Can Mounjaro (Tirzepatide) Cause Hallucinations?
Mounjaro (tirzepatide) is not documented to cause hallucinations based on available pharmacovigilance data and clinical trial evidence. If a patient on Mounjaro develops hallucinations, you should immediately conduct a comprehensive medication review and evaluate for alternative causes rather than attributing this symptom to the drug itself.
Evidence Base for Tirzepatide Safety Profile
The established adverse event profile of tirzepatide does not include hallucinations or neuropsychiatric symptoms of this nature 1, 2. The most common adverse events are gastrointestinal (nausea 17-22%, diarrhea 13-16%, vomiting 6-10%), which are mild to moderate in severity 2. Serious adverse events occurred in only 5-7% of patients in the SURPASS-2 trial, with no mention of hallucinations or psychotic symptoms 2.
Systematic Approach When Hallucinations Occur
If your patient on Mounjaro develops hallucinations, follow this algorithmic approach:
Step 1: Medication Review
Screen specifically for these common culprits 3, 4:
- Anticholinergic medications
- Corticosteroids
- Dopaminergic agents (e.g., for Parkinson's disease)
- Benzodiazepines
- Other psychoactive medications
Step 2: Evaluate Metabolic and Medical Causes
Assess for the following conditions 3:
- Electrolyte imbalances
- Hypoxia
- Sepsis or systemic infection
- Poorly controlled pain
- Delirium from any cause
Step 3: Vision Assessment
Conduct formal ophthalmologic examination 5, 4:
- Document any degree of vision loss
- Consider Charles Bonnet syndrome if vision impairment exists (affects 15-60% of visually impaired patients) 5
- Charles Bonnet syndrome presents with recurrent vivid visual hallucinations, preserved insight, and absence of other neurological explanations 5
Step 4: Neurological Evaluation
Look for red flags requiring alternative diagnosis 5:
- Lack of insight despite education about hallucinations
- Hallucinations that interact with the patient
- Accompanying neurological signs
- Consider brain MRI and evaluation for dementia with Lewy bodies, Parkinson's disease, or primary psychiatric disorders 5
Step 5: Oncologic Considerations
In patients with cancer history, evaluate for 3:
- CNS involvement from malignancy
- Paraneoplastic syndromes
- Delirium from underlying disease progression
Important Caveats
One case report exists describing autoimmune encephalitis (anti-NMDA receptor) following tirzepatide use, presenting with seizures, agitation, and psychiatric symptoms 6. However, this represents an extremely rare event with unclear causality, and the mechanism is poorly understood 6. This should not be considered a typical adverse effect but rather an isolated case requiring further investigation.
Do not reflexively prescribe antipsychotics for hallucinations in patients on Mounjaro without completing the diagnostic workup outlined above 5, 4. The hallucinations are almost certainly from another cause, and antipsychotics carry significant risks, particularly in elderly patients (extrapyramidal symptoms, tardive dyskinesia) 7.
Class Effect Considerations
GLP-1 receptor agonists and dual GIP/GLP-1 agonists like tirzepatide have not been documented to cause hallucinations in pharmacovigilance literature 3. This is not a class effect of incretin-based therapies 3. The safety profile remains consistent with gastrointestinal side effects as the primary concern 7, 1, 8.