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Discussion on CNS Rxn to Ivermectin/Praziquantal?
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Member:
Penner
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Posted on Monday, May 17, 2004 - 7:58 pm:
Hi,
Our 13YO Arab gelding (up to date on all his shots incl all encephalitis, rabies, west nile etc) developed a corneal ulcer 1 mo ago. We caught it right away, & had the only vet opthalmologist (a dog vet) in AZ look at him (by the horse vets persuading the dog vet).
In his eye, he was put on Plasma, chloramphenicol eye ointment, atropine eye ointment, "triple Abx" eye ointment, natamycin, ocuflox, antifungal eye ointment Q 4 hrs, with banamine for pain orally BID. This went on for a week. It got no better so they did surgery (not a "flap") to remove a fungal plaque from the eye. He spent 5 days in the hospital. Cultures grew a fungus. They said 70% chance of getting his eyesight back.
The 3rd week, he came home. He was put on the same regimen but minus the plasma & plus acetylcystiene.
2 days after being home, my husband wormed him orally with ivermectin/prazequantal combination (the 1st time this horse has had this, he only has had ivermectin before).
In a day or 2, he became very lethargic, overall uncoordination (no focal neurologic deficits), DrOoling, resting his teeth on the stall wall, dehydrated.
Called the vet out, she was pretty worried about brain swelling, so she gave him IV fluids but with DMSO & so back to the hospital he went.
They stopped everything except the eye antifungal ointment & watched him overnight. They are thinking toxicity from ivermectin/prazequantal, encephalitis is way down on the list as his shots were current. They sent him home the next day, minus the atropine, but on everything else.
5 days later now, he is really still the same, & has this glassy eyed look that he doesn't seem to be recognizing anything/one. He still stumbles, & has repetitive slowly walking around & around the paddock.
My questions are:
- what do you think is going on?
- I can't seem to find any info on ivermectin/prazequantal toxicity either, does anyone know where?
- If this is toxicity or drug interaction, what is the prognosis?
Sorry for this long post, but I don't really know what to think anymore.
Thanks all.
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Member:
Shagya
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Posted on Monday, May 17, 2004 - 11:08 pm:
Hi Penner,
sorry to hear about your unfortunate case. Since I started deworming with Ivermectin/Praziquantal too, I looked around the web to see what I could find.
While I haven't been able to find very much, I did come across a warning on the Farnam website that might be of interest to you. It is regarding their Moxidection/Praziquantal dewormer ComboCare Gel.
In their product details they say that "Transient ataxia, incoordination, lethargy,
depression and DrOopy lips and eyelids may be seen when very young or debilitated animals are treated."
It doesn't specify debilitated animals, but I could imagine that all the drugs and surgery had a weakening effect.
I hope this helps you out a little bit in your research. I've pasted the applicable paragraphs to the end of this message and also included a link to the PDF file at Farnam's website.
Good Luck, Marc.
"ANIMAL SAFETY
ComboCare (moxidectin/praziquantel) Equine Oral Gel can be safely
administered at the recommended dose to horses and ponies of all breeds at
least 6 months of age and older. Transient ataxia, incoordination, lethargy,
depression and DrOopy lips and eyelids may be seen when very young or
debilitated animals are treated. In these instances, supportive care may be
advisable. (…)
To report adverse drug reactions or to obtain a copy of the Material Safety Data Sheet (MSDS) call (602) 285-1660
WARNINGS
Extreme caution should be used when administering the product to foals, young and miniature horses, as over dosage may result in serious adverse reactions. Do not use in sick, debilitated, or underweight animals. Do not use in horses or ponies intended for food. "
(Source: https://www.farnamhorse.com/combocare/CC_Insert.pdf )
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Member:
Hwood
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Posted on Monday, May 17, 2004 - 11:14 pm:
Gloria,
I have no expertise to offer you, but when I read your post, my heart ached. I hope that the vets will be able to come up with a plausible explanation very soon . . . and be able to prescribe appropriate and successful treatment for your gelding.
This must be a very hard thing for you and your family right now. It sounds so bizarre. I await input from Dr. O. and other HA members.
Take care.
Holly
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Member:
Penner
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Posted on Tuesday, May 18, 2004 - 1:33 am:
Thanks guys for your thoughts (I need some more from the HA community, please!)
Minor correction to my Arab's story:
1. it was a "Path Report" not cultures that showed a fungus in the plaque. (Fungal cultures can take weeks to grow).
2. The "antifungal eye ointment" is Itraconazole.
3. the statement "after surgery, he was put on the same regimen but minus the plasma & plus acetylcystiene...", should read:
"He was put on the same regimen but minus the plasma & plus acetylcystiene AND BACTRIM (a sulfa drug).
This information is probably splitting hairs, but I wanted to be completely accurate, as to me, this isn't exactly the outcome I was hoping for, & am pretty sad. Hopefully, time will heal. Saying my prayers.
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Moderator:
DrO
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Posted on Tuesday, May 18, 2004 - 7:19 am:
Hello Penner,
Sorry to hear about your recent troubles. Though we cannot rule out a individual sensitivity the deworming is very low on the list of possibilities, unless your horse had access to blooming nightshade.
In one of the most illuminating safety studies done to date, 40 pregnant mares were given a 3X overdose every 2 weeks for a year. There were no ill effects on the mares or their foals when born. Am J Vet Res. 2003 Oct;64(10):1221-4. Evaluation of the safety of ivermectin-praziquantel administered orally to pregnant mares. For more on this see Equine Medications and Nutriceuticals » Dewormers: Anthelminics » Praziquantel.
I cannot find any clinical reports of toxicity with this combination. There has been an odd report of ivermectin toxicity at normal doses in horses that were exposed to blooming nightshade. It was conjectured that the plant increased the permability of the blood brain barrier to the ivermectin. If death does not occur, complete recovery usually occurs with good nursing support. There are no clinical reports of praziquantel poisoning though our article lists what I could find in pharmacology books (no references).
There is not enough information in your post for us to know what is going on. Assuming there are no other relevant clinical signs or laboratory findings, I agree it sounds like neurological disease that localizes to the cerebrum and for a list of rule outs and some ways to differentiate them see, Equine Diseases » Nervous System » Diagnosing Diseases of the Nervous System. Important to realize is that none of the vaccines you list are 100% and so rabies and the other viral encephalitis disesae should still be considered a possiblity and more likely than the dewormer depending on the incidence of these diseases locally.
If there is a relation to the deworming the most likely event would be it killed a migrating parasite larvae in the brain resulting in a cephalitis, but I do not know any tests you can do for this short of MRI.
DrO
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Member:
Sunny66
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Posted on Tuesday, May 18, 2004 - 10:41 am:
I'm so sorry Penner....Sending positive, healing thoughts to you and your boy!
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Member:
Penner
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Posted on Thursday, May 20, 2004 - 1:57 pm:
Hi All,
Thanks for your thoughts. Took him to the vets today, the eye is doing better, his demeanor is improved (not a lot, maybe 1-5%).
They are sending out the acute serum today for the arboviruses & WNV. The convalescent serum will be sent next week.
He never spiked a fever, even off banamine (that day they observed him), & feel that if it was viral, he would have. They also said to me, that altho not ruled out, if it was rabies, he would be dead by now (as its 7 days since he started showing neuro signs). His blood chemistries (lytes, liver etc), & CBC with diff have always been in the normal range.
Apparently, there is a British DVM that wrote the article on foals & moxidectin/praziquantel. He is supposed to be in town, so they are going to ask him about this.
Next week, they are looking at his eye again (routine check), so if his affect is not better, they will do an LP for EPM (altho opposums are rare around here).
Just posting an update, as I still don't know what to think.
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Member:
Penner
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Posted on Wednesday, Jul 28, 2004 - 3:07 am:
Hi,
Been a while since I've posted, a lot has happened & I couldn't bring myself to think about this.
Shezaad 's neurologic appearance got better (altho he was encephalopathic for 1 - 1.5 weeks),to he where seemed back to his normal demeanor, & the vets thought so too (kinda a sh*thead - but we loved him anyway  ).
His eye got better (after 2 mo of every 6 hr medication - but we did it!).
So, 1 week after after the stitches shutting the eye were taken out ( & 3 weeks post recovering from the encephalopathy), we rode him.
We only rode him (walk/trot - no cantering) in the arena, but we did only trot after a cow. We did not rope, only threw the rope on the ground - everything seemed OK - he did not spook, just seemed to know his old job, & seemed happy.
So, Phil took him on trail around our house, trails that Shezaad's been on for 4 yrs. I was following Phil & saw the whole thing.
Phil took Shezaad up a small hill (really small, just a dip in the road type thing). But, there was a 8" tire rut ON THE LEFT (caused by the **&*&&&** ATVs illegally ridden by 8 year olds around here) in the trail that Phil didn't see, the horse's foot slipped in the tire rut, the horse lurched to the right, but lost his balance & fell on a rock. The horse split his knee open to the bone...
I can't tell you how sick I felt watching this. I still feel sick, & can't get out of my mind's eye, this catastrophic scene...
We walked a 3 legged horse home, called the emergency vet.
Took him to the emergency vet, they did Xrays, flushed the joint capsule - but it leaked fluid & was badly damaged too. They told me that horse's knees are so "reactive" in healing that he would never be able to bend his leg again - even for shoeing etc. They said there was no hope - we had to put him down.
In retrospect, I guess I have a couple of problems with this:
1. Our vet never did a PHYSICAL Neurologic exam - post-encephalopathy (they sure made sure they did when we have subsequently bought another horse...)
2. WHY do parents let their friggin kids ride these ATVs illegally & tear up the desert, causing incredible erosion!!!
You have to be 16 yrs old & have a license, no riding the ATV double, no tailgaiting a horse (DUH), no racing around a blind curve to run into a 1200# horse that you couldn't see because you are 8 yrs old & have no sense & driving too fast & driving illegally, & ruining the desert etc.)
Ie: if you have to be 16 yo to drive a car at 40 mph, then why is it allowed (read: laws ignored by parents) to drive an ATV at 8 yo at 40 mph & on the streets too??? But thats what I have to put up with. Sorry, have to vent...
All Shezaad's tests were negative: ALL encephalopathies (West Nile, EPM, rabies, EW, St Louis etc). This was an idiosyncratic reaction to this wormer, I guess. But I want to let everyone know who may have the breeding of this horse (see my previous posts).
Loved this horse...
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Member:
Frances
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Posted on Wednesday, Jul 28, 2004 - 6:53 am:
Oh Penner .... I'm so very sorry ...
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Moderator:
DrO
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Posted on Wednesday, Jul 28, 2004 - 7:56 am:
My deepest condolences Penner. Though it cannot be removed from the list of possibilities the dewormer is still a very unlikely cause of this problem: do you remember what the Equine Herpes Virus titer was?
DrO
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Member:
Mrose
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Posted on Wednesday, Jul 28, 2004 - 9:49 am:
What a tragedy! I'm so sorry!!
We have problems with ATV's around here too-and it's not always kids. Many ATVers seem to have the attitude that the world is theirs to ride over and the rest of the population be damned. I have to say that many of these people aren't locals in our area, but come up from Las Vegas to "run wild in the wilderness" up here. It's so bad in summer that I won't use the trails on summer weekends.(We also have lot of people shooting hither and yound. I keep hoping they'll thin out the ATV population.)
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Member:
Penner
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Posted on Wednesday, Jul 28, 2004 - 11:26 am:
Thanks everyone for your thoughts.
Sara, yep, we have the shooters too, & I keep hoping the same thing. & did you know, (I've found out) I bet all those shooters are wearing earplugs, as most do. I have carried an Acme Thunderer whistle for years (supposedly can be heard 1/4 mi) to let them know I'm around.
But now I find out about this earplug thing, they are not even hearing the whistle. Then another thing they do, is have the music (I use the term lightly), jacked up all the way, so they can't even hear you between firing...
None of the ATVs or shooters were around when we moved here 4 yrs ago, we weren't even on the maps back then & I liked it that way.
Dr O, I will call & get the titers for you.
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Member:
Deggert
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Posted on Wednesday, Jul 28, 2004 - 12:31 pm:
Penner,
I am so sorry about your loss of Shezaad. I know so many people who have had a bad year with horses including myself. You mentioned to note his breeding in previous posts but I couldn't find it other than Arabian. I have 5 Arabians myself and I believe some lines have idiosynracies with wormers, vaccines and/or sedation etc. I have used the ivermectin/praziquantel on 2 of my horses with no problems. I have held off on the 27 year old and of course the one who was pregnant. You know you did the best for him and thats all we can do. I hope you find another to fill the space in your heart.
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Member:
Penner
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Posted on Wednesday, Jul 28, 2004 - 1:03 pm:
Hi Debbie, I found the old post. He is (was) a Straight Egyptian Arabian, & by linebreeding percentages, he was 54% *Morafic himself!
His bloodlines are:
Sire = Ibn Morafic+++
Dam = Flaby Bint Sharaf.
Ibn Morafic by *Morafic by Nazeer.
Flaby Bint Sharaf by Moniet El Sharaf by *Ibn Moniet El Nefous
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Member:
Mrose
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Posted on Friday, Jul 30, 2004 - 9:54 am:
Penner-Oh, great. I never thought about ear plugs! I just try during the week and where I think shooters won't be. During "The Hunt" I refuse to leave home!
btw-Your guy was extremely well bred! Terrific blood lines. We bred Egyptian Arabians and stand a stallion who is a *Morafic/*Tuhotmos grandson, as well as one who has *Ibn Moniet El Nefous lines. So, you can see I'm predudiced!
Although I'm sure Shazaad won't be forgotten, you'll find another to fill the void he left. Each seems to have his own special personality and gifts to give us.
And,If you want another Egyptian, I can help you out!
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Member:
Penner
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Posted on Friday, Jul 30, 2004 - 8:27 pm:
Sara, thank you, yes he was my handsome guy.
Dr O,
Here is the clinical & labs tests that you were wondering about... I will also put in the clinical reasons the vet(s) told me why they did what they did in [brackets].
TESTS:
1. Arboviruses
Serum Acute: 5/21/04 E & W both 1:80
Serum Convalescent 5/28/04 East: 1:40 West: 1:80
[so they considered this negative as its only a 1 fold change. Also, they said that a (+) is a four fold change. They did not do Venezuelan as they said its not been in this country for 40 yrs].
2. Serum IgM capture Elisa for West Nile Virus was (-).
3. Serum Western Blot for EPM was (-).
4. Herpes: not done. Their reasoning...
[they said to me that Herpes viruses serotypes 1 & 4 may cause a myelitis, but he had been vaccinated for those serotypes. They also said that serum titers for Herpes viruses are not reliable. If a CSF herpes titer had been done, it could maybe have been suggestive via increased protein, xanthrochromia etc, but not diagnostic.
Also they said his clinical picture did not fit a myelitis as he had no ascending paralysis symptoms, no decreased anal reflex, no urinary paralysis symptoms & that in myelitis, horses are alert.
Shezaad was encephalopathic, but had no 1 sided symptoms or any of the above-mentioned symptoms. His clinical picture resembled more a hepatic encephalopathy, but his liver enzymes remained normal thruout the course.]
They think this may have been a drug interaction, where the wormer crossed the blood brain barrier due to the effects of the other medicines - but who knows for sure.
I personally, will be staying away from the wormer, & just go back to using ivermectin which I never had problems with before.
Hope this helps - would be interested in any other ideas you have & I'll ask my vet again.
Sorry this was so long winded!
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Moderator:
DrO
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Posted on Saturday, Jul 31, 2004 - 12:10 pm:
Ohh Penner, the vaccine is not protective against the neuro form, if fact, there is some weak evidence it may predispose to it, see Equine Diseases » Nervous System » Equine Herpes Encephalopathy for more.
DrO
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Member:
Penner
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Posted on Saturday, Jul 31, 2004 - 1:37 pm:
Hi Dr O,
Thank you for answering me. I read the article, & I agree, it is possible. I am thinking if this was Herpes, he may have picked it up in his loooong stays at the vet hospital, or re-activated a latent infection due to the stress of surgery?
However, he did not have any of the other symptoms. He only was EXTREMELY lethargic - & therfore had difficulty standing D/T weakness, but never got to the point he was recumbent.
When you said in the above post the vaccine is not protective against the "Neuro" form, which did you mean: myelitis, encephalitis, or myeloencephalitis?
Also, do you know if equine herpes is a zoonosis?
Thanks again, I really appreciate your help.
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