Factors Modifying Drug Disposition And Response

Question 1

What are some ways species differences can affect drugs.

Answer 1

Anatomical- ruminant or non rum.
Physiological
-carnivores acidic urine
-herbivores alkaline urine
Biochemical
-drug metabolizing enzymes 
-- cats are deficient in glucoronyl transferase.

Question 2

What causes cardiovascular collapse in boxers?

Answer 2

Phenothiazines

Acepromazine

Question 3

Collies are sensitive to _______, which can cause CNS depression, ataxia, tremor, salvation and coma.

Answer 3

Ivermectin

Question 4

This drug, when given to Australian terriers caused no sedation/analgesia but does cause salivation, tachycardia, muscle tremors and convulsions.

Answer 4

Droperidol/fentanyl

Question 5

Genetic factors can cause unwanted drug effects.

ABCB1 (formerly MDR1) gene deletion affects whom and how?

Answer 5

Collies- this gene normal encodes p-glycoprotein.
Mutation or deletion means less p-go produced
35%homozygous in North America

Question 6

Genetic factors can cause unwanted drug effects.

C-15A SNP, what be that?

Answer 6

Mu-opioid receptor gene

OPRM1)- dysphoria (freaking out

Question 7

How does gender/gestation affect drug stuff.

Answer 7

Women are complicated, and then they get pregnant and men should run and buy chocolate. But really, know what you can’t give during gestation.

Question 8

Body condition score

Answer 8

When in doubt lower the dose, large amounts of fat can bind lipophilic drugs.

Question 9

Young animal drug effects

Answer 9

• decreased ME
• inc. BBB permeability
• dec. Plasma protein binding
• inc. Total body water
• susceptible to adverse effects.

Question 10

Tetracyclines young animals and go!

Answer 10

Yellowing of teeth

Question 11

Fluroquinolones young animals!

Answer 11

Cartilage damage

Question 12

Glucocorticoids young animals

Answer 12

Premature closure of epiphysis

Question 13

When does drug clearance reach adult capacity?

Answer 13

Not typically until 12 weeks of age.

Question 14

Factors related to old animals.

Answer 14

Dec. M&E
Dec. CO & hepatic blood flow
Chronic diseases
Changes in body composition
-dec. Lean body mass
-inc. Body fat
-dec. Total body water.
-dec plasma proteins

Question 15

Liver disease drug effects

Answer 15

Decreased drug metabolism

Question 16

Renal disease causes

Answer 16

Decreased drug excretion

Question 17

Congestive heart failure causes

Answer 17

Decreases drug distribution and excretion

Question 18

Calm animals need what kind of dosage on CNS depressants.

Answer 18

Lower doses than aggressive or excited animals

Question 19

What is idiosyncratic drug reaction?

Answer 19

Unpredictable, abnormal, non dose dependent, requires drug withdrawal, caused by reactive metabolites and they can occur on first exposure!

Liver damage by griseofulvin in some cats

Question 20

What are the three broad factors that relate to veterinary pharmacology

Answer 20

Factors related to
The animal
The drug
The environment

Question 21

Hypersensitivity to drugs

Answer 21

Prior exposure is necessary
Cross sensitivity
Type 1 hypersensitivity( allergy and or anaphylaxis)

Question 22

What drugs are antigens?

Answer 22

Blood, plasma, protein hormones.

Question 23

What drugs are haptens

Answer 23

Penicillins sulfonamides aspirin

Drugs that are too small to directly bind to the antibody.

Question 24

What is tolerance

Answer 24

Gradual decrease in responsiveness to chronic drug administration.

Question 25

What is tachyphylaxis

Answer 25

Acute acquired tolerance | Ephedrine

Question 26

What are some pharmacokinetic mechanisms

Answer 26

Altered absorption of the drug Enzyme induction (increased metabolism of the drug) Increased active excretion of the drug

Question 27

What are some pharmacodynamic mechanisms?

Answer 27

Desensitization (receptor down-regulation) Loss of receptor Exhaustion of mediator

Question 28

Route of administration affects the drug. How?

Answer 28

IV- fastest onset short duration PO- slow onset longer duration Lidocaine- IV- antiarrhythmic Locally- local anesthetic

Question 29

Food and drugs

Answer 29

Absorption rate is typically slower with food/fluid

Question 30

CNS stimulants, when do you give them?

Answer 30

More effective during the day | Circadian effects

Question 31

CNS depressants when do you give them

Answer 31

More effective at night | Circadian

Question 32

What is cumulative

Answer 32

Rate of elimination is slower than absorption Digitalis Phenylbutazone Thiopental

Question 33

Beneficial drug on drug effects

Answer 33

Trimethoprim and sulfonamide | ACE inhibitor and thiazides diuretic

Question 34

Detrimental DRug on drug reactions

Answer 34

Aminoglycoside and muscle relaxant (and a lot of others as well) Chloramphenicol and phenobarbital

Question 35

What is summation

Answer 35

Drug A+ Drug B= A+B

Question 36

What is synergism

Answer 36

Drug A + Drug B > A+B

Question 37

What is antagonism

Answer 37

Drug A+ Drug B

Question 38

What is chemical antagonism

Answer 38

Drugs react chemically to inactivate each other. | Tetracyclines and calcium

Question 39

Physiological antagonism

Answer 39

Drugs that work in different ways and have opposing effects that cancel each other out.

Question 40

Pharmacokinetic antagonism

Answer 40

One drug reduces the concentration of the other at its site of action by interfering with its ADME process.

Question 41

Receptor antagonism

Answer 41

One drug binds to a receptor and prevents the other drug from having its normal activity at that receptor.

Question 42

What is a pharmacokinetic drug on drug reaction?

Answer 42

Absorption - one drug can inhibit the absorption of another drug (SQ lidocaine and epi) - one drug can enhance the absorption of another (topical DMSO & griseofulvin) Distribution -binding site competition on plasma protein (warfarin and phenylbutazone)

Question 43

What are some enzyme inducers?

Answer 43

Phenobarbital, bute, rifampin, griseofulvin, kale

Question 44

What are some enzyme inhibitors?

Answer 44

Chloramphenicol, cimetidine, ketoconazole, grapefruit

Question 45

What are the factors modifying excretion?

Answer 45

Competition for carrier molecules (probenecid and penicillin) Changes in urine pH Acidic urine= inc excretion of weak bases Alkaline urine= inc excretion of weak acids

Question 46

What's an example of temperature modifying drugs?

Answer 46

At 122oF the solubility of procaine increases in Pen G procaine preparations. Don't leave in pickup on a hot day.

Question 47

How does oxygen effect drugs?

Answer 47

Decreased ambient oxygen may worsen respiratory depression induced by pentobarbital.

Question 48

Why is humidity important?

Answer 48

Reconstituted drugs have varying half lives due to humidity. Amoxicillin

Question 49

Why is light important

Answer 49

Some drugs react to light

Question 50

Why is important to know what the drug can bind to?

Answer 50

Some drugs bind to different surfaces.