with concentrating
  • 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

Post-Injection delirium/sedation syndrome, a collection of signs and symptoms consistent with olanzapine (the active ingredient contained in Zyprexa Intramuscular) overdose has been reported following injections of the extended-release IM suspension. Events occurred in less than 0.1% of injections and in approximately 2% of patients receiving injections for up to 46 months. Onset of events ranged from soon after injection to greater than 3 hours later. The majority of patients were hospitalized and some required supportive care, including intubation. Two deaths have been reported occurring 3 to 4 days after receiving the appropriate dose of the extended-release IM suspension. In these patients, very high olanzapine blood levels were reported after death. A study undertaken to determine the cause of the elevated drug levels in these 2 deaths provides inconclusive results. As reported in a 3-23-2015 drug safety communication issued by the US Food and Drug Administration, a study in animals found much of the drug level increases could have occurred after death, but the possibility that the deaths were caused by a rapid, but delayed entry of the drug in to the bloodstream could not be ruled out.

Seizures occurred in 0.15% of patients receiving the IM extended-release suspension and 0.9% of patients receiving oral olanzapine.

Somnolence was reported in 8% of patients receiving IM extended-release suspension.

Sedation was reported in up to 44% of adolescents receiving this drug in short term schizophrenia or bipolar I disorder clinical trials.

When stopping abruptly, discontinuation symptoms such as sweating, insomnia, tremor, anxiety, nausea, and vomiting, have been reported.[Ref]

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]

Collective data gathered from 17 placebo-controlled clinical studies (n=5106) involving the use of atypical antipsychotic agents, including olanzapine, for the treatment of behavioral disorders in the elderly patient with dementia showed a risk of death 1.6 to 1.7 times greater in the drug treated patient than in the placebo treated patient. The average length of duration for the trials was 10 weeks with the cause of death in the majority of cases, though not all, reported as either cardiovascular (e.g., heart failure, sudden death) or infectious (e.g., pneumonia) in nature. Olanzapine is not approved by the FDA for use in the treatment of behavioral disorders in elderly patients with dementia.[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]

Olanzapine appears to have a greater association than some other atypical antipsychotics for increasing glucose levels. Mean increases of up to 15 mg/dL have been reported. The differences in mean changes in serum glucose were higher in patients with evidence of glucose dysregulation at baseline. In an analysis of patients who completed 9 to 12 months of therapy, the rate on increase in mean blood glucose slowed after approximately 6 months.

Clinically significant alterations in lipids have been observed including serum triglyceride elevations greater than 500 mg/dL. In long-term studies of at least 48-weeks in adults, increased from baseline in mean fasting cholesterol, LDL, triglycerides were 5.6 mg/dL, 2.5 mg/dL, and 18.7 mg/dL, respectively. Mean increases in fasting lipid values (total cholesterol, LDL and triglycerides) were greater in patients without evidence of lipid dysregulation at baseline.

In 13 placebo-controlled monotherapy trials, olanzapine-treated patients gained an average of 2.6 kg compared to an average 0.3 kg weight loss in placebo patients; 22.5% gained at least 7% of their baseline weight, 4.2% at least 15% of their baseline (compared to 3% and 0.3% in placebo). Clinically significant weight gain was observed across all baseline BMIs. With longer term exposure (at least 48 weeks), weight gain of 7%, 15%, or 25% or more were reported in 64.4%, 31.7%, and 12.3%, respectively. Weight gain and increased appetite were reported in 30% and 24% of adolescents receiving this drug in short term schizophrenia or bipolar I disorder clinical trials (n=179; placebo patients reported both events at a rate of 6%).[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]

Nausea and dry mouth have been reported to be dose related.

A 65 year old man developed fecal incontinence following initiation of treatment with olanzapine 2.5 mg daily. This effect continued until the patient's next scheduled exam, at approximately 20 days after initiation of therapy, at which point olanzapine was discontinued. Fecal incontinence resolved within approximately 24 hours. No organic cause for fecal incontinence was determined, rectal exam was negative, sigmoidoscopy results were normal, and lab tests were all within normal limits.[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]


Common (1% to 10%): Nasopharyngitis, upper respiratory tract infection, cough, nasal congestion, pharyngolaryngeal pain, sneezing, rhinitis, pharyngitis, pneumonia
Uncommon (0.1% to 1%): Epistaxis
Rare (less than 0.1%): Lung edema[Ref]


Very common (10% or more): hyperprolactinemia
Uncommon (0.1% to 1%): Decreased libido, breast pain[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%): Dry eyes, abnormality of accommodation, amblyopia
Rare (less than 0.1%): Mydriasis[Ref]


Very common (10% or more): Akathisia (up to 27%), asthenia (up to 15%)
Common (1% to 10%): Ear pain, fatigue, pyrexia
Uncommon (0.1% to 1%): Chills[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: Drug reaction with eosinophilia and systemic symptoms (DRESS), rash[Ref]


Very common (10% or more): Insomnia (up to 12%)
Common (1% to 10%): Abnormal dreams, auditory hallucination, restlessness, sleep disorder, abnormal thinking, personality disorder, insomnia
Uncommon (0.1% to 1%): Personality disorder, suicide attempt[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 Zyprexa Intramuscular 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.