What are the side effects of gabapentin?

I've been taking 3600mg of gabapentin a day to dull the pain in my feet for about 3 years now, and all 3 things that you mentioned are things that I occasionally have to deal with. Sometimes my short term memory just disappears. I'll be in the middle of a sentence, and then I forget what I was even talking about.
I also have trouble speaking sometimes as well, I'll know what I want to say, but the words don't come out right, I have to stumble for them, and it's embarrassing. And I occasionally have trouble swallowing, even without trying to swallow food or any liquid. Just the act of swallowing takes some effort.

I've just assumed that these were the kinds of things that happen as you get older, I turned 66 last month. I'm the oldest member of my family now that our parents are gone, as well as our older sister who passed away in 2020, so I don't have anyone to talk to about this. They might be side effects from my medication, but how would you determine something like that? I'm taking 12 prescription drugs currently for multiple issues, including neuropathy in my feet.
I think I'm stuck between a rock and a hard place.

Good evening @mrmacabre, I have joyfully read your post this evening. Right now I have 12 different drug/pill medications that are given to me by my partner and my at home nurse on a daily basis. In addition I have oils and skin lubricants that I apply during both the evening and a specific time during the day. A couple of weeks ago I became 83 years old. My most grateful gift was an at-home dinner celebration with nurses, doctors, responsive neighbors, generou house keepers and bed makers. My surprise gift was waking up to see at least 5 squirrels and a group of last years chipmunks who had climbed up on the porch even though it was snowing. If they can come out to support their health......then we can to. Good health and warm happy Spring. Chris

@cate321
It could be from the Gabapentin. You may want to lower the dosage. Have you tried spinal injections? Has your specialist suggested physical therapy or surgery to to address the source of your leg pain?

You may want to see a pain management specialist to help you with treatment options.

My husband recently started taking 300mg of gabapentin for nerve pain going from his hip to his foot. He immediately noticed being more fatigued during the day. He has moderate cognitive impairment and I noticed it was worse, so he is trying just 100mg a night to see if it helps at all, but he is going to go in again for an ultrasound guided cortisone injection, which he had two years ago for the same issue and helped a lot.

I started with a lower dosage several years ago, and as the pain in my feet intensified, my doctor increased the dosage to what it is now, which is the highest he'll prescribe. I've seen a neurosurgeon after my neurologist said he couldn't do anything more for me to see if he could find anything physically that might be causing it. He looked at the most recent MRI of my lower spine to see if the spinal stenosis there might be causing the nerve damage, but he determined that it wasn't severe enough to warrant surgery, or be the cause of my pain.
I saw a pain specialist a few years ago, and they tried a spinal injection to see if that might help, but it had no affect what so ever.
I don't suffer from leg pain per say, it's the pain in my feet from the neuropathy, and the pain in my knees and hips from osteoarthritis that I suffer from every day, and have for the past 10 years.

I take 600mg of gabapentin 3x a day. I have Chronic Fatigue Syndrome and Fibromyalgia for about 40 years now, so I have lived with the fatigue, mental fog, etc for a long time. The symptoms come and go depending on stress and exertion. What I have noticed since taking the gabapentin is that the symptoms don't seem to lessen when I am well rested and not overly stressed. I have also noticed that sometimes, especially when laying down, swallowing takes effort.
My reason for the gabapentin is nerve damage from a fall. I got up to quickly from laying down and fell on my left side. I cracked 2 ribs. About a week later the whole side of my leg went numb from hip to foot. There is still some numbness there. I tried to cut back on gabapentin. Just cutting midday dose to 300mg and taking 600mg other 2x caused what felt like sparklers going of under the skin of my thigh multiple times a day. It was intense and when it got to 8 or more times a day, I added that 300mg back. It took almost 2 weeks after that before those mining explosions stopped. For me, I have to stay on gabapentin at this high dose and accept side effects. If you can do without gabapentin and you don't like side effects, do that.
I do sleep better these last 5 years since I started gabapentin.

Not gabapentin effect

Made me wonky, dizzy, and didn’t help my nerve pain. No thank you. It also causes cognitive decline. It didn’t last because I quit it

I switched to Lyrica and have less side effects.

Thank you for your transparency and knowledge.