cardiotoxicity

Question 1

Ld 50 of Caffeine, theophylline and
theobromine - methylxanthines in dogs

Answer 1

300mg/kg

Question 2

LD50 due to Caffeine, theophylline and
theobromine - methylxanthines in cats

Answer 2

200mg/kg

Question 3

cardiac dearangements due to macrolids

Answer 3

• ECG changes (QT prolongation)
• Myocardial damage
• Generates oxidative stress
• Also seen with fluoroquinolones and ketolides
• Prolongation of cardiac repolarisation and sudden death syndrome
  
  • Ventricle fibrillation
  • Prevalence in animals (dogs) is not known
  • Cardiotoxicity of cytostatic agents

Question 4

discuss pathogenesis of macrolids in cardiotoxicity

Answer 4

• HERG block leading to
• increased action potential duration, EADs and heterogenecity of repolirization
• leading to qt prolongation

Question 5

explain how monensim works in cows

Answer 5

• it is a cocciciostants
• Slow release devices (rumen bolus) or in feed medication
• Carboxylic ionophores exert antimicrobial activity (grampositivebacteria) - microbiological NOEL
• In the rumen:
  
  • Reduction of gram-positive bacteria and acetic acid
  • and butyric acid producing bacteria
  • Promotion of propionic acid producing gram negative bacteria
• leading to Increased feed utility - treatment of rumen acidosis and ketosis

Question 6

Carboxylic ionophores: causing cellular alkolosis

describe their mechanism ie movement of electolytes

Answer 6

monensin

NA into the cell

K and H out of cell

Question 7

Carboxylic ionophores: causing cellular acidity

describe their mechanism ie movement of electolytes

Answer 7

• Salimomycin
• narasin
• k out
• h in

Question 8

mechanism for inophores

Answer 8

increase influx of ca into the cell

leading to increased mm necrosis

Question 9

cs of coccidostatics

Answer 9

• In several animal species:
  
  • anorexia, diarrhoea, depression,
  • hypoactivity/reluctance to move,
  • dyspnea, leg weakness, ataxia
  • and recumbency

Question 10

tx for coccidiostatics

Answer 10

Treatment:

• no antidote
• Feedchange,
• adherence to species restrictions

Question 11

histological lesion of monensin intoxication in horse

Answer 11

• Infiltration of neutrophils and
• lymphocytes in necrotic muscle fibers
• Mitochondrial swelling/disrupted christae.
• Myelin figures and lipid vesicles
• Cellular (myocyte) necrosis. Ruptured fibres,
• hypercontraction bundles
• Inflammatory reaction: macrophage invasion
• Tissue fibrosis - chronic heart failure

Question 12

clinical signs of ionophore
intoxications

Answer 12

• Anorexia
• Diarrhea (monensin and
• lasalocid)
• Depression
• Hypo-activity
• Reduced feed conversion
• Dyspnea
• Leg weakness
• Ataxia, recumbency
• Growth depression
• Drop in egg production

Question 13

which lesions do u see in horses due to ionophore/coccidostats

Answer 13

cardiac lesions

Question 14

which animal show the most muscle lesions due to ionophores

Answer 14

Muscle lesions: sheep > pigs > dogs > cattle > horses

Question 15

cs of monensin in humans

Answer 15

• they take them to increase mm mass
• Sickness, nausea, abdominal pain,
  myoglobinuria, weakness, severe muscle pain,
  tachycardia
• Death after 6 days: acute rhabdomyolysis & renal
  failure

Question 16

lab findings for monensia

Answer 16

• increased mm enzyms
• CK 233.200 U/L (ref range < 80U/L)
• LDH 13.100 U/L (ref range 240-480 U/L)
• Creatinine 2,0 mg/dL (ref range 0,2-1,4 mg/dL)

Question 17

which drugs prevents monensin demythylation through drug to drug interaction

Answer 17

drugs that inhibit cyp3A

they will inhibit monensin as well

and the drug will

Question 18

which drugs reduce tolerance for monencin

Answer 18

• tiamulin,
  macrolides
• and fluoroquinolones

Question 19

this drug cause death in chicken when combined with monencin

Answer 19

• tiamulin and monensin

Question 20

this drug cause death in pigs when combined with monencin

Answer 20

valnemulin and monensin