Dozens of commonly prescribed and over-the-counter medications can cause hallucinations, and the list extends well beyond the drugs most people would suspect. Corticosteroids, sleep aids, certain antibiotics, blood-pressure pills, opioid painkillers, epilepsy drugs, and even cough syrups have all been documented as triggers. Most drug-induced hallucinations are visual, though auditory and tactile experiences also occur depending on which brain pathways the medication affects. The phenomenon is more common than many patients and even some clinicians realize, in part because people who experience it while taking a “normal” medication often hesitate to mention it.
Why So Many Different Drugs Can Produce the Same Side Effect
Hallucinations are not a quirk of one brain chemical going haywire. Research has identified at least three distinct pharmacological routes to producing them: boosting dopamine activity, stimulating serotonin receptors (particularly the 5-HT2A receptor), and blocking glutamate NMDA receptors.1PubMed Central. Pharmacology of hallucinations: several mechanisms for one single symptom? A fourth route involves disrupting the brain’s acetylcholine system, which is how anticholinergic drugs produce their characteristic delirium-like states. Because these pathways overlap and interact, a medication designed to treat one condition can accidentally tip the balance toward perceptual distortions. The serotonin 5-HT2A receptor, for example, appears to be involved across several unrelated drug classes, from Parkinson’s treatments to certain antidepressants.2The European Journal of Psychiatry. Drug-induced hallucination: A case/non case study in the French Pharmacovigilance Database That shared receptor involvement is part of why the same strange side effect can show up in drugs that otherwise have nothing in common.
Anticholinergic Medications
Anticholinergic drugs block the neurotransmitter acetylcholine, and they are everywhere in medicine: overactive-bladder pills, certain antihistamines, some muscle relaxants, pre-surgical agents like atropine and scopolamine, and older antidepressants. These drugs are competitive antagonists at muscarinic receptors in the brain, and when they hit the central nervous system hard enough, they can produce vivid, often frightening hallucinations alongside confusion, agitation, and delirium.3ACS Chemical Neuroscience. DARK Classics in Chemical Neuroscience: Atropine, Scopolamine, and Other Anticholinergic Deliriant Hallucinogens The hallucinations tend to be visual and disorganized. People sometimes describe seeing insects, strangers in the room, or objects that shift and distort.
Most clinicians learn that anticholinergic psychosis happens only when doses exceed the therapeutic range. That is usually true, but not always. Case reports have documented psychotic episodes, including hallucinations, in patients taking standard prescribed doses, particularly when multiple anticholinergic drugs are combined.4PubMed Central. Anticholinergic medications even in therapeutic range can cause recurrence of psychosis Older adults are at higher risk because aging naturally reduces acetylcholine levels, so the same dose packs a bigger punch. The broader neuropsychiatric picture can include anxiety, seizures, bizarre behavior, and coma in severe cases.5PubMed Central. Neuropsychiatric manifestations due to anticholinergic agents and anabolic steroids ingestion: A case series and literature review
Parkinson’s Disease Medications
Levodopa, the cornerstone of Parkinson’s treatment, is one of the best-known medication-related causes of hallucinations. The drug works by increasing dopamine in the brain, which is exactly what Parkinson’s patients need to control tremor and stiffness, but the same dopamine boost can generate perceptual disturbances. Visual hallucinations are the most common form, and patients frequently report seeing people, animals, or vivid colors that are not there.6PubMed. Early dopaminergic drug-induced hallucinations in parkinsonian patients These hallucinations can appear early in treatment, not just after years of use.
The tricky part is that many patients do not volunteer this information. They may worry about being labeled confused or mentally ill, or they may not even connect the visions to their medication. Clinicians are advised to ask specifically about visual hallucinations at every follow-up visit because the side effect is potentially reversible with dose adjustment.7PubMed Central. Visual hallucinations in the elderly associated with the use of levodopa In some cases, the hallucinations are mild and non-threatening enough that patients choose to tolerate them rather than reduce a dose that controls their tremor. That is a decision best made with your doctor, but it should be made knowingly.
Sleep Medications
Zolpidem, sold under the brand name Ambien, is probably the most widely prescribed sleep aid linked to hallucinations. It belongs to a class called Z-drugs, which act on the same brain receptors as benzodiazepines but were initially marketed as having fewer side effects. Reported adverse reactions include hallucinations, sensory distortions, sleepwalking, and nocturnal eating.8The Primary Care Companion for CNS Disorders. Adverse Reactions to Zolpidem: Case Reports and a Review of the Literature The hallucinations typically appear shortly after taking the pill or upon waking in the middle of the night, and they tend to be brief, lasting roughly fifteen to twenty minutes in some documented cases.9PubMed Central. Zolpidem-induced Hallucinations: A Brief Case Report from the Indian Subcontinent
These episodes can be alarming because the person may be in a twilight state between sleep and wakefulness, making it hard to distinguish the hallucination from a dream. What separates this from a nightmare is that the person is physically moving, eyes open, and sometimes interacting with the hallucinated content. If you have experienced anything like this on a sleep medication, it is worth mentioning to whoever prescribed it. Adjusting the dose or switching to a different drug usually resolves the problem.
Corticosteroids
Prednisone, dexamethasone, and other glucocorticoids are prescribed for everything from asthma flares to autoimmune disease to organ transplant rejection. They are remarkably effective anti-inflammatory drugs, but they come with a long list of psychiatric side effects that many patients are not warned about. Serious neuropsychiatric effects, including hallucinations, delusions, mania, and severe mood disturbances, occur in roughly six percent of patients who receive steroids.10PubMed. The neuropsychiatric complications of glucocorticoid use: steroid psychosis revisited The single biggest predictor of trouble is the dose: the higher the dose, the greater the risk. The effects are largely unpredictable in terms of who will be affected, but reducing the dose typically leads to recovery.
In a review of steroid-induced psychosis cases, hallucinations and delusions were the most common presentations, and most patients required an antipsychotic medication to manage symptoms until the steroid could be tapered.11PubMed Central. Pharmacological Management of Steroid-Induced Psychosis: A Review of Patient Cases This is worth knowing if you are being prescribed a high-dose steroid course for an acute illness. The psychiatric effects do not mean you are developing a mental illness; they are a pharmacological side effect that resolves when the drug is withdrawn or reduced.
Antibiotics
This one surprises most people. Several classes of antibiotics are associated with psychosis and hallucinations, and the risk varies substantially by class. A large pharmacovigilance study found that fluoroquinolones (such as ciprofloxacin and levofloxacin) and macrolides (such as azithromycin and clarithromycin) had particularly elevated odds of psychotic adverse reactions compared to a reference antibiotic. Cephalosporins and penicillins also showed increased risk, while aminoglycosides did not.12Brain, Behavior, & Immunity – Health. Psychosis as an adverse effect of antibiotics When the researchers looked specifically at hallucinations across sensory modalities, the same pattern of risk held.
Fluoroquinolones have received the most regulatory attention for neuropsychiatric side effects, and the FDA has added warnings to their labels. But macrolides also carry meaningful risk. If you develop odd perceptual experiences, paranoia, or confusion while on an antibiotic, it is not all in your head. Or rather, it is, but the antibiotic put it there. Bringing it up with your prescriber early can lead to a switch to a different antibiotic that finishes the job without the psychiatric side effects.
Opioid Painkillers
Opioids can cause hallucinations through a phenomenon called opioid-induced neurotoxicity, which also involves excessive sleepiness, confusion, delirium, muscle twitching, and paradoxically increased pain sensitivity.13BMJ Supportive & Palliative Care. Opioid-induced neurotoxicity in palliative medicine: a rapid review Much of the published literature on this problem comes from end-of-life and cancer pain settings, where patients receive high or escalating doses over extended periods.14PubMed Central. Opioid-induced Hallucinations: A Review of the Literature, Pathophysiology, Diagnosis, and Treatment But hallucinations can occur at lower doses too, particularly in older patients, those with kidney impairment (which slows drug clearance), or people taking multiple sedating medications at once.
The hallucinations from opioids are often visual and can range from benign to deeply distressing. In a hospital or hospice setting, they may be mistaken for delirium from the underlying illness rather than recognized as a medication effect. When possible, the standard approach is to reduce the opioid dose or rotate to a different opioid, since individual drugs in the class vary in how much neurotoxicity they produce for a given person.
ADHD Stimulants
Psychostimulants such as methylphenidate and amphetamine-based medications carry a small but real risk of triggering psychotic symptoms, including hallucinations. A large study across two insurance-claims databases found that among more than 220,000 patients newly started on a stimulant, psychosis occurred in about one to three per thousand person-years of exposure. Amphetamines carried roughly sixty-five percent higher risk than methylphenidate.15PubMed Central. Psychosis with Methylphenidate or Amphetamine in Patients with ADHD The typical time from first dose to the psychotic episode was about four months, meaning this is not always an immediate reaction.
A separate study looking specifically at children and adolescents taking methylphenidate found no statistically significant increase in psychotic events during treatment compared to baseline. Interestingly, there was a spike in psychotic events during the ninety days before treatment was started, which the researchers interpreted as possible prodromal symptoms that led to the clinical visit in the first place.16Translational Psychiatry. Methylphenidate and the risk of psychotic disorders and hallucinations in children and adolescents in a large health system The overall risk remains low, but it is one reason stimulant prescriptions carry warnings about new psychotic symptoms.
Antidepressants
Antidepressants can cause hallucinations in two distinct scenarios. The first is during active use: certain SSRIs, including escitalopram, have been linked to visual and auditory hallucinations in patients without dementia or any prior psychotic history.17PubMed. Escitalopram-related visual and auditory hallucination in a non-dementia patient with depression The second scenario is discontinuation. When patients stop paroxetine, whether abruptly or after a gradual taper, some develop visual and auditory hallucinations as part of a broader withdrawal syndrome that can also include dizziness, headache, insomnia, and nausea.18PubMed. Hallucination induced by paroxetine discontinuation in patients with major depressive disorders
The discontinuation hallucinations tend to show up within a couple of days after stopping or sharply reducing the medication. Paroxetine has the shortest half-life among the commonly used SSRIs, which is why it is the most frequent offender in withdrawal-related symptoms. If you are planning to stop an antidepressant, a slow taper supervised by your prescriber is the standard way to minimize the chance of these effects. And if hallucinations develop after stopping a medication, knowing that discontinuation syndrome exists can save you a panicked trip to the emergency department, though you should still contact your prescriber promptly.
Anticonvulsants
Topiramate, widely prescribed for epilepsy, migraine prevention, and increasingly for weight management, is the anticonvulsant most clearly associated with hallucinations. Psychotic symptoms, including auditory hallucinations and paranoid delusions, have appeared as early as two days and as late as six weeks after starting the drug, at doses ranging from 50 to 400 milligrams per day.19Seizure. Acute psychotic symptoms induced by topiramate In most reported cases, symptoms resolved quickly once topiramate was discontinued or the dose was reduced. Average daily doses associated with hallucinations have been reported around 150 milligrams in women and 181 milligrams in men, though cases at doses as low as 50 milligrams daily have occurred.20PubMed. Hallucinations Associated with Topiramate Therapy: A Case Report and Review of the Literature
This matters especially now that topiramate is being prescribed more broadly for weight loss and migraine. Many of the patients receiving it have no history of epilepsy or psychiatric illness, and they may be less likely to have a psychiatric screening before starting the drug. If you develop unusual perceptual experiences after starting topiramate, the medication should be considered a possible cause even at a low dose.
Cardiovascular Drugs
Beta-blockers, commonly prescribed for high blood pressure, heart rhythm disorders, and anxiety, can cause central nervous system side effects including hallucinations. The risk is best established with lipophilic beta-blockers such as propranolol, which cross the blood-brain barrier more easily. Visual hallucinations have also been reported with metoprolol, though less frequently.21PubMed Central. Metoprolol-induced visual hallucinations: a case series The hallucinations tend to be visual, sometimes described as seeing shadowy figures or geometric patterns. Because beta-blockers are so commonly prescribed and the psychiatric effects are relatively rare, many patients and doctors do not make the connection between the medication and the experience.
Ketamine and Other Anesthetics
Ketamine has a well-documented tendency to produce hallucinations, vivid dreams, and a dissociative state as patients emerge from sedation. This so-called emergence phenomenon occurs in up to fifty-five percent of patients who receive ketamine and closely mimics symptoms of psychosis, including euphoria, illusions, delirium, and hallucinations.22PubMed Central. Pharmacogenetics of Ketamine-Induced Emergence Phenomena: A Pilot Study The frequency of this reaction has made some emergency physicians reluctant to use ketamine despite its advantages as a rapid-acting sedative and pain reliever.23PubMed Central. Does Haloperidol Prophylaxis Reduce Ketamine-Induced Emergence Delirium in Children?
With the growing use of ketamine and esketamine for treatment-resistant depression, these psychotomimetic effects have become a practical concern beyond the operating room. Patients receiving ketamine infusions in psychiatric clinics are typically monitored during and after treatment precisely because of the high rate of perceptual disturbances. The hallucinatory effects usually resolve within an hour after the infusion ends, but they can be unsettling if you are not expecting them.
Over-the-Counter Cough and Cold Products
Dextromethorphan (DXM), the cough suppressant found in many pharmacy-aisle cold remedies, acts on NMDA glutamate receptors in a way that is pharmacologically similar to ketamine and PCP. At recommended doses it is a straightforward cough suppressant. At high doses, typically well above 150 milligrams (the therapeutic dose for cough is around 90 to 120 milligrams per day), it can produce dissociative hallucinations, delusions, and paranoia.24PubMed Central. Dextromethorphan in Cough Syrup: The Poor Man’s Psychosis 25Egyptian Journal of Forensic Sciences. Deaths due to abuse of dextromethorphan sold over-the-counter in Pakistan
While intentional abuse is the most common pathway to DXM-induced hallucinations, accidental overmedication can also produce neuropsychiatric symptoms, particularly in young children. A case report described a two-year-old who developed agitation, psychosis, and loss of coordination after being given too much of a pseudoephedrine and dextromethorphan combination product.26PubMed. Dextromethorphan- and pseudoephedrine-induced agitated psychosis and ataxia: case report For parents measuring out children’s cough medicine at three in the morning, the margin between a therapeutic dose and a problematic one is narrower than it is for adults. Following the dosing instructions on the label carefully, and using the included measuring device rather than a kitchen spoon, matters more than most people realize.
Dietary Supplements and Herbal Products
Herbal and dietary supplements occupy a regulatory gray area, and some have been linked to psychotic symptoms including hallucinations. One published case described a man who developed a six-month course of escalating psychotic symptoms while taking five different dietary supplements, ultimately requiring involuntary hospitalization. The complexity of supplement-induced psychiatric effects is compounded by the fact that products may contain undisclosed ingredients, interact unpredictably with each other, and vary in potency between manufacturers and even between batches from the same manufacturer.
Because supplements are not held to the same testing standards as prescription drugs, the evidence base for their psychiatric side effects is thinner and mostly limited to case reports. That does not mean the risk is negligible. If you are taking multiple supplements and develop unusual perceptual experiences, mood changes, or paranoid thinking, it is worth considering whether the supplements could be contributing. This is something many patients forget to mention to their doctor, since supplements are often mentally categorized as “natural” and therefore harmless.
Who Is Most Vulnerable
Several factors increase the likelihood that a given medication will cause hallucinations in a given person. Age is the most consistent one: older adults are more susceptible across nearly every drug class discussed here, partly because the brain becomes more sensitive to certain pharmacological effects with age and partly because kidney and liver function decline, meaning drugs stay in the body longer. Taking multiple medications simultaneously, a situation that is the norm rather than the exception for many older adults, further raises the risk by creating additive effects on the brain’s neurotransmitter systems.
Pre-existing neurological conditions also lower the threshold. People with Parkinson’s disease, Lewy body dementia, or a history of psychotic disorders are more prone to medication-induced hallucinations. Dehydration, sleep deprivation, and acute medical illness such as infection can also make the brain more vulnerable. In hospital settings, where patients are often sleep-deprived, dehydrated, and receiving several new medications at once, drug-induced hallucinations are common enough that they sometimes get attributed to “hospital delirium” without anyone identifying the specific medication at fault.
What to Do If You Suspect a Medication Is Causing Hallucinations
The most important step is straightforward: tell whoever prescribed the medication. Do not stop a medication abruptly on your own, because sudden withdrawal from some drugs (benzodiazepines, certain antidepressants, anticonvulsants) can itself cause hallucinations or seizures. Your prescriber can assess whether the hallucinations are likely drug-related, adjust the dose, or switch to an alternative. In most cases, drug-induced hallucinations resolve once the offending medication is reduced or discontinued.
Keep a timeline. Note when the hallucinations started relative to when you began the medication or had a dose change. This information is enormously helpful for your doctor. Also mention every medication and supplement you are taking, including over-the-counter products. People often think of their blood pressure pill or their sleep aid as too mundane to mention, but as the evidence shows, mundane medications are fully capable of producing extraordinary perceptual effects.