Neurological Side Effects: What Medications Can Do to Your Nerves and Brain

When you take a pill for inflammation, high blood pressure, or dementia, you might not think about your neurological side effects, changes in brain or nerve function caused by medications. Also known as central nervous system reactions, these can range from mild dizziness to serious confusion or tremors. It’s not rare — and it’s not always listed upfront on the label.

Some drugs directly affect how your nerves send signals. For example, dexamethasone, a powerful steroid used for swelling and allergies can cause mood swings, insomnia, or even seizures in high doses. rivastigmine, a medication for Alzheimer’s that boosts brain chemicals often leads to dizziness, headaches, or muscle twitching. Even something as common as atenolol, a beta-blocker for blood pressure can make you feel off-balance or foggy-headed. And promethazine, an antihistamine used for nausea and allergies? It’s notorious for causing drowsiness so strong it feels like a blackout.

These aren’t random side effects — they’re predictable patterns. The brain is sensitive. If a drug crosses the blood-brain barrier, it can mess with neurotransmitters, slow nerve signals, or overstimulate certain areas. That’s why you’ll see neurological side effects show up across very different meds: steroids, Alzheimer’s drugs, heart pills, antihistamines, even antibiotics. The common thread? They all touch your nervous system in some way.

You don’t need to panic. Most of these effects are temporary, dose-dependent, or manageable. But knowing what to watch for — like sudden memory lapses, unexplained tremors, or trouble walking — can help you catch problems early. The posts below dig into real cases, patient reports, and doctor insights on exactly which drugs are most likely to cause these issues, how they compare to alternatives, and what steps you can take to stay safe without giving up your treatment.