Many common medications can worsen confusion and cognitive problems in older adults and people with dementia, even when the drugs are being used exactly as prescribed. This happens because certain medications interfere with the brain’s ability to process information, regulate mood, or maintain alertness. Anticholinergic drugs (which block a brain chemical called acetylcholine), sedating medications, and opioid painkillers are among the most frequent culprits.

For example, an older adult taking an over-the-counter antihistamine like Benadryl for allergies, combined with a prescription sleeping pill, may experience noticeable confusion or memory problems within days—symptoms that often get mistaken for early dementia when the real cause is the medication combination. The link between medications and confusion is dose-dependent and cumulative, meaning that both the strength of each drug and the total number of medications a person takes play a role. Someone taking one anticholinergic medication might notice mild fuzzy thinking, but someone taking three or four drugs with anticholinergic properties—perhaps without realizing it—can experience severe disorientation, hallucinations, or delirium. This is why understanding which medications carry this risk, how they interact, and what warning signs to watch for is essential for anyone managing their own health or caring for someone else.

Which Common Medications Have Anticholinergic Effects?
How Benzodiazepines and Sedating Medications Impair Cognition
Opioid Painkillers and Cognitive Side Effects
Recognizing Medication-Induced Confusion vs. Dementia
Polypharmacy: When Multiple Medications Create Compounding Risk
Anticholinergic Burden Scales and Clinical Assessment
Managing Medications Safely When Confusion Is a Concern

Which Common Medications Have Anticholinergic Effects?

anticholinergic medications block acetylcholine, a neurotransmitter that helps control memory, attention, and the sleep-wake cycle. Many people don’t realize their drugs have anticholinergic properties because these medications are prescribed for entirely different reasons. Over-the-counter antihistamines like diphenhydramine (Benadryl) and chlorpheniramine (Chlor-Trimeton) are common offenders, as are prescription antihistamines like hydroxyzine. First-generation antidepressants such as amitriptyline and imipramine carry significant anticholinergic burden, as do older antipsychotic medications.

Even some blood pressure drugs and urinary incontinence treatments have anticholinergic effects. The problem is that many patients and even some physicians don’t connect these medications to cognitive changes because the drugs are being used for legitimate conditions. A person taking an anticholinergic antidepressant for anxiety, an anticholinergic medication for bladder control, and an over-the-counter sleep aid may experience sudden confusion or memory lapses—but if each doctor prescribing these drugs doesn’t see the full medication list, no one recognizes the accumulation of anticholinergic exposure. This is why maintaining an updated, complete medication list (including supplements and over-the-counter products) and reviewing it regularly with a pharmacist or physician is critical.

How Benzodiazepines and Sedating Medications Impair Cognition

Benzodiazepines such as lorazepam (Ativan), diazepam (Valium), and alprazolam (Xanax) directly suppress brain activity and are particularly risky for older adults and anyone with existing cognitive concerns. These drugs were never intended for long-term use, yet many people have been taking them daily for years. Even at low doses, benzodiazepines impair memory formation, slow reaction time, and increase the risk of delirium and falls. A 72-year-old who has been on a small dose of lorazepam for anxiety for five years may not realize that this medication is a significant contributor to their increasing forgetfulness and difficulty concentrating.

The danger with benzodiazepines is that people often develop tolerance, meaning they need higher doses to feel the same effect—which amplifies the cognitive impact. Additionally, when benzodiazepines are combined with opioids or other sedating drugs, the risk of severe confusion, oversedation, and even respiratory depression multiplies. Guidelines from major medical organizations, including the Beers Criteria (which flags potentially inappropriate medications for older adults), strongly recommend avoiding benzodiazepines in this population. Yet abrupt discontinuation is also risky, requiring careful tapering under medical supervision to prevent rebound anxiety or seizures.

Opioid Painkillers and Cognitive Side Effects

Opioid medications like oxycodone, hydrocodone, and morphine are powerful painkillers, but they also suppress central nervous system activity and can cause significant confusion, drowsiness, and impaired thinking. Older adults are particularly vulnerable to opioid-related cognitive problems because their bodies metabolize these drugs more slowly. An older person prescribed oxycodone for chronic back pain may experience confusion or hallucinations at doses that would be considered standard, because their kidneys and liver don’t clear the drug as efficiently as a younger person’s would.

Opioid confusion is especially dangerous because it can be subtle and gradual, causing a person to seem “off” or confused without an obvious trigger. Unlike a sudden fall or visible side effect, cognitive decline might be attributed to aging or dementia rather than the medication. When opioids are combined with other drugs that affect the brain—such as sedating antidepressants, anticholinergics, or benzodiazepines—the cognitive and safety risks increase substantially. This is a key reason why pain management guidelines now recommend using the lowest effective opioid dose for the shortest duration possible, and exploring non-medication alternatives first.

Recognizing Medication-Induced Confusion vs. Dementia

Distinguishing between confusion caused by medication and confusion caused by dementia can be challenging, but there are important clues. Medication-induced cognitive problems typically appear relatively suddenly after starting a new drug or increasing a dose, whereas dementia develops gradually over months or years. If an older adult’s thinking suddenly becomes foggy after beginning a new blood pressure medication or antibiotic, the medication is likely the culprit. If the same person has been experiencing slow, steady memory decline for two years, dementia is more probable—though medications could still be making it worse.

A practical approach is to keep a symptom diary that notes when confusion started, what medications were added or changed around that time, and how the confusion progresses. This information is invaluable when discussing the problem with a doctor. Some confusion may improve within days or weeks of stopping a problematic medication, while dementia-related confusion does not. A comparison: a person who becomes acutely confused two days after starting a high-dose antihistamine and improves within a week of stopping it almost certainly had medication-induced delirium, not progressive dementia. Time and attention to the timeline are key diagnostic tools.

Polypharmacy: When Multiple Medications Create Compounding Risk

Polypharmacy—taking five or more medications regularly—is extremely common in older adults and dramatically increases the risk of medication interactions and adverse effects, including confusion. Each additional medication increases the chance of a harmful drug-drug interaction or a compounding side effect. An older adult taking a statin for cholesterol, a diuretic for blood pressure, a calcium channel blocker for the heart, an anticholinergic for overactive bladder, and an over-the-counter sleep aid might not realize that this combination creates a substantially higher risk of confusion and cognitive impairment than any single drug would.

The limitation of polypharmacy risk is that it’s difficult to predict exactly which combination will cause problems in a given person; individual factors like age, kidney function, liver function, and genetic variation in drug metabolism all matter. A medication interaction that causes significant confusion in one person might cause none in another. This unpredictability is why regular medication reviews with a pharmacist or physician who has access to the complete medication list are essential. Some healthcare systems now use computerized tools to screen for potentially problematic drug combinations, but many do not, placing the burden on patients and caregivers to advocate for safety checks.

Anticholinergic Burden Scales and Clinical Assessment

Researchers have developed anticholinergic burden scales to help quantify how many medications a person is taking that have anticholinergic properties, because the total burden—not just individual medications—drives cognitive risk. The Anticholinergic Cognitive Burden (ACB) scale assigns each medication a score, and cumulative scores correlate with cognitive impairment risk. A person taking three medications with modest anticholinergic properties might accumulate an ACB score that predicts meaningful cognitive side effects.

Unfortunately, most patients and many physicians are not familiar with these scales, and they are not routinely used in primary care settings. Some pharmacies and healthcare organizations have begun offering medication therapy management services that include anticholinergic burden assessment, but access to these services varies widely. If available, requesting an anticholinergic burden review from a pharmacist can be eye-opening—patients are often surprised to learn how many of their medications contribute to this effect. An example: a person taking amitriptyline (an antidepressant), diphenhydramine occasionally for sleep, tolterodine (for bladder control), and paroxetine (for anxiety) might accumulate a significant anticholinergic burden without realizing it, because each medication is being prescribed by a different doctor for a different reason.

Managing Medications Safely When Confusion Is a Concern

If someone is experiencing confusion and medications are suspected, the next step is not to stop all drugs abruptly—which can be dangerous—but to schedule an appointment with their primary care doctor or pharmacist to review the entire medication list. Bring a complete list including over-the-counter drugs, supplements, and even occasional medications. Many cognitive problems can be resolved by switching to an alternative medication with lower anticholinergic burden, reducing a dose, or eliminating a medication that is no longer necessary. For example, switching from amitriptyline to a non-anticholinergic antidepressant like sertraline, or from a first-generation antihistamine to a non-sedating one, can eliminate medication-induced confusion while treating the underlying condition just as well.

Medication adjustments should be made gradually and under medical supervision, especially when discontinuing benzodiazepines or other drugs with withdrawal risks. A healthcare provider can help prioritize which medications are essential and which can be eliminated or changed. Regular follow-up appointments to assess whether cognitive symptoms improve after medication changes are important, because sometimes confusion persists due to other causes and a different intervention is needed. Keeping detailed records of what medications were changed, when, and how the person’s cognition responded helps guide future medication decisions and ensures that the person’s full medical history is always visible to their care team.