What medications can cause hallucinations?

Medications That Can Cause Hallucinations

Multiple medication classes can cause hallucinations, including benzodiazepines, corticosteroids, anticholinergics, opioids, antipsychotics, and certain antidepressants. 1

Common Medication Classes Associated with Hallucinations

Anticholinergic Medications

• Medications with anticholinergic properties (e.g., cyclobenzaprine, tricyclic antidepressants, paroxetine) are strongly associated with increased risk of delirium with hallucinations 1
• Specific anticholinergics like diphenhydramine, hydroxyzine, and oxybutynin can induce hallucinations, especially in elderly patients 1

Antipsychotics

• Paradoxically, some antipsychotics can cause hallucinations despite being used to treat them 2
• First-generation antipsychotics like haloperidol (0.5-2 mg) and chlorpromazine (12.5-25 mg) may induce hallucinations 1, 2
• Loxapine and other first-generation antipsychotics have been associated with tactile hallucinations 2

Benzodiazepines

• Benzodiazepines can cause delirium with associated hallucinations, particularly in elderly patients 1, 2
• Abrupt discontinuation of benzodiazepines can also trigger hallucinations as part of withdrawal syndrome 1

Opioids

• Opioids are known to cause hallucinations, particularly at higher doses 1
• Meperidine specifically has a higher risk of causing hallucinations compared to other opioids 1
• Opioid rotation (switching to a different opioid) may help manage hallucinations with 80-90% response rates 2

Corticosteroids

• Corticosteroids are implicated as risk factors for delirium with potential hallucinations 1, 2
• Higher doses and longer duration of treatment increase the risk 2

Antidepressants

• SSRIs can cause complex visual hallucinations, especially when combined with anticholinergic medications 3
• Bupropion can cause hallucinations, particularly during smoking cessation attempts 4
• Tricyclic antidepressants may cause hypnopompic or hypnagogic hallucinations due to their effects on sleep architecture 3
• Serotonin-acetylcholine imbalance (serotonergic hyperactivity with cholinergic hypoactivity) appears to be the mechanism 3, 5

Muscle Relaxants

• Cyclobenzaprine can cause hallucinations due to its anticholinergic effects 1
• Carisoprodol (Soma) has CNS depressant properties that can lead to hallucinations 1

Antiparkinsonian Medications

• Dopamine agonists have greater potential to induce hallucinations compared to L-dopa 6, 7
• Amantadine and anticholinergic antiparkinsonian drugs can trigger hallucinations 6
• Visual hallucinations occur in approximately 40% of Parkinson's disease patients, often triggered by medication changes 6

Risk Factors for Medication-Induced Hallucinations

• Advanced age increases susceptibility to medication-induced hallucinations 1, 2
• Cognitive impairment or dementia significantly raises the risk 3, 6
• Polypharmacy, especially combinations of medications with hallucination potential 1, 2
• Comorbid conditions like infection, dehydration, or metabolic disturbances 6
• Pre-existing psychiatric conditions 2, 5

Management Approach

• Identify and discontinue the offending medication when possible 1
• For antipsychotic-induced hallucinations, consider switching from first-generation to atypical antipsychotics 2, 8
• For opioid-induced hallucinations, consider opioid rotation 2
• Avoid combining multiple medications that can cause hallucinations 2
• Use standardized assessment tools like CAM-ICU or ICDSC when medication-induced hallucinations are suspected 1, 2
• Ensure adequate pain control while minimizing opioid doses, as untreated pain can also contribute to delirium 1

Clinical Pitfalls and Caveats

• Hallucinations may be misattributed to underlying psychiatric conditions rather than medication effects 3, 5
• Abrupt discontinuation of certain medications (benzodiazepines, carisoprodol) can cause withdrawal hallucinations 1
• Elderly patients are particularly susceptible to medication-induced hallucinations due to altered pharmacokinetics and pharmacodynamics 1, 3
• Drug interactions can potentiate hallucination risk, particularly combinations of serotonergic and anticholinergic medications 3
• Monitor for other medication side effects that may accompany hallucinations, such as extrapyramidal symptoms with antipsychotics 2