JJK 1 Flashcards
How does drug absorption from the gut of a horse occur?
May occur in 2 phases, separated by 8-12 hours
How do sheep vary from goats or cattle?
They have a higher hepatic microsomal protein content - increase drug metabolism
Usual pH of urine of carnivores
Acidic - 5.5-7
Usual pH of urine of herbivores
Alkaline - 7.2-8.4
What animal has a GFR of 1.62ml/min.kg
Horse - relatively low. May allow for less mass/kg of drug
What animal have GFRs of 1.8-2.4ml/min.kg
Cattle, sheep, pigs
What animals have GFRs of 3.5-4ml/min.kg
Dogs and cats
How does the metabolism of aminoglycosides differ between animals?
Rates are higher in dogs and cats than horses
Do phase 1 reactions take place in all domestic animals
yes
Do phase 2 reactions take place in all domestic animals
no - either defective or absent in certain species
What conjugation reaction is a cat defective in?
Glucuronide synthesis
- deficiency of UDP-glucuranosyl transferase
- present but at a slow rate
- target groups of OH, COOH, NH2, NH, SH
- considerably enhances the potential toxicity of several drugs including NSAIDs
What conjugation reaction is a dog defective in?
Acetylation
- Absent
- Major target group: Ar-NH2
- Unable to acetylate aromatic amines but this does not delay the elimination of these drugs as alternative metabolic pathways compensate
What conjugation reaction is a pig defective in?
Sulfate conjugation
- Present but at a low extent
- Major target groups Ar-OH, Ar-NH2
What is the neonatal period defined at
birth to 1 month
Absorption and disposition of drugs are most unusual during the first 24 hours
How long does the rumen take to develop
8-12 weeks
bioavailability of oral drugs is similar to monogastric species during this period
Characteristic features of neonatal period drug delivery
- increased gut absorption
- decreased binding to plasma proteins
- increased Vd
- Increased permeability of the BBB
- Decreased rate of metabolism and elimination
