What Is “Medication Fog?”

Sometimes a medication you’re taking can cause you to experience brain fog. You might feel like you can’t think straight. Or you may have trouble remembering things and wonder whether you’re developing dementia or other mental health issues.

This type of brain fog is also called “medication fog.” And it can often leave you feeling scared or worried.

You’re not alone if you have brain fog from medications you take. Medication fog is a common side effect of numerous medications.

The good news is depending on the medication you take, medication fog often goes away once you stop taking the medication.

But don’t stop taking your medications without talking with your doctor first. You may need to take these medications for serious health conditions. And suddenly stopping your medications can put you at risk for other side effects and can worsen symptoms of the condition the medications treat.

Here’s how to tell if you may have medication fog.

What Is Brain Fog?

Brain fog isn’t a medical condition. And there’s no exact definition or specific diagnosis. It’s a general term used to describe symptoms related to cognitive functioning — your ability to think and process information.

When someone has brain fog, they may say their brain feels “fuzzy” or “foggy” or they have “cloudy” thinking.

Symptoms of medication fog

How long symptoms of medication fog last depends on the medication involved. Symptoms of medication brain fog can last while you take the medication. Or you may continue to feel symptoms weeks or months after you stop taking the medication.

Your brain fog symptoms can differ from someone else’s. Common symptoms include:

  • Feeling confused or disoriented.
  • Forgetfulness or trouble remembering.
  • Difficulty concentrating, focusing, or thinking.
  • Trouble following directions or performing complex tasks.
  • Problems with planning and organizing.
  • Difficulty with processing language, such as understanding what others are saying or finding the right words to use.

You may have medication fog if you notice one or more of the above symptoms after:

  • You start taking a new medication.
  • Your doctor increases your dose of a medication you already take.

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What Medications Can Cause Brain Fog

Not all medications cause brain fog, and how you react to a medication differs from someone else’s reaction. But certain medications can increase your risk of brain fog. Common medications linked to brain fog and cognitive problems include:


These drugs are used to treat an overactive bladder and reduce the sudden urge to urinate. They include:

  • Darifenacin (Enablex).
  • Oxybutynin (Ditropan XL, Gelnique, Oxytrol).
  • Solifenacin (Vesicare).
  • Tolterodine (Detrol).
  • Trospium (Sanctura).


These drugs are often used to prevent seizures. Doctors may also prescribe these to treat nerve pain, bipolar disorder, mood disorders, and mania. They include:

  • Acetazolamide (Diamox).
  • Carbamazepine (Tegretol).
  • Ezogabine (Potiga).
  • Gabapentin (Neurontin).
  • Lamotrigine (Lamictal).
  • Levetiracetam (Keppra).
  • Oxcarbazepine (Trileptal).
  • Pregabalin (Lyrica).
  • Rufinamide (Banzel).
  • Topiramate (Topamax).
  • Valproic acid (Depakote).
  • Zonisamide (Zonegran).


These drugs are often used to treat anxiety disorders or help with sleep problems, like insomnia. Doctors may also prescribe these to treat muscle spasms and prevent seizures. They include:

  • Alprazolam (Xanax).
  • Chlordiazepoxide (Librium).
  • Clonazepam (Klonopin).
  • Diazepam (Valium).
  • Flurazepam (Dalmane).
  • Lorazepam (Ativan).
  • Midazolam (Versed).
  • Quazepam (Doral).
  • Temazepam (Restoril).
  • Triazolam (Halcion).


These drugs are often used to treat high blood pressure, congestive heart failure, and abnormal heart rhythm. Doctors may also prescribe these for migraine, tremors, chest pain known as angina, and certain types of glaucoma. Common ones include:

  • Atenolol (Tenormin).
  • Carvedilol (Coreg).
  • Metropolol (Lopressor, Toprol).
  • Propranolol (Inderal).
  • Sotalol (Betapace).
  • Timolol (Timoptic).

Chemotherapy drugs

Numerous drugs used to treat cancer can contribute to brain fog, known as “chemo brain.” People undergoing cancer treatment may also get antihistamines or corticosteroids to reduce their risk of chemo side effects, such as nausea. These drugs can add to the risk of “chemo brain.”

Common chemotherapy drugs that can cause brain fog include:

  • 5-fluorouracil.
  • Cyclophosphamide.
  • Doxorubicin.
  • Methotrexate.
  • Platinum-based agents, including cisplatin and carboplatin.
  • Taxanes, including docetaxel and paclitaxel.


These drugs are used to reduce pain, inflammation, and swelling. Doctors may also prescribe these to treat allergic reactions, rashes, acne, or asthma. Common ones include:

  • Prednisone (Deltasone).
  • Cortisone Acetate (Cortone).
  • Methylprednisolone (Medrol).

Dopamine agonists

These drugs are used to treat Parkinson’s disease, certain pituitary tumors, and restless legs syndrome (RLS). They include:

  • Apomorphine (Apokyn).
  • Pramipexole (Mirapex).
  • Ropinirole (Requip).

First-generation antihistamines

These drugs are used to relieve or prevent allergy symptoms. They are also used to treat the common cold or prevent motion sickness, nausea, vomiting, dizziness, anxiety, or insomnia. They include:

  • Brompheniramine (Dimetane).
  • Carbinoxamine (Clistin).
  • Chlorpheniramine (Chlor-Trimeton).
  • Clemastine (Tavist).
  • Diphenhydramine (Benadryl).
  • Hydroxyzine (Vistaril).

Nonbenzodiazepine sedative-hypnotics

These drugs are used to treat sleep problems, such as insomnia, and mild anxiety. They include:

  • Eszopiclone (Lunesta).
  • Zaleplon (Sonata).
  • Zolpidem (Ambien).

Opioid pain medications

Opioids are used to treat moderate or severe pain. They include:

  • Fentanyl (Duragesic).
  • Hydrocodone (Norco, Vicodin).
  • Hydromorphone (Dilaudid, Exalgo).
  • Morphine (Astramorph, Avinza).
  • Oxycodone (OxyContin, Percocet).


These drugs are used to help lower cholesterol. They include:

  • Atorvastatin (Lipitor).
  • Fluvastatin (Lescol).
  • Lovastatin (Mevacor).
  • Pravastatin (Pravachol).
  • Rosuvastatin (Crestor).
  • Simvastatin (Zocor).

Tricyclic antidepressants (TCAs)

TCAs are often used to treat depression and anxiety disorders. Doctors may also prescribe these for eating disorders, obsessive-compulsive disorder, chronic pain, smoking cessation, severe menstrual cramps and hot flashes caused by menopause. They include:

  • Amitriptyline (Elavil).
  • Clomipramine (Anafranil).
  • Desipramine (Norpramin).
  • Doxepin (Sinequan).
  • Imipramine (Tofranil).
  • Nortriptyline (Pamelor).
  • Protriptyline (Vivactil).
  • Trimipramine (Surmontil).

What Else Causes or Contributes to Brain Fog?

Inflammation in the brain is another main cause of brain fog. Injury to your brain or certain health conditions can cause brain inflammation. Other changes in the brain, such as hormonal and chemical changes, can also cause brain fog.

Dozens of physical and mental health conditions are linked to brain fog. Other health conditions that may cause or contribute to brain fog include:

  • Allergies.
  • Attention deficit hyperactivity disorder (ADHD).
  • Chronic fatigue syndrome or fibromyalgia.
  • Chronic stress.
  • Concussion.
  • COVID-19 infection.
  • Kidney failure.
  • Lupus.
  • Lyme disease.
  • Migraine.
  • Mood disorders, such as anxiety and depression.
  • Multiple sclerosis.
  • Perimenopause and menopause.
  • Rheumatoid arthritis (RA).
  • Sleep disorders, including insomnia and sleep apnea.

Self-Care Tips for Medication Fog

If you have medication fog, it’s important to reduce your risk of added brain fog caused by poor lifestyle choices. Instead, make sure you follow these lifestyle changes:

  • Get enough quality sleep.
  • Eat regular, healthy meals.
  • Get regular physical activity.
  • Reduce stress.

It sounds simple but doing these things can help reduce inflammation in your body that contributes to brain fog.

When Should You Talk to Your Doctor About Medication Brain Fog?

Even though medication fog is common you don’t have to suffer in silence. You should see your doctor if:

  • Lifestyle changes don’t help.
  • Brain fog is affecting activities of daily living.
  • Symptoms of medication fog get suddenly or significantly worse.
  • You develop new or sudden brain fog symptoms.
  • You have symptoms of other medical conditions that cause brain fog.

You doctor can make sure your symptoms are related to your medications, and not something else. They may run blood and imaging tests. To rule out dementia, they may test your ability to recall information or follow a set of directions.

In dementia, symptoms and cognitive function get worse over time. With medication brain fog, you may feel your symptoms more on some days and less on others. But your cognitive function doesn’t get worse over time.

If your brain fog is medication-related, your doctor may change the medication or the dosage or amount you take. If you still need to take a medication that causes brain fog, your doctor can recommend ways to help you manage those side effects. These can include occupational therapy and stress-reduction techniques.

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"Is It Something I'm Taking?" Medications That Can Mimic Dementia. BrightFocus Foundation. Link.

Kayt Sukel. Lifting the Fog. June 2022. New Scientist. Link.

Lupus and Brain Fog. Lupus Foundation of America. Link.

RA's Effect on the Brain. Arthritis Foundation. Link.

Dr. Armon Neel, Jr. Caution! These 10 Drugs Can Cause Memory Loss. AARP. Link.

An Overview on Chemotherapy-induced Cognitive Impairment and Potential Role of Antidepressants. Sept. 2020. Current Neuropharmacology. Link.

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