7 Common Medications That May Affect Memory and Brain Health

Forgetting a name, misplacing your keys, or struggling to remember why you walked into a room can happen to anyone. Occasional forgetfulness is often normal, particularly during periods of stress, poor sleep, or distraction.

However, some people notice changes in memory or thinking after starting a new medication or increasing the dose of an existing one. Certain medicines can cause side effects such as confusion, drowsiness, difficulty concentrating, slowed thinking, or short-term memory problems. These effects can be especially noticeable in older adults because the body may process medications differently with age.

This doesn’t mean these medications are necessarily dangerous or that you should stop taking them. Many are important and effective treatments for serious health conditions. The key is understanding their potential effects and talking with a healthcare professional if you notice unexplained changes in memory or thinking.

Here are seven common medication categories that may affect memory and brain function in some people.

1. Antihistamines

Antihistamines are commonly used to relieve allergy symptoms such as sneezing, itching, runny noses, and watery eyes. Some are also used as sleep aids or to treat motion sickness.

Older antihistamines, sometimes called first-generation antihistamines, can have anticholinergic effects. These medicines can interfere with a chemical messenger called acetylcholine, which plays an important role in memory, attention, and other brain functions.

Examples include diphenhydramine and some other older allergy medications.

For some people, these medicines can cause drowsiness, confusion, difficulty concentrating, or problems with short-term memory. The effects may be more noticeable in older adults.

The American Geriatrics Society specifically identifies several first-generation antihistamines as medications with strong anticholinergic properties that may be problematic for older adults.

What should you do?

If you regularly use an over-the-counter allergy or nighttime medication and have noticed increasing grogginess or memory problems, talk with a pharmacist or doctor.

Don’t automatically stop a prescribed medication. Instead, ask whether another treatment with fewer cognitive side effects might be appropriate.

2. Benzodiazepines

Benzodiazepines are medications commonly prescribed for anxiety, panic disorders, certain seizure conditions, and sometimes insomnia.

Examples include medications such as diazepam, lorazepam, alprazolam, and clonazepam.

These drugs work by slowing activity in the central nervous system. While this can help reduce anxiety and promote relaxation, it can also cause sleepiness, slowed reactions, impaired coordination, and difficulty concentrating.

Some people may also experience memory problems while taking these medications.

The risk can be particularly important for older adults. Increased sensitivity to sedating medications can contribute to confusion, balance problems, and falls.

Long-term use can also lead to physical dependence, meaning the medication should not generally be stopped suddenly without medical guidance.

A safer approach

If you’ve been taking a benzodiazepine regularly and are concerned about memory, speak with your healthcare professional.

A doctor may determine that you still need the medication, adjust the dose, change the treatment plan, or gradually reduce the medication when appropriate.

Never abruptly stop a regularly used benzodiazepine without professional guidance.

3. Sleeping Pills

Medications prescribed or used for insomnia can also affect alertness and cognitive function.

Some sleep medicines can cause next-day drowsiness, slowed reaction times, confusion, or problems with attention. These effects may be particularly noticeable in older adults.

Common prescription sleep medications include drugs sometimes referred to as “Z-drugs,” such as zolpidem, zaleplon, and eszopiclone.

Although these medicines can help some people sleep, they aren’t always the best long-term solution for chronic insomnia.

Poor sleep itself can also affect memory, concentration, mood, and mental performance. This creates an important distinction: if someone has memory problems while taking a sleep medication, the medication may contribute, but inadequate sleep can also be part of the problem.

Improving sleep without relying entirely on medication

Good sleep habits can make a meaningful difference.

Try maintaining a consistent bedtime, reducing bright screens before bed, keeping the bedroom comfortable and quiet, and limiting caffeine late in the day.

For persistent insomnia, ask a healthcare professional about evidence-based treatments for chronic sleep problems.

4. Certain Antidepressants

Antidepressants are widely used to treat depression, anxiety disorders, and several other conditions.

Not all antidepressants affect memory in the same way. However, some older antidepressants have stronger anticholinergic properties and can cause side effects such as dry mouth, constipation, drowsiness, confusion, and difficulty concentrating.

Tricyclic antidepressants are one example.

Some antidepressants can also cause sleepiness, while others may affect sleep or alertness differently. The response varies considerably from person to person.

It’s important not to assume that experiencing forgetfulness while taking an antidepressant means the medication is damaging your brain. Depression and anxiety themselves can significantly affect concentration and memory.

Talk to your doctor before making changes

If you notice cognitive changes after starting an antidepressant, tell your healthcare provider.

The medication may be adjusted, replaced, or continued depending on your symptoms and medical history. Stopping an antidepressant suddenly can cause unwanted withdrawal symptoms or a return of the condition being treated.

5. Certain Bladder-Control Medications

Medications used to treat an overactive bladder or urinary urgency can sometimes have anticholinergic effects.

Examples include certain medications in the antimuscarinic class, such as oxybutynin and related drugs.

These medications work partly by reducing unwanted bladder contractions. However, medications with anticholinergic effects can also influence neurotransmitters involved in brain function.

For some people, this can result in confusion, drowsiness, or difficulty thinking clearly.

Older adults may be particularly sensitive to these effects.

This doesn’t mean people with bladder problems should simply stop treatment. Urinary symptoms can significantly affect quality of life, and effective treatments are available.

Ask about your options

If you’ve been taking a bladder-control medication and have noticed new memory or concentration problems, discuss the issue with your doctor.

Depending on your circumstances, there may be different medications or non-drug approaches worth considering.

6. Some Muscle Relaxants

Muscle relaxants are commonly prescribed for painful muscle spasms, injuries, and certain musculoskeletal conditions.

Examples include cyclobenzaprine and other centrally acting muscle relaxants.

Because these medications can affect the central nervous system, they may cause drowsiness, dizziness, reduced alertness, and difficulty concentrating.

For older adults, these effects can also increase the risk of falls.

Some muscle relaxants have anticholinergic properties as well, adding another potential pathway through which they may contribute to confusion or cognitive problems.

Use with caution

If you’re taking a muscle relaxant, be careful about driving or performing activities that require alertness until you know how the medication affects you.

Combining these medicines with alcohol or other sedating medications can increase unwanted effects.

If you regularly need a muscle relaxant, ask your healthcare provider whether the medication is still necessary and whether there are other approaches that could help.

7. Some Antipsychotic Medications

Antipsychotic medications are powerful prescription drugs used for conditions such as schizophrenia, bipolar disorder, and certain severe behavioral symptoms.

They can be highly beneficial when appropriately prescribed, but they can also have significant side effects.

In older adults with dementia, antipsychotic medications require particular caution. Some are associated with an increased risk of stroke and greater rates of cognitive decline and mortality in people with dementia.

That doesn’t mean these medications should never be used. In certain serious psychiatric conditions, they can be essential.

The important issue is appropriate prescribing, careful monitoring, and regular review of whether the benefits continue to outweigh the risks.

Never stop these medications suddenly

If you or a family member takes an antipsychotic medication, don’t stop it without speaking with the prescribing clinician.

A healthcare professional can determine whether the medication remains appropriate and whether the dosage or treatment strategy should be changed.

Why Older Adults May Be More Sensitive

Age can change the way the body absorbs, processes, and eliminates medications.

Older adults are also more likely to take several medications at the same time. This is known as polypharmacy.

Taking multiple medicines can increase the possibility of drug interactions and side effects. Several medications may also have similar effects on the brain, such as sedation or anticholinergic activity.

This is one reason medication reviews can be especially valuable for older adults.

A doctor or pharmacist can examine all prescription drugs, over-the-counter products, supplements, and herbal products being taken and look for possible interactions.

Anticholinergic Medications Deserve Special Attention

One of the most important concepts when discussing medication-related memory problems is the term anticholinergic.

Anticholinergic medications interfere with acetylcholine, a neurotransmitter involved in several functions, including memory, learning, attention, and muscle activity.

Many different types of medication can have anticholinergic properties.

Some antihistamines, antidepressants, bladder medications, muscle relaxants, and other drugs may fall into this category.

The effect can become more significant when someone takes multiple medications with anticholinergic properties at the same time.

For older adults, healthcare professionals often try to minimize unnecessary exposure to medications with strong anticholinergic effects.

Medication Isn’t Always the Cause of Memory Problems

It’s important not to blame every memory problem on medication.

Many other factors can affect memory and concentration.

These include:

• Poor sleep
• Stress and anxiety
• Depression
• Dehydration
• Nutritional deficiencies
• Thyroid problems
• Infections
• Alcohol use
• Other medications or drug interactions
• Certain neurological conditions
• Changes in hearing or vision

A sudden change in mental status can sometimes signal a medical problem that needs prompt attention.

That’s why new or worsening confusion should not simply be dismissed as normal aging.

What to Do If You Notice Memory Changes

If you’ve recently developed forgetfulness, confusion, unusual sleepiness, or difficulty concentrating, make a list of everything you’re taking.

Include prescription medications, over-the-counter products, vitamins, supplements, and herbal remedies.

Write down when the symptoms started and whether they appeared after starting or changing a medication.

Then discuss the situation with your doctor or pharmacist.

A healthcare professional can determine whether a medication may be contributing to the problem and whether another explanation should be investigated.

Most importantly, don’t stop prescription medication on your own.

Some medications need to be reduced gradually, and suddenly stopping certain drugs can cause serious withdrawal symptoms or allow the underlying condition to return.

The Bottom Line

Several commonly used medications can potentially affect memory, concentration, alertness, or overall brain function in certain people.

Antihistamines, benzodiazepines, sleep medications, some antidepressants, bladder-control drugs, muscle relaxants, and certain antipsychotics deserve particular attention—especially among older adults.

However, this doesn’t mean these medications are inherently bad or that everyone who takes them will experience memory problems. Many are important treatments that can significantly improve quality of life.

The safest approach is to stay informed, review medications regularly, and tell your healthcare professional about any new changes in memory or thinking.

If you take several medications, a periodic medication review can be particularly useful. Sometimes a dosage adjustment, medication change, or removal of an unnecessary drug can reduce side effects while maintaining effective treatment.

Your brain health depends on much more than medication. Good sleep, regular physical activity, a balanced diet, social engagement, management of chronic health conditions, and appropriate medical care all play important roles in maintaining cognitive health as you age.