FDA-approved indications

• Treatment of depressive episodes associated with bipolar I disorder in adults and in children and adolescents 10–17 years old.
• Treatment of major depressive disorder in adults who have not responded adequately to at least two different antidepressants (treatment-resistant depression).

Off-label uses (clinician-directed)
Clinicians may occasionally use the combination off-label for severe or complex mood disorders (for example, certain difficult-to-treat unipolar or bipolar depressions), but evidence is more limited than for the approved uses, and these decisions are individualized.

Efficacy expectations and onset

• Some people notice improved sleep or anxiety within 1–2 weeks, but mood and energy improvements often take 2–6 weeks, and full benefit may take longer.
• In bipolar depression and treatment-resistant depression, studies show higher response and remission rates than with fluoxetine alone for many patients, though not everyone responds.
• Compared with other antidepressant or antipsychotic options, this combination can be very effective for depressive symptoms but tends to cause more weight gain and metabolic side effects than many alternatives.

Typical dosing and how to take

• Given by mouth once daily, usually in the evening because it can cause drowsiness.
• Capsules are swallowed whole with water and can be taken with or without food.
• Doses vary by indication and age; clinicians usually start with a lower strength and adjust gradually based on response and tolerability.

Special dosing instructions

• Dose adjustments may be needed in people with certain liver problems, those taking interacting medications, or those sensitive to side effects.
• Do not change the dose or stop the medicine suddenly without medical guidance, as symptoms may return or withdrawal effects may occur.

Missed dose guidance
If a dose is missed, take it as soon as remembered unless it is close to the time of the next dose; if it is almost time for the next dose, skip the missed dose and resume the regular schedule without doubling up.

Overdose
Signs of overdose can include extreme drowsiness, confusion, agitation, fast or irregular heartbeat, fainting, seizures, or breathing problems; in any suspected overdose, seek emergency medical care or contact poison control immediately.

Common side effects

• Very common: sleepiness, increased appetite, weight gain, dry mouth, constipation, dizziness, fatigue.
• Other frequent effects: restlessness or inner jitteriness (akathisia), tremor, blurred vision, sexual dysfunction, sweating, nausea or diarrhea.
• These often start in the first days to weeks of treatment; some improve over time, but weight and metabolic changes can persist or worsen without management.

Serious or rare adverse effects (seek urgent care)

• Signs of high blood sugar or diabetes (excessive thirst or urination, unexplained weight loss, fruity breath) or very high triglycerides.
• Serotonin syndrome (agitation, confusion, fever, sweating, fast heart rate, stiff or twitching muscles, diarrhea) especially when combined with other serotonergic drugs.
• Neuroleptic malignant syndrome (high fever, severe muscle stiffness, confusion, autonomic instability).
• Tardive dyskinesia (repetitive, uncontrollable movements of face, tongue, or limbs).
• Severe allergic or skin reactions, liver problems (yellowing of skin or eyes, dark urine), seizures, or severe low sodium (confusion, headache, weakness, seizures).

Warnings and precautions

• Antidepressants can increase suicidal thoughts and behaviors in children, adolescents, and young adults, especially early in treatment or after dose changes; close monitoring is needed.
• Antipsychotic-containing products increase the risk of death in older adults with dementia-related psychosis and are not approved for this use.
• Use caution in people with diabetes, high cholesterol, obesity, liver disease, seizure disorders, bipolar mania history, low blood pressure, or a history of glaucoma.
• Pregnancy: use only if the potential benefit justifies the risk; late-pregnancy exposure may cause newborn adaptation symptoms (jitteriness, feeding or breathing problems).
• Breastfeeding: both medicines can pass into breast milk; the decision to breastfeed while taking this drug should be made with a clinician.

Comparative safety
Compared with many standard antidepressants, this combination carries a higher risk of weight gain, elevated blood sugar, and lipid changes because of the olanzapine component, but its psychiatric benefits may justify these risks in carefully selected patients.

Side-effect reporting and safety updates
Patients can report side effects to their prescriber, pharmacist, or directly to the FDA MedWatch program by phone or online, and clinicians follow FDA safety communications for new warnings or guidance related to this medicine.

Prescription and OTC drug interactions

• Do not use with monoamine oxidase inhibitors (MAOIs), linezolid, or intravenous methylene blue, and allow required washout periods before starting or stopping these drugs.
• Other serotonergic medicines (SSRIs, SNRIs, triptans, tramadol, many migraine or pain medicines, lithium, St. John's wort) increase the risk of serotonin syndrome.
• Drugs that affect heart rhythm (certain antipsychotics, antiarrhythmics, some antibiotics) may increase QT prolongation risk when combined.
• Fluoxetine strongly inhibits CYP2D6, which can raise levels of some beta-blockers, certain antidepressants, antipsychotics, and other CYP2D6 substrates.
• Smoking can reduce olanzapine levels (via CYP1A2 induction), so starting or stopping smoking can change drug levels.
• Nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, and other blood thinners may increase bleeding risk when combined with fluoxetine.

Food, alcohol, and supplements

• Alcohol can significantly increase drowsiness and impair judgment and coordination; it is generally best to avoid or minimize alcohol while taking this medicine.
• St. John's wort and other serotonergic supplements should be avoided due to serotonin syndrome risk.
• No major specific food restrictions are required, but monitoring diet is important because of the tendency toward weight gain and metabolic changes.

Conditions requiring special precautions

• Use caution or dose adjustments in people with liver impairment, seizure disorders, a history of mania or hypomania, diabetes or prediabetes, high cholesterol, cardiovascular disease, or low blood pressure.
• Inform eye doctors before certain eye procedures, as this medicine may contribute to angle-closure glaucoma risk in susceptible individuals.

Monitoring needs

• Regular checks of weight, waist circumference, blood pressure, fasting blood glucose (or A1c), and lipid profile are recommended, especially during the first months of treatment.
• Clinicians monitor for new or worsening suicidal thoughts, mood changes, movement symptoms, and signs of high blood sugar or metabolic problems.
• Additional tests such as liver function tests or ECGs may be ordered based on individual risk factors or co-medications.

Q: How long does it take for olanzapine and fluoxetine to start working?
A: Some people feel better sleep or less anxiety within 1–2 weeks, but meaningful mood improvement often takes 2–6 weeks or longer, and your clinician may adjust the dose over time to get the best effect.

Q: Will I gain weight on this medication?
A: Weight gain is common, especially in the first few months, so your provider may recommend diet, exercise, and regular monitoring of weight, blood sugar, and cholesterol to help manage this risk.

Q: Can I stop taking olanzapine and fluoxetine if I feel better?
A: Do not stop on your own; your clinician will usually recommend continuing for a period of stability and, if appropriate, gradually tapering to reduce the risk of relapse or withdrawal symptoms.

Q: Is it safe to drink alcohol while taking this medicine?
A: Alcohol can increase drowsiness and impair thinking and coordination, so it is generally best to avoid or limit alcohol and discuss any use with your clinician.

Q: What should I do if I feel very restless, have unusual movements, or feel much more agitated?
A: Contact your clinician promptly or seek urgent care, as these symptoms could indicate side effects such as akathisia, movement disorders, or mood changes that may require dose adjustment or a change in treatment.

Storage
Store capsules at room temperature (generally 68°F to 77°F / 20°C to 25°C), away from moisture, heat, and direct light, and keep the bottle tightly closed.

Keep out of reach of children and pets, and do not store in the bathroom where humidity is high.

Disposal
Do not use capsules past the expiration date or if they are damaged; follow local take-back or pharmacy drug-disposal programs when possible.

If no take-back option is available, mix unused capsules (do not crush open) with an undesirable substance (such as used coffee grounds or kitty litter), place the mixture in a sealed container, and throw it in the household trash according to local guidelines.