Ionophores Flashcards
Use of ionophores
- anticoccidial in production animals
- growth promoter feed additive for cattle
- reduction of bloat and rumen acidosis
- prevent tryptophan induced atypical bovine pulmonary emphysema
Monensin is used to
improve efficiency of milk production
Solubility of ionophores
- slightly soluble in water
- soluble in organic solvents and oils
How do ionophores get across membranes
they form lipid soluble complexes with cations that are easily transported across
Most common source of ionphore toxicosis
- Monensin
- usually too much in the feed for the specific species
- sometimes used to poison horses
Most to least sensitive species
Equines –> cattle –> poultry
What will increase toxicosis
- concurrent admin of other drugs (mostly antibacterials and antifungals)
Toxicokinetics
- ruminants= absorb 50%
- monogastrics= absorb MOST of it
- distributed through the body
- not high levels in any specific part of the body
Metabolism of ionophores
- rapid
- P-450 oxidative demethylation enzymes in the liver
- excreted in bile
- slower in horses
MOA of ionophores
- fuck with transmembrane electrochemical gradients
- targets mitochondria in energetic tissues
- increases intracellular sodium and calcium
- cell death due to loss of homeostasis
- ROS production
What cells are most affected by the ionophores
- neurons, myocardium, skeletal muscles, and smooth muscle
- messed up calcium messes everything up
Clinical signs in horses
- rapid onset
- anorexia, colic
- sweating, depression, incoordination
- hyperventilation
- tachycardia, arrhythmias, death
Clinical signs in cattle
- anorexia, diarrhea
- depression, ataxia
- labored breathing
- death
Clinical signs in poultry
- anorexia, diarrhea
- ataxia
- resting on the knees with wings and leg directed outward
- decreased egg production
clinical signs in dogs
- ataxia, muscle weakness of HIND limbs
- respiratory paralysis
- dyuria
- constipation
- depression
Lesions with inonphore toxicosis
- pale cardiac muscles in horses with white streaks of necrosis
- pale skeletal muscles in sheep, pigs and dogs
- both skeletal and cardiac in cattle and poultry
Chemical analysis for ionophores
- detect ppb levels
- Best to sample feed
- then sample GI contents, liver and feces
Clin path for ionophore toxicosis
- elevated CPK, AST, LDH, ALP, PCV
- decreased serum Ca and K in first 12 hrs
- No change in sodium
Treatment for ionophore
- no specific antidote
- remove medicated feed
- Detox with activated charcoal, mineral oil or saline cathartics
Symptomatic treatment
- IV fluids and electrolytes
- potassium
- monitor cardiac function
- horses should not be ridden for MONTHS
Prognosis for horses
- they can survive sometimes but will never be great at their job
