What are the L-lysine side effects?

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Purred: Sun Nov 1, '09 1:16am PST 
I posted a couple of weeks ago about my having a very bad Respiratory infection and everyone suggested I take 500mg of L-lysine per day when I'm sick. Are there any side effects with taking it?

I just got rid of my respiratory problem, but now I started throwing up just 3 days after I started taking the L-lysine. The bottle says~ NUTRA BIO.COM, L-Lysine HCI Pharmaceutical Amino Acid Powder 500mg capsules. It says it is 99.97% purity, I think on the web site it said 100% pure?? Dad quit giving it to me yesterday with all my vomiting.

Today I vomited twice, but did so 3 to 4 times in a row. I woke up in the middle of the night last night and vomited. I mostly, but not always vomit right after I drink or eat, either one!

My food has not changed, I'm eating the same food I have always eaten, except for the L-lysine. I don't throw up every time I eat or everytime I drink , I still have an appetite, but it's not quite normal, I don't eat as much as I would when I'm well, but I will eat can Science Diet. Like I said, I don't vomit everytime I eat or drink !! My dad can tell I don't feel good just by looking at me, but I'm not feeling real real bad like I'm about to die, I'm not mopping around or sleeping all day, I still want to go out on the porch and I'm still making my usual walk-abouts around the house. I'm still very loving and affectionate and I still like sleeping between my daddy's knees under the worm blanket.

I just puke a couple times a day. It's clear sometimes other times it's the color of my Science Diet food

My daddy also wants me to ask about my licking.. I have always liked to occasionally lick plastic, but I'm not only licking plastic more often than ever I'm also licking metal and the wall in my Dads bedroom .. whats up with all the licking?

I guess I'm going to the vet "again" Monday morning (lately I feel I might as well be living there) Dad says he will take me Monday unless I stop drinking and eating, or if I just get any worst, then hes going to take me to an expensive hospital thats open 24/7. He's wondering if he's gonna have to pawn his right arm to pay for the visit??

Thanks Guys !


headed for the- light.
Purred: Sun Nov 1, '09 2:53am PST 
I don't have any side effects from the lysine--it's just an amino acid. But, if you are getting the 500 mg all at once, I might try giving it in 2 servings-- the recommended dose is 250 mg twice a day. At any rate, with that much vomiting, Meowma says she doubts it's the lysine, and that you might try opening up a fish oil cap and eating it, in case there is a hairball or other blockage. It the vomiting keeps on, you really should see the vet asap anyway, before you get dehydrated or worse.

♥- Tasha- ♥

Cat; I'm a kitty- cat!
Purred: Sun Nov 1, '09 5:00am PST 
We give L-lysine 250 mg every day, and have no side effects from it either. BooBoo is right, maybe if you spread it out to 2 doses it would help.

I am not sure about the licking, you should probably see what the vet thinks about it. thinking


Purred: Sun Nov 1, '09 8:39am PST 
Yes, I have given her the L-lysine in 2 doses, 500mg because she is big at 20 pounds. I was giving her half a capsule in the AM and the other half at night.

She is 14 years old and has never had a problem getting her hair balls to come up before, but now that you mention it, I have not seen one in a while now. I find it hard to believe she can't get it up after all her throwing up!! She just threw up 3 times not 10 min ago right after eating, but then went right back and ate and drank a little just a second ago. She does not seem to be uncomfortable, she's now sitting in the living room grooming her self. Her eyes are wide, clear or full. She's nothing like she was when she had the respiratory infection, not at all!!

She also used the litter box about 40 min ago, I saw a wet spot.

By mistake I bought her a pack of the Friskies Hairball Remedy treats and because she liked them so well I bought more, I give her 3-4 at a time, she likes soft treats over the crunchy. The Hill's Science Diet I feed her is Hairball Control Light, I wonder if the Hairball control and hairball treats might be causing a problem?

It's hard to believe she can't get a hairball to come up, but I'm willing to look at any and everything to make sure!!

Can you tell me more about the Fish Oil?? What should I get, where and how much do I give her? Do I add to her food or do I try and force it down her with a dropper or syringe? She weighs 20 pounds. If it is a hair ball? how long will it take for the fish oil to work? Does it always work ?

Thank you all..

Edited by author Sun Nov 1, '09 8:42am PST



headed for the- light.
Purred: Sun Nov 1, '09 1:43pm PST 
Since it's a natural animal product, you can just get the gel caps for people, and cut one open--lots of kitties will lick it right up. (If your people don't take fish oil already, they should--it's good for the heart!) If not, you can put it in a syringe and squirt it in the kitty's mouth. The 1000 mg cap has about a half teaspoon of oil in it and seems to be about right. It won't even hurt anything if a cat eats the outside, because it's just gelatin (also from animals) I have a problem with constipation, and take meds for it; oddly I seem to have more trouble if I get too much fiber, and will start vomiting, because the blockage is in the intestine--not the stomach, where it could come up. Cutting the 'indoor' or 'hairball control' foods half and half with the regular kind seems to work better in my case. I hope you feel better soon!

Edited by author Sun Nov 1, '09 1:45pm PST



Education is the- Key
Purred: Sun Nov 1, '09 4:23pm PST 
We give L-lysine with no side effects, have been doing it for a long time. Its an amino acid so it should not make your cat throw up.
I would not give those treats, they do not have good ingredients in them. I would also recommend switching the food you feed, it could be now starting to cause problems. Just look at the ingredients, powdered cellulose is basically sawdust, there are so many grains and carbs in this food. Does the food you feed have BHA/BST listed?? that is a known carcinogen. None of these ingredients are fit for an obligate carnivore.
Please read a site on called catinfo.org about feline nutrition, that is just one site, I can give you many more. Hope you start to feel better soon. smile


Hobbit Kitty,- Mighty Hunter
Purred: Mon Nov 2, '09 12:36pm PST 
I don't think it's the lysine either, but you can cut it out for now in the interest of simplifying everything and isolating other factors. If the licking behavior is new (the walls and metal), and she usually throws up right after putting something on her stomach, I'd say a trip to the vet is definitely in order. It definitely sounds like something is bothering her tum.

Fish oil is good for skin and coat, and for general health. You can get the human grade stuff - it's probably better quality and certainly cheaper than anything made for pets.

I agree with Shadow about the low quality of Science Diet, but this sounds like a more acute problem. Maybe after this issue is resolved you could check into other foods. It is great that you are feeding canned and not kibble!! way to go


RESPECT The- Star!
Purred: Mon Nov 2, '09 3:22pm PST 
Mine only get L-Lysine when they are sick, but the hard core campaigners, give it all the time. I think its because they have a higher risk of exposure/stress, going to a show every weekend, and some fly all over the US to shows.

I have never heard one bad thing about L-Lysine, and with show people, if there is a bad product out there, everybody knows about it, and actually, we tend to find out, about it, before the general public, per say. When one has a very expensive show cat, and there is an issue with any product, everybody and their brother, "knows about it". It is all over the show hall, and put on every cat show board.

Science Diet, is one, that is trashed in all show halls, and on every cat show board.

It has exyoxquin, which I can't spell, mol, in it, the others can prob spell it right, and tell you all about it.

I tend to think, your throwing up issues, are due to the Science Diet. I used to feed it, and was put on the CD and SD, by another vet, after a bout of crystals. Not only did the crystals come back, but I had throwing up issues too. Found out how bad Science Diet really is, at a show.

When I switched to a grain free food, no more crystals, no more throwing up.

As far as the L-Lysine, you can get it at any drug store, in the vitamin section. You want the capsules, so you can break them open, and mix the powder with the wet food.

Bumpurr gets one, once a day, the kittens get 1/2 twice a day. It goes by the weight of the cat, and the what the issue is, your vet can best advise you, how much to give and how often. One should really not be giving it, even tho you can get it over the counter, unless they know what they are treating for, and their vet is aware of it, and their vet can best advise the dosage.

What you are looking for, is the bottle should say,

Contains NO sugar, starch, artifical colors, flavors, preservatives, corn, soy, yeast, wheat, grain, gluten, egg or milk products.

If the cat is throwing up, more than twice, you need to take her to the vets, and ask for x-rays and a CBC blood panel.

Best of luck.

big grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grinbig grin

Miss Tiny- Burr Burr

Love and adore.
Purred: Tue Nov 3, '09 9:06am PST 
lysine is an ammino acid...i dont see who it could make her vommit. is there anything extra in the lysine that maybe she dosnt handle?


Purred: Wed Nov 4, '09 3:29pm PST 
The vet said he thinks she has a hairball caught up.. She doesn't have a fever so he suspects that is what it is. In 14 years she has never had a problem getting rid of them.. First time for everything I guess. I can't believe she could not get it to come up when she throws up, it's a pretty violent act her throwing up..

He gave her Laxatone and said for her to take 1 teaspoon per day and we should see results in 3 days, today is the 3rd day and she just threw-up but no hair ball yet!! It must be huge???

Has anyone ever heard of a hair ball that just won't come up no matter what you give her?? Just wondering what the worst case scenario with a tough hairball could be? what signs to watch for.

In 14 years she has never been sick, but this year we have had 3 problems where she got very ill and the vet had to be seen..
It just breaks my heart to see her sick and suffering.

Thanks everyone.. you all are so Great!!!

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