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Anatomy & Physiology Considerations: Practitioner Summary

  • Pharmacists are the only healthcare professional legally allowed to provide for ALL species.

 

Anatomy Considerations

Feline

Canine
  • Horizontal orientation
  • Large SubQ space near scruff of neck (great location for SubQ injections)
  • Average weight = 5kg
  • Pinnae = inner hairless part of the ear
  • Lack Tas1r2 and Tas1r3 – cannot taste sweet flavors
  • Horizontal orientation
  • Large SubQ space near scruff of neck (great location for SubQ injections)
  • Elongated ear canal
  • Dolichocephalic vs. Brachycephalic
  • 50x more olfactory neurons than humans

Pharmacokinetics

Feline

Canine
  • Acidic gastric pH
  • GI transit time = ~12 hours
  • Species-wide defect in ABCG2 transporter (efflux pump)
  • Glucuronidation deficient (acetaminophen toxicity concern)
  • Poor glycine conjugation
  • Poor thiopurine methyltransferase activity
  • GFR is 3mL/kg/min (2x faster than humans)
  • Acidic gastric pH</li
  • GI transit time = ~12 hours
  • ABC1 gene mutation
  • Acetylation deficiency – absence of NAT genes
  • CYP enzymes may or may not have the same name and may or may not share substrate specificity
  • GFR is 4mL/kg/min (2.5x faster than humans)

 

  • Acetaminophen toxicity in felines is a serious concern since acetaminophen is so commonly used in human medicine. Since felines lack the capability to glucoronidate, acetaminophen produces a metabolite that produces methemoglobinemia. As a pharmacist, NEVER RECOMMEND USING ANY ACETAMINOPHEN PRODUCT IN A FELINE PATIENT.

 

  • ABCB1 Gene Mutation in Canines:
    • Genetic modification that causes deficiency in p-glycoprotein (P-gp) which is responsible for exporting substances outside the cell membrane of tissues to be eliminated from the body.
    • Mostly affects herding canine breeds – Collie, Long-Haired Whippet, Silken Windhound, Australian Shepherd, McNab, Shetland Sheepdog
    • Drugs that are affected by this mutation include: acepromazine, butorphanol, doxorubicin, ivermectin, loperamide, vinka alkaloids

 

  • Sulfamethoxazole and trimethoprim (known as Bactrim in human medicine) is commonly called TMS in veterinary medicine.