Principles of Drug Toxicity Flashcards Preview

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Flashcards in Principles of Drug Toxicity Deck (19)
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1
Q

Therapeutic index =

A
Effective dose (50%)/ Toxic dose (50%)
Risk Benefit Analysis done before drug is authorized
2
Q

Why do we see drug toxicity in veterinary patients?

A

use of drugs in untested species
mistakes in dose calculation
multiple drugs in use

3
Q

adverse drug reactions (ADR) - Type A reactions

A

Predictable from knowledge of mechanism of action of the drug
Beta blockers causing bradycardia
ACE inhibitors causing acute renal failure
Sulphonylurea drugs causing hypoglycaemia

4
Q

adverse drug reactions (ADR) - Type B reactions

A

Not related to the mechanism of action of the drug therapeutically – non/predictable

5
Q

Factors that enhance ADR

A

Physiological Factors - Age, breed, gender
Disease status - Hepatic, renal and cardiovascular
Concomitant use of other drugs

6
Q

differences in physiology in neonates

A

decr gut motility, underdeveloped mucosa + flora
incr total body water
Immature liver enzymes
Decr GFR

7
Q

drug in neonates - Empirical guidelines

A

Avoid if possible
drugs with wide therapeutic indices if possible
formulation that allows accurate dosing
Weigh the animal accurately

8
Q

Examples of toxicities specific to neonates

A

Fluoroquinolones – damage to articular cartilage

Tetracyclines – discolouration of teeth

9
Q

Increased risk of ADRs in geriatrics because

A
Smaller body size
Poor nutritional status
Presence of multiple disease processes
Altered compliance
Age related changes in organ function (e.g. renal function)
10
Q

why does decr renal function incr chance of ADR

A

decr clearance of drugs via the kidneys

11
Q

Monensin toxicity in horses

A

Clinical signs - neuronal, skeletal and cardiac muscle effects of ionophores
susceptibility d/t low first pass metabolism in horses -systemic bioavailability of this drug much higher than in sheep.

12
Q

Pyrethrum insecticide treatment of cats

A

more sensitive to the toxic effects flea products for dogs
d/t ineffective metabolism
hyper-excitability leading to convulsions
incidence of accidental toxicity is high, despite clear labels saying toxic to cats

13
Q

Type A examples - Beta blockers

A

bradycardia

14
Q

Type A examples - ACE inhibitors

A

acute renal failure

15
Q

Type A examples - Sulphonylurea drugs

A

hypoglycaemia

16
Q

idiosyncratic type B reactions - Chloramphenicol

A

aplastic anaemia

17
Q

idiosyncratic type B reactions - Phenylbutazone

A

agranulocytosis

18
Q

idiosyncratic type B reactions - Phenytoin

A

hepatitis

19
Q

Detection of idiosyncratic reactions

A

Less than 1 in 2000 patients
not detected by pre-registration clinical trials
post-licensing surveillence scheme needed