Large Animal Gi Pharmacology

Front 1

What animal cannot vomit?

Back 1

Horses

Front 2

What are 3 things to consider with younger foals and ruminants?

Back 2

1) *Volume of distribution
2) Diet
3) Dosage interval varies

Front 3

What are the 3 general indications of GI meds in large animals?

Back 3

1) Gastric ulcers
2) Postoperative ileus
3) Diarrhea

Front 4

What does it mean if there are more drugs available for a condition?

Back 4

Drugs are probably less effective

Front 5

How are drugs often administered to animals with diarrhea?

Back 5

IV or intrarectal because with diarrhea have a dysfunctional GI and mucosa is altered

Front 6

What is a special consideration of ruminants with oral administration?

Back 6

What the first compartment of the rumen will do to the drug
-Same w/ camels who are pseudoruminants so have a 1st compartment similar to ruminants

Front 7

When are antacids still used in ruminants?

Back 7

For rumen overload syndrome (grain overload, rumen acidosis, rumen impaction)
-Worry about pH of rumen bc of grain fermentation and release of lactic acids

Front 8

What are 2 antacids used in ruminants for rumen overload syndrome?

Back 8

1) Magnalax
2) Rulax

Front 9

What are 2 common "diseases" that H2 blockers are used for in large animal?

Back 9

1) Gastric ulcers
2) NSAID use

Front 10

True or false. If you find a gastric ulcer in a horse you definitely need to treat it.

Back 10

False, gastric ulcers are present in almost every horse, have to ask yourself if it's clinically significant.

Front 11

What are the signs of gastric ulcers in foals? Adults?

Back 11

adults: Mild GI signs of pain- poor performance, change in behavior, weight loss, rough coat (Very non-specific)
Foals: much more profound signs of pain including rolling and laying on their back
-*MAY SEE DIARRHEA IN FOAL BUT NOT IN ADULT

Front 12

True or false. H2 blockers can be used for GI neoplasia such as melanomas to provide some relief.

Back 12

True, but just relieving, not treating.

Front 13

What are the 3 commonly used H2 blockers in large animal medicine?

Back 13

1) Famotidine (Pepcid)
-Common in small animal
2) Cimetidine (Tagamet)
3) Ranitidine (Zantac)

Front 14

How often is famotidine administered in large animals?

Back 14

Every 24 hours
*Advantage
*Disadvantage=expensive

Front 15

What large animal(s) is famotidine usually used in?

Back 15

Foals

Front 16

Why is it bad to use a "polypharmacy" method to treating any disorder?

Back 16

Because anything over 3 drugs you can't predict the side effects of each drug and how they're all going to interact

Front 17

True or false. Not all drugs have side effects.

Back 17

False, ALL drugs have side effects, even oxygen has side effects

Front 18

What large animal(s) is Ranitidine usually used in?

Back 18

Foals, not as commonly used in adults bc of newer proton pump inhibitors, but is effect in adult horses

Front 19

How often is Ranitidine administered?

Back 19

Every 12-18 hours (can be up to 3X daily)
*More affordable than Famotidine

Front 20

What is the biggest disadvantage of Cimetidine compared to Ranitidine and Famotidine?

Back 20

Has more potential for renal damage, especially in an animal with renal insufficiency

Front 21

Why shouldn't you combine Cimetidine with metaclopramide, sulfate or metronidazole?

Back 21

Because Cimetidine has strong inhibition of Cyt p450 so may inhibit drug removal

Front 22

What large animal(s) is Cimetidine used in?

Back 22

Foals
Adult horses

Front 23

Why is Cimetidine not used very commonly in adult horses if the side effects aren't an issue?

Back 23

Have to give every 6-8 hours in adults

Front 24

True or false. There are antacids specifically designed for use in equids.

Back 24

False, there are no equine products so it is off-label usage

Front 25

What is the H2 blocker of choice in foals?

Back 25

Famotidine, more expensive but lowest frequency of administration which increases client compliance & more effective in foals

Front 26

What is the primary proton pump inhibitor used in large animals?

Back 26

Omeprazole (Gastrogard)

Front 27

True or false. Omeprazole is used off-label in adult horses.

Back 27

False, approved for use in adult horses, but not labeled for use in foals

Front 28

What is the primary therapeutic indication of Omeprazole?

Back 28

Used commonly in horses to treat and prevent gastric ulcers

Front 29

How often is Omeprazole administered?

Back 29

Effective and can be given once a day

Front 30

What is one downfall of Omeprazole compared to the H2 blockers?

Back 30

More expensive than H2 blockers
-Can be 50 dollars a day compared to 5 for Cimetidine

Front 31

True or false. H2 blockers are used more commonly in foals than Omeprazole.

Back 31

True because Omeprazole comes as a single dose in a tube for a 500 kg horse, so easier to use H2 blockers

Front 32

What is a huge benefit of the effects of Omeprazole compared to antacids?

Back 32

Omeprazole can almost completely eliminate acid production and once a day

Front 33

What is a way to diagnose gastric ulcers since the signs are so vague?

Back 33

Gastroscopy

Front 34

What is the mechanism of action of Misoprostol?

Back 34

Prostaglandin E1 analog

Front 35

What is the primary therapeutic indication of Misoprostol in large animals?

Back 35

Prophylactic when using long term/high dose NSAID use

Front 36

Why isn't Misoprostol used very often in large animal medicine?

Back 36

Not very affordable in large animals, but is used in small animals

Front 37

What drug is considered an "antiulcer" drug in large animal medicine?

Back 37

Sucralfate

Front 38

What are 5 therapeutic uses of sucralfate in horses?

Back 38

1) Gastric ulcers
-Small & large animals
2) Treatment for right dorsal ulcerative colitis (RDUC)
-Related to NSAID use
3) Treat esophagitis, gastritis, oral ulcers

Front 39

In horses with right dorsal ulcerative colitis, PROFOUND _____ is a clinical sign.

Back 39

Hypoproteinemia, bc all the proteins leak out through the colon

Front 40

True or false. There's acid production in the colon.

Back 40

False! That's the stomach

Front 41

What part of the intestines are particularly affected in horses on NSAIDs?

Back 41

Right dorsal colon --> RDUC
Get ulcers developing there don't know why it's so sensitive

Front 42

True or false. Sucralfate is also used in camelids.

Back 42

True

Front 43

How can you tell immediately if sucralfate is helping right dorsal ulcerative colitis?

Back 43

Proteins will increase rapidly after starting sucralfate treatment
-See it stabilize in about 72 hours

Front 44

Sucralfate is used in conjunction with _______.

Back 44

H2 blockers

Front 45

What are the therapeutic indications of sucralfate in camelids?

Back 45

Third compartment ulcers and diarrhea

Front 46

Does Dr. Schlipf believe that you have to give Sucralfate a half an hour before H2 blockers or Omeprazole?

Back 46

No and it's a pain in the butt! It can be used topically and there's minimal evidence involved with that..
Dr. Rouleax-give separate
Dr. Schlipf-give together

Front 47

What is one side effect of sucralfate?

Back 47

May decrease absorption of some drugs

Front 48

What are 6 commonly used prokinetics?

Back 48

1) Erythromycin
2) Lidocaine
3) Metoclopramide
4) Domperidone
5) Yohimbine
6) Cisapride

Front 49

Which drug is used as a prokinetic, but is not a true prokinetic?

Back 49

Lidocaine, but get indirect improvement in motility

Front 50

What are 2 therapeutic uses of prokinetics?

Back 50

1) Postoperative ileus (upper GI)
2) PRoximal jejunitis & duodenitis

Front 51

What is the mechanism of action of erythromycin as a prokinetic?

Back 51

-Motilin receptor agonist on smooth muscle
-Release of Ach and motility in the enteric nervous system--> increases contractions

Front 52

Where is the primary site of increased motility from erythromycin in small animals? Horses?

Back 52

-Small animals: stomach & proximal small intestine in most species
-Horses: Cecum and large intestine

Front 53

True or false. Erythromycin enhances gastric emptying in normal horses.

Back 53

True

Front 54

How is erythromycin administered for use as a prokinetic?

Back 54

High doses so CRI or IV, but prolonged use or CRI induces receptor down regulation and inhibition of activity
-Erythromycin is not first choice for a prokinetic

Front 55

How is lidocaine administered for use as a prokinetic?

Back 55

IV infusions (CRI)
Boluses are ineffective bc a very short half life

Front 56

What is the mechanism of action of lidocaine?

Back 56

-Suppresses primary afferent neuron firing
-Anti-inflammatory properties
-Direct stimulation of smooth muscle
-Substance P?
-Analgesic: think effects are more related to analgesic effects, pain decreases GI motility

Front 57

What are the signs of lidocaine overdose?

Back 57

Excitement and weakness
-Large bolus too rapidly= excitement or more commonly weakness

Front 58

What should you do if there's an obstruction of the IV line in a horse that's administering lidocaine and the horse gets a huge bolus and falls down in the corner?

Back 58

Shut off the drip and give the horse a few minutes and it will wear off bc of the short half life

Front 59

What is the mechanism of action of metoclopramide?

Back 59

-5HT-4 and 5HT-3 receptor agonist
-Antagonist at dopamine 1 & 2 receptors

Front 60

What is associated with the extrapyramidal signs caused by metoclopramide?

Back 60

Dopamine 1 and 2 receptor antagonist

Front 61

True or false. Metoclopramide can be administered as an IV bolus dose to large animals.

Back 61

False, what causes side effects, give as CRI

Front 62

True or false. Metoclopramide can be administered orally to horses with post-operative ileus.

Back 62

False, they usually have reflux so there's not point
-Some use metoclopramide orally but he doesn't believe it works very well

Front 63

True or false. Metoclopramide can be used for post-operative ileus.

Back 63

True, can be used but excitement is a big problem because of dopamine receptor antagonist

Front 64

What is the mechanism of action of domperidone?

Back 64

Antagonist at peripheral dopamine 2 receptors

Front 65

True or false. Domperidone is used for post-operative ileus.

Back 65

False, it's been shown to have a modest effect on experimental ileus, but not a lot of effect on promoting normal motility

Front 66

What is the mechanism of action of Yohimbine?

Back 66

Alpha-2 adrenoreceptor blocker
-Counteract sympathetic outflow in response to nociceptive stimulation and/or endotoxin

Front 67

What are the therapeutic uses of yohimbine?

Back 67

Reversal agent for xylazine
-weak effect on cecal emptying
-RARELY USED, but sometimes used in small ruminants

Front 68

Why isn't Cisapride used in clinics?

Back 68

Not available, was taken off the market because caused death, but can get compounded..

Front 69

What is the mechanism of action of Cisapride?

Back 69

5HT-4 and 5HT-3 receptor agonist
-Enhanced acetylcholine release from myentic plexus

Front 70

Cisapride is the same as _______, but without the antidopaminergic effects.

Back 70

Metoclopramide

Front 71

What parts of the GI tract is affected by Cisapride?

Back 71

Increased gastric, small intestinal and colonic activity

Front 72

What are the 3 therapeutic uses of Cisapride?

Back 72

1) Equine grass sickness
2) Large colon impactions
3) Precentative for post-operative ileus
-Use in UK

Front 73

True or false. Antiemetics aren't used in horses since they don't vomit.

Back 73

False, still use occasionally

Front 74

What 2 antiemetics are occasionally used in horses?

Back 74

1) Metaclopramide (upper GI prokinetic/gastric emptying)
2) Meclizine (Antivert)

Front 75

What is the mechanism of action of Meclizine?

Back 75

Piperazine antihistamine

Front 76

What are 2 therapeutic uses of Meclizine other than an antiemetic?

Back 76

1) Vestibular disease secondary to Otitis media/interna
2) Geriatric vestibular disease

Front 77

What is the mechanism of action of Buscopan?

Back 77

Anticholinergic effects via muscarinic receptors of smooth muscle cells
-Antispasmodic in horses: opposite of prokinetic, relaxes GI

Front 78

What are 2 uses of Buscopan?

Back 78

1) Rectal palpation
-Antispasmodic in horses
2) Esophageal obstructions

Front 79

What is the therapeutic use of charcoal?

Back 79

May decrease toxin absorption
-Used to decrease toxins, grain overload, overdose in humans

Front 80

What are 2 therapeutic use of metronidazole in large animals?

Back 80

1) Clostridial diarrhea (enterocolitis)
2) Antiprotozoal and antibacterial (anaerobes)
-Maybe anti-inflammatory effects...

Front 81

What varies when using metronidazole for clostridial diarrhea compared to anaerobic GI infections?

Back 81

Used 4 times a day for anaerobic GI infections, but only twice a day for clostridial diarrhea

Front 82

What is the therapeutic use of Cyproheptadine?

Back 82

Appetite stimulant (cats it works well)
-*Used in horses w/o great success

Front 83

What is the mechanism of action of cyproheptadine?

Back 83

Serotonin antagonist antihistamine

Front 84

What is a use of diazepam in camels and cats other than anti-anxiety?

Back 84

Appetite stimulant

Front 85

What drug is used for inflammatory bowel disease in small animals and horses?

Back 85

Corticosteroids

Front 86

What corticosteroid is most commonly used in large animals?

Back 86

Prednisolone
-Sometimes dexamethasone

Front 87

True or false. DMSO IV is commonly used in clinics.

Back 87

False, at least not at our clinic, Dr. Schlipf hates DMSO! thinks its ineffective, potential side effect=carcinogen

Front 88

*What is always a possible risk of steroid use in horses?

Back 88

Laminitis
-Make sure to discuss risk with owners first!

Front 89

What is acupuncture sometimes used for in large animals?

Back 89

Ileus and motility enhancement

Front 90

What is Saccharomyces boulardii used for in large animals?

Back 90

Beneficial effects in diarrhea demonstrated
-This is a probiotic

Front 91

True or false. Pepto bismo is used in large animals.

Back 91

True, this is Bismuth subsalicylate, people love to poor it in but no evidence it does anything

Front 92

What is mineral oil used for in large animals?

Back 92

For grain overload in horses to absorb some toxins

Front 93

When can mineral oil be used to bind soluble toxins such as endotoxin?

Back 93

Within 24 h, if longer than that it won't help

Front 94

What drug is used for horses who have too much sand or soil in their GI?

Back 94

Psyllium mucilloid (metamucil)

Front 95

What is the therapeutic use of Bio-Sponge?

Back 95

To adsorb clostridial toxins
-Have to give frequently and in large doses to be effective

Front 96

True or false. Motility altering drugs, such as Loperamide (Immodium), can be helpful in animals with diarrhea.

Back 96

False, avoid motility altering drugs in large animals w/ diarrhea
-Used in small animals

Front 97

What is the therapeutic use of MgSO4?

Back 97

May be effective for colon impactions, pulls water into the colon -best softening agent is water

Front 98

Why is phenobarbital used in animals with liver disease? Why do we need to monitor animals on phenobarbital?

Back 98

-Use in foals with punicterus (bilirubin deposits in brain and brain damage) from hyperbilirubinemia
-Because has effects on the liver

Front 99

What 3 bactericidal antibiotics are used in animals with a hepatopathy?

Back 99

1) TMS
2) Ceftiofur
3) Penicillin/Gentamicin
-Depending on problem could be beneficial

Front 100

What is the mechanism of action of flumazenil?

Back 100

Benzodiazepine receptor antagonist
-Use to reverse things like diazepam

Front 101

What are 11 drugs (groups) used in animals with a hepatopathy ranging from hepatic encephalopathy and acute hepatitis to cholidocholithiasis?

Back 101

1) Bactericidal antibiotics
2) Flumazenil
3) Metronidazole
4) DMSO IV
5) Corticosteroids
6) Colchicine
7) Vitamin K1
8) Folic acid
9) Vitamin B1
10) Reduce blood ammonia- Neomycin, lactulose, acetic acid
11) Increased branched chain amino acids in diet

Front 102

Why is metronidazole used in animals with a hepatopathy?

Back 102

Changes normal flora of GI

Front 103

What 3 drugs reduce blood ammonia?

Back 103

1) Neomycin: Changes GI flora
2) Lactulose: acidifies colon so decreases activity of microflora--> decreases ammonia production
3) Acetic acid: acidifies colon to reduce bacteria & ammonia

Front 104

What is the mechanism of action of DMSO IV, pertaining to hepatopathies?

Back 104

Dissolve calcium bilirubinate stones/debris in bile ducts (possibly)
-May help dissolve stone accumulation in bile duct