olanzapine
(oh lan' za peen)
Zyprexa, Zyprexa IntraMuscular, Zyprexa Zydis
Pregnancy Category C
Drug classes
Antipsychotic
Dopaminergic blocking agent
Therapeutic actions
Mechanism of action not fully understood; blocks dopamine receptors in the brain, depresses the RAS; blocks serotonin receptor sites; anticholinergic, antihistaminic (H1), and alpha-adrenergic blocking activity may contribute to some of its therapeutic (and adverse) actions; produces fewer extrapyramidal effects than mostantipsychotics.
Indications
· Treatment of schizophrenia
· Treatment of acute mixed or manic episodes associated with bipolar 1 disorder and maintenance of bipolar 1 disorder as monotherapy, or combined with lithium or valproate
· Treatment of agitation associated with schizophrenia and bipolar 1 mania (injection)
· Unlabeled use: Dementia related to Alzheimer's disease
Contraindications and cautions
· Contraindicated with allergy to olanzapine, myeloproliferative disorders, severe CNS depression, comatose states, lactation.
· Use cautiously in elderly or debilitated patients, or with CV or cerebrovascular disease, dehydration, seizure disorders, Alzheimer's disease, prostate enlargement, narrow-angle glaucoma, history of paralytic ileus or breast cancer, pregnancy; phenylketonuria (if using orally disintegrating tablets, contain phenylalanine).
Available forms
Tablets—2.5, 5, 7.5, 10, 15, 20 mg; orally disintegrating tablets—5, 10, 15, 20 mg; powder for injection—10 mg
Dosages
ADULTS
· Schizophrenia: Initially, 5–10 mg PO daily, increase to 10 mg PO daily within several days; may be increased by 5 mg/day at 1-wk intervals to achieve desired effect. Do not exceed 20 mg/day.
· Bipolar mania: 10–15 mg/day PO; adjust at 5-mg intervals as needed, not less than q 24 hr. Maximum dose, 20 mg/day. For maintenance, 5–20 mg/day PO. The initial dose is 10 mg of olanzapine when combined with lithium or valproate.
· Agitation: 10 mg IM; range 5–10 mg IM; dose may be repeated in 2 hr if needed, safety of > 30 mg/24 hr not established.
PEDIATRIC PATIENTS
Safety and efficacy not established in patients < 18 yr.
GERIATRIC PATIENTS
5 mg IM.
DEBILITATED PATIENTS
Start with initial dose of 5 mg; 2.5 mg IM.
Pharmacokinetics
Route | Onset | Peak | Duration |
Oral | Varies | 6 hr | Weeks |
IM | Rapid | 15–45 min | Weeks |
Metabolism: Hepatic; T1/2: 30 hr
Distribution: Crosses placenta; enters breast milk
Excretion: Feces, urine
Adverse effects
· CNS: Somnolence, dizziness, nervousness, headache, akathisia, personality disorders, tardive dyskinesia, neuroleptic malignant syndrome
· CV: Orthostatic hypotension, peripheral edema, tachycardia
· GI: Constipation, abdominal pain
· Respiratory: Cough, pharyngitis
· Other: Fever, weight gain, joint pain, development of diabetes mellitus
Interactions
Drug-drug
· Increased risk of orthostatic hypotension with antihypertensives, alcohol, benzodiazepines; avoid use of alcohol and use caution with antihypertensives
· Increased risk of seizures with anticholinergics, CNS drugs
· May decrease effectiveness of levodopa, dopamine agonists
· Decreased effectiveness with rifampin, omeprazole, carbamazepine, smoking
· Increased risk of toxicity with fluvoxamine
Nursing considerations
CLINICAL ALERT!
Name confusion has occurred between Zyprexa (olanzapine) and Zyrtec (cetirizine); use caution.
Assessment
· History: Allergy to olanzapine, myeloproliferative disorders, severe CNS depression, comatose states, history of seizure disorders, lactation; CV orcerebrovascular disease, dehydration, Alzheimer's disease, prostate enlargement, narrow-angle glaucoma, history of paralytic ileus or breast cancer, elderly or debilitated patients, pregnancy
· Physical: T, weight; reflexes, orientation, IOP, ophthalmologic examination; P, BP, orthostatic BP, ECG; R, adventitious sounds; bowel sounds, normal output, liver evaluation; prostate palpation, normal urine output; CBC, urinalysis, LFTs, renal function tests
Interventions
· Do not dispense more than 1-wk supply at a time.
· Peel back foil on blister pack of disintegrating tablets; do not push through foil; use dry hands to remove tablet and place in mouth.
· Prepare solution for IM injection using 2.1 mL sterile water for injection. Resulting solution contains 5 mg/mL. Solution should be clear yellow. Use within 1 hr of reconstitution. Discard any unused portion.
· Monitor for the many possible drug interactions before beginning therapy.
· WARNING: Monitor elderly patients for dehydration and institute remedial measures promptly; sedation and decreased sensation of thirst related to CNS effects of drug can lead to dehydration.
· Encourage patient to void before taking the drug to help decrease anticholinergic effects of urinary retention.
· Monitor for elevations of temperature and differentiate between infection and neuroleptic malignant syndrome.
· Monitor for orthostatic hypotension and provide appropriate safety measures as needed.
Teaching points
· Take this drug exactly as prescribed; do not change dose without consulting your health care provider.
· Peel back foil on blister pack of disintegrating tablets; do not push through foil; use dry hands to remove tablet, place entire tablet in mouth.
· This drug cannot be taken during pregnancy. If you think you are pregnant or wish to become pregnant, contact your health care provider.
· You may experience these side effects: Drowsiness, dizziness, sedation, seizures (avoid driving, operating machinery, or performing tasks that require concentration); dizziness, faintness on arising (change positions slowly, use caution); increased salivation (if bothersome, contact your health care provider); constipation (consult with your health care provider for appropriate relief measures); fast heart rate (rest and take your time if this occurs).
· Report lethargy, weakness, fever, sore throat, malaise, mouth ulcers, and flulike symptoms.
Adverse effects in Italic are most common; those in Bold are life-threatening.
1 comments:
Thanks for sharing this really informative post ! Information you have given is quite beneficial for readers and for those who are recommended to have this medicine named Olanzapine.
Would love to read more !
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