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.

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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  1. Mitzimaus

    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.

  2. Helen

    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.

  3. Lisa

    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.

  4. Diane

    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.

  5. Don

    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’.

  6. Kirk
    St. Paul

    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.

  7. Nancy

    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!

  8. Jeanette H.
    15008 Cypress Hills Dr, Dallas 75248

    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.

  9. Brenda

    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!

  10. Kerry

    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?)

  11. Ken

    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.

  12. Jacqueline H.

    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.

  13. Hilda
    Greensboro, NC

    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.

  14. Don

    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.

  15. Michael T.
    Powder Springs Ga

    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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