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Sequoyah German Shepherds
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need a loving home!
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Last
updated 9/15/13
In recent years,
it has been brought to the attention of the veterinary community and
(breeding communities) that many of the herding breeds of dogs have
a genetic predisposition to adverse drug reactions to a variety of
different drugs. It has long been known that the collie breeds
(Rough Collies, Smooth Collies, and Border Collies) and many of the
sight hounds have been genetically predisposed to this, however,
more recently some of the other breeds have become noted for it as
well. Though it's not terribly common in the German Shepherd breed,
it is common enough to make note of it here, I think.
These drug sensitivities result from a mutation in the multi
drug-resistant gene (MDR 1 gene). The problem first came to light
back in 1983 when several collies died from ivermectin poisoning.
Since then, more drug sensitivities, as well as more "sensitive"
breeds have been discovered.
Breeds affected
by the MDR1 mutation (frequency %)
|
|
Breed |
Approximate
Frequency |
|
Australian Shepherd |
50% |
|
Australian Shepherd, Mini |
50% |
|
Border Collie |
<
5% |
|
Collie |
70 % |
|
English Shepherd |
15 % |
|
German Shepherd |
10 % |
|
Herding Breed Cross |
10 % |
|
Long-haired Whippet |
65 % |
|
McNab |
30 % |
|
Mixed Breed |
5
% |
|
Old English Sheepdog |
5
% |
|
Shetland Sheepdog |
15 % |
|
Silken Windhound |
30 % |
The MDR1 gene is responsible
for ensuring that the body's natural P-glycoprotein's function normally by
protecting the body from toxins. It does this by acting as a transport to move
substances from one cell to another. P–Glycoproteins are normally
extensively distributed in the blood barriers as well as a few other major
organs. In MDR1 affected dogs, the function of the P–glycoprotein is
compromised so therefore the blood brain barrier is compromised. If toxins
leak across the blood brain barrier, they entered the central nervous system
causing reactions such as excessive salivation, ataxia, seizures, blindness,
respiratory problems, or even death.
DNA testing is now available through Washington State University. There are
three possible results of testing – clear, carriers, and affected. Dogs
that are....
-
"Clear" (+/+) for MDR1
- should not exhibit any drug sensitivities
and pass on only healthy genes to their offspring.
-
"Carriers" (+/-) of the MDR1
- may experience some drug sensitivity
& can pass on either a healthy or a defective gene to their offspring.
-
"Affected" (-/-) by MDR1
- will have drug sensitivities and will
display toxic reactions to a wide range of drugs.
Testing for the MDR1 gene mutation allows us to not only make sure that we don't
inadvertently give a medication to a dog that can not handle that drug, but it
also allows us to make sure that when breeding, we are not perpetuating a
problem in the breed.
There are many
drugs that should be avoided in MDR1 affected dogs. There are
some other drugs that are known to be pumped out of the brain by the
MDR1 gene but also appear to be fairly well tolerated by dogs
with MDR1 mutations.
Avoid Medications: Some of the medications
or drugs that should be strictly avoided in MDR1 affected dogs
include:
-
Acepromazine (tranquilizer and pre-anesthetic agent)
-
Butorphanol (analgesic and pre-anesthetic agent)
-
Erythromycin
-
Ivermectin (antiparasitic agent)
-
Loperamide (ImodiumTM; antidiarrheal agent)
-
Selamectin, milbemycin, and moxidectin (anti-parasitic agents)
-
Vincristine, Vinblastine, Doxorubicin (chemotherapy agents)
-
Domperidone
-
Etoposide
-
Mitoxantrone
-
Ondansetron
-
Paclitaxel
-
Rifampicin
Tolerated Medications: Some of the drugs that
are known to be fairly well tolerated in dogs with in the ER one
mutations include:
-
Cyclosporin (immunosuppressive agent)
-
Digoxin (cardiac drug)
-
Doxycycline (antibacterial drug)
Generally Safe Medications: Here are a few of
the drugs that are pumped out by the protein produced by the MDR1
gene, but appear to be safely tolerated in dogs with the MDR1
mutation:
- Morphine
-
Buprenorphine
- Fentanyl
(opioid analgesics or pain medications)
Here is another table I found showing three
classes of drug compounds which includes some drugs NOT approved for
dogs:
-
Class A includes substances that have been
proven to pass through the blood-brain barrier in MDR1-affected
dogs and cause problems
-
Class B lists substances which have shown
interactions in animal tests
-
Class C substances can be given without
problems, even to affected dogs:
|
Class A |
DO NOT USE
in dogs with MDR1 affected dogs (-/-) -- they are likely to
experience drug toxicity following normal doses of the
drugs listed here. |
-
Anti-Parasitic drugs:
-
Ivermectine substances:
Diapec®, Ecomectin®, Equimax®,Eqvalan®, Ivomec®,
Noromectin®, Paramectin®, Qualimec®, Sumex® &
Virbamec®
-
Doramectine substances:
Dectomax®
-
Moxidectine substances:
Cydectin® & Quest®
-
Anti-diarrheal:
Loperamide substances
(Immodium®)
-
General antibiotic:
Metronidazole
(Flagyl ®)
|
Class B |
Toxic reactions have been known to occur so only use
under the close supervision of your vet |
-
Cancer treatments (Cytostatics):
Vinblastine, Doxorubicine, Paclitaxel,
Docetaxel, Methotrexat & Vincristine
-
Glucocorticoids: Dexamethason
-
Immuno-suppressants:
Cyclosporine
-
Heart glycosides:
Digoxine & Methyldigoxine
-
Anti-arrhythmics (heart meds):
Verapamil, Diltiazem & Chinidine
-
Pain control:
Morphine & Butorphenol
-
Anti-emetics (sickness/vomiting):
Ondansetron, Domperidon and Metoclopramide
-
Antibiotics:
Sparfloxacin, Grepafloxicin & Erythromycin
-
Antihistamines:
Ebastin
-
Tranquilizers & pre-anesthetic
agents:
Acepromazine (ACE) & Butorphenol
-
Other drugs: Etoposide, Mitoxantrone,
Ondanestron, Paclitaxel, Rifampicin
|
Class C |
Can be used safely providing the correct
dosage is given. |
-
Morphine
-
Buprenorphine
-
Fentanyl (opioid analgesics or pain medications)
|
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