The People's Perspective on Medicine

Gabapentin and Fuzzy Thinking: A Recognized Side Effect

Fuzzy thinking is not an official FDA side effect of gabapentin or pregabalin. And yet we keep hearing from people who complain about this complication.
Pain, neuropathic pain,

We have been writing a lot about GABA drugs like gabapentin (Neurontin) and pregabalin (Lyrica). That because a report from ISMP (Institute for Safe Medication Practices) has a QuarterWatch article: “Focus on Three Psychoactive Drugs” (March 27, 2019).  A lot of people love these GABA “analogs.” They tell us that these are the only medicines that ease their nerve pain. But others report brain fog or fuzzy thinking. That can be a challenging complication. Here is just one example of such a side effect.

Fuzzy Thinking While Taking Gabapentin:

Q. I took GABA drugs, both gabapentin and pregabalin for severe back pain. After some months I had very foggy thinking. I couldn’t remember simple things. I was sleepy all the time. I had a much slower rate of processing information. I even ran off the road in my car a couple of times, something I never did before.

When I asked my doctor about it he said:

“Oh yeah, that’s a known side effect. We don’t mention it because not everyone has it.”

I stopped the meds right away, knowing there would be hell to pay, and there was. At least I was prepared for withdrawal symptoms. My husband was very supportive and understanding during this time. He was also glad I was off the meds because he said he did not recognize the person I had become. I have since found relief through chiropractic care. Not 100 percent but pain free most days. When I have pain, it’s much less severe.

A. A report from ISMP QuarterWatch (March 27, 2019) warns about the inappropriate use of GABA drugs like gabapentin and pregabalin. Mental impairment, confusion and memory loss are recognized side effects. Some people use the term fuzzy thinking to describe the brain impact.

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Sleepiness and dizziness are quite common complications of both drugs. Your doctor should have warned you about the dangers of driving while taking either medicine.

Gabapenin & Pregabalin Brain Side Effects Include:

  • Memory Loss
  • Amnesia
  • Memory Impairment
  • Confusion (fuzzy thinking)
  • Somnolence (sleepiness)
  • Dizziness
  • Disorientation (brain fog, fuzzy thinking)
  • Abnormal Thinking
  • Depression

How to Avoid Adverse Drug Reactions:

In our book, Top Screwups Doctors Make and How to Avoid Them, we include tips to avoid adverse reactions and a drug safety questionnaire that you can copy and have your doctor fill out. You will be better informed next time you get a new prescription. The book is available at

Share y0ur own experience with GABA drugs in the comment section below.

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    About the Author
    Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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    I am a 70 year old male and was prescribed this ‘Devil Capsule’ for anxiety by my GP. I have tapered down from 300 mg 3X a day to 100 mg twice a day. Even at this low dose, I am going through HORROR! Constant brain fog, confusion and inability to navigate. I have lost all interest in appearance or anything else that I care about. The GI distress is a whole story unto itself. All that I do is lie in bed like a vegetable. I HATE this drug and want it out of my life. Yes, I am tapering but, not too quickly. I tried a more aggressive taper about a month ago. It was a horrible experience. My heart goes out to anyone that has experienced this drug. I sincerely feel your pain.

    Hopefully, this drug will be will be removed. Thank you for listening.

    I have been prescribed Gabapentin to use for nerve pain associated from a Traumatic Cauda Equina injury 33 years ago and numerous surgeries.Initially prescribed Elavil that put 33 pounds on me in 3 months,Pain Management Physician took me off it and it was decided Gabapentin was best course of treatment.Now I feel like I am floating,cannot verbalize thoughts constructively ,I sit down and fall asleep.In conversation my thoughts wonder,I am very appreciative someone who knows me brought this to my attention and confirmed its obvious.This is a terrible experience yet the surgeons say they can repair problem yet cannot guarantee I’d be able to walk or have body functions.It was 33 years ago I lost those and over time got body functions somewhat controlled but walk in leg brace barely lifting my foot in my gait. I am totally baffled here ,I will see pain management Physician in seven day.

    I was taking Lyrica for 6-7 years and the many side effects were horrible. The memory loss and loss of balance was very scary. I’ve been taking Cymbalta for 10+ years and it has the same side effects. I slowly tapered completely off Lyrica first and I’m slowly tapering off Cymbalta now. I’m down from 60 mg to 1.2 mg and every side effect is gone. Even the memory loss, brain fog and loss of balance is gone. I tapered off both by 10% of my last dosage taken every 2 weeks. For my last 10 beads I’ve been tapering by 1 bead every 3 weeks. I have had minimal and manageable withdrawals. There are groups on Facebook for each of these medications which have support, good advice and great information. We are like family and we get each other through every day. I wish everyone the best. Take care x

    Years ago I had an abrupt lumbar plexopathy, dramatically altered gait, impaired movement, and intense muscle pain on any movement. I was placed on neurontin 300mg. Almost immediately I had trouble with brain fog, sleepiness, decreased ability to get words out, and crushing depression. Went through lyrica, Cymbalta, and another name I don’t remember. While time of onset varied a bit, the end result was markedly similar. And none of them ever did much for the pain levels I was in. The neurologist would tell me to just stop the med in question and I was not advised that the rebound could be brutal. I have lived with levels of that pain and diminished mobility ever since those days. My muscles still cramp and seize. My nerves still have pain, tingles, numbness, sharp “lightening strikes” at random intervals. Eventually I was placed on disability, as severity of symptoms is not predictable. The depression has never lifted since those meds. It lessons somewhat, but is not gone and is now a constant life battle. I would never let anyone I know go on any of those meds without starting at the lowest possible dose, working up from there, and constant vigilance in monitoring behavior and cognitive reactions. At the first signs, withdraw slowly. Never go to another drug in that family. I am delighted to hear there are some who got help from these drugs. I would never go there again. I think extreme caution in using them is essential.

    My experiences with “Gabby” have been over the last 5 years. It was prescribed for cronic pain due to spinal nerve damage. 900mgs a day.
    At first, it seemed like a miracle. Then, over time, the brain fog and memory loss increased as cognitive skills decreased.
    The real scare was when I tried to STOP taking it. My body shook with tremors.
    With titrating down more slowly, the tremors lessened. Sorry to say I’ve never been able to drop Gabby/Neurontin entirely. Any lower than 100 mg 2X a day will bring on the tremors and/or migraines auras.
    Dr’s opinion….”Your body must need it then” Spinal pain is back. I feel trapped.

    Do these side effects dissipate after discontinuing the drug? The mental confusion , memory loss and poor balance can be dangerous. What can we do to hasten the return to normal functioning?

    I am currently taking gabapentin 300mg/day. I am noticing the brain fog as well, but I am also experiencing GI symptoms- nausea, vomiting, diarrhea…I would like to wean off the drug. This low dose is ineffective, but higher doses cause more GI distress. I could use some suggestions for how to taper dose for least amount of side effects.

    I have had severe episodes of neuropathy pain for the last ten years. The major cause of these episodes has been too much sugar in my diet. Although I was told about gabapentin last November by my primary care doc, I requested an opiate to make the pain tolerable.
    Since, I have careful about sugar and I have had one episode of neuropathy pain since.

    I was informed by my podiatrist that once gabapentin is started it cannot be stopped. For me medication is a very poor substitute for living a quality life.

    I have peripheral neuropathy as a result of Chemo treatments for breast cancer and I too, have experienced fuzzy thinking from taking Gabapentin. I often search for words, can’t concentrate and stay tired much of the time. I have been concerned that I was developing dementia or Alzheimer’s. I am relieved to know that I am not alone with this side effect. The relief I receive for the nerve damage is part of the trade off.

    I have been taking 300mg for 1 yr. for small fiber neuropathy. I was originally prescribed 100 mg to be taken 2/day and 200mg at bed time but cut back to 300mg at night because of side effects. With this low dose I still experience day sleepiness and short term memory loss. For people with neuropathy I don’t know of anything else which helps the nerve pain unlike people with other types of pain. It seems we have no other option but to live with the pain or side effects.

    I started taking Gabapentin for insomnia. After 6 weeks, my sister pointed out to me that I was abnormally depressed and that it had been getting worse. I quit the drug and my moods went back to normal. Not for me! I was not warned about possible mood side effects by my doctor, a neurologist specializing in sleep disorders.

    I am on 900 mg of gabapentin and have none of these side effects. It helps me a lot with the pain and numbness in my feet. I can see that not everyone gets this.

    Doctors don’t want to ‘mention’ side effects because they don’t want to say bad things about the drugs they prescribe. That would be bad for ‘business’.

    I took gabapentin while recovering from 2 herniated disks to reieve pain. I was given a stepped doseage, up at the beginning, then tapering off. It definitely caused some drowsiness, and I found my thought process was definitely slowed a bit, sometimes causing inability to recall names, etc. It definitely did help though.

    I have degenerative disc disease. Had my neck fused in 2015. In 2016 I started taking 900 mg of Gabapentin at night for what I call “zingers” , like the feeling you get when you hit your funny bone in your elbow. I have zingers in my face now which is new , usually happens when I wake up and then I take another 300 mg and it subsides.
    Once I ran out of Gabapentin and didn’t take the night before. Oh my, this was horrible. I woke up and everything in my body was zinging, every step I took zinged. I filled RX and took immediately and I was fine. So it does help.
    After reading the article about feeling foggy and searching for words I have this and didn’t relate to taking Gabapentin. My question is does this feeling of being foggy diminish after stopping the Gabapentin and more importantly how about your memory? Please, I need feedback!

    Neurologists know confusion and the inability to finish a thought process is a side effect of gabapentin/pregabalin. I don’t know why they haven’t reported it to the FDA, or if they have but the FDA has chosen to ignore it.

    My friend was taking gabapentin for a short time and began to have problems. We went to a neurologist and he asked what drugs my friend was taking. When we mentioned gabapentin, the doctor immediately recognized where the problem was coming from. My friend stopped taking gabapentin and his abilities returned to normal.

    I can say that gabapentin gave me extreme brain fog and confusion. I became unable to cook because I would wander off with food cooking and burn the pan so badly I would have to rush it outside til the smoke cleared. I began to fear I would burn my house down!

    Many years ago I was on Lyrica (oregabalin) and experienced no brain fuzz. I was instantly rid of my neuropathic pain. However, I developed a rash. Not recognizing it as a drug reaction I kept taking the med. The rash kept getting worse, so I was forced to stop it.

    Last year I started Gapapentin, working up from a low dose to a medium dose. It did help with the neuropathy, but, I definitely had some brain fuzz. I had some memory loss, and really scrambled for words. But, I have continued to take it for fear the neuropathy would return and my movements would be limited again.

    I don’t believe it’s really bad that everyone notices, or worries at least. Mostly it’s attributed to age (isn’t everything?)

    I’ve been on gabapenin about five years now. At one point my Dr.had me on 2400 mg daily. What a nightmare. Although it did help with my nerve damage, the side effects were terrible, fuzzy thinking. I couldn’t communicate without stuttering. I knew what I wanted to say but it was a mess. I did some research and read where that is a possible side effect.I stopped taking the med and the withdrawal was terrible, then the nerve pain came back in full force.I am now on 600 mg.and the stuttering has stop but still slower in my thought & speech.

    Gabapentin seems to be a go-to drug for older people with any kind of pain, especially arthriric. I was given a dosage much less than the other women I know, and after one pill I was extremely disoriented, sleepy, had brain fog and was unbalanced. Enough so that I was afraid to go out. I now list it as a drug I am allergic to. And it made no difference to my joint pain or leg cramps. It is disturbing that so many older people I know are prescribed Gabapentin for a whole range of unrelated problems.

    Several years ago, I was prescribed gabapentin for peripheral neuropathy. It seemed ineffective, so I slowly tapered it off….apparently not slowly enough. For years I have had periodic “migraine episodes” (the flashing lights , but without the pain). These are not debilitating, just annoying, and these occur very infrequently…maybe two or three a year. However, after tapering off the gabapentin, the episodes increased dramatically. After my last dose of gabapentin, I had ten migraine episodes in one day. Thankfully they stopped, but it was quite frightening.

    This article was of interest to me since I have taken 600 mg of gabapentin per day for almost three years. One important piece of information was missing from the question and the reply: how many mg per day was the person taking, and what minimum dosage has been observed to produce the “fuzzy thinking” side effect? I have noticed this occurring to me so it may be that a very low dose can cause this effect.

    Gabapentin gave me some awful cramps. They were in my chest and back. They hurt like no other cramp I have ever had.

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