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Pharmaceutical Care of Select Avians & Exotics: Practitioner Summary

 

Avian & Exotic Animal Care

 

Pharmacotherapeutic Considerations:

  • Very few FDA-approved products
  • Minimal pharmacokinetics/pharmacodynamic data
  • Pharmacoeconomics
  • Strong human-animal bond
  • May be companions and also food animals
  • Mostly prey species – usually arrive very sick
  • Tend to have a very low body weight
  • Typically have long life spans

 

Avian

  • Life span varies per species (ex. Finches 4-5 years vs. Macaws 20-100 years)
  • Health is highly dependent on nutrition, husbandry and enrichment
    • Enrichment “toys” and foods can be used as drug delivery tools
  • More similar to reptiles than mammals
  • Renal-portal system (Avian and Reptile)
    • Drugs that are injected into the rear circulation are highly likely to get excreted or processed by the kidneys before entering systemic circulation
    • Caution with nephrotoxic drugs – should be administered in the top half of the body
  • Drug administration
    • Oral
      • Administer in food, water or directly into crop (tablets/capsules, solutions/suspensions)
    • Intraosseous injections
      • Bones are highly vascularized in birds (50% enters circulation in 30 seconds)
      • Hypertonic/strong alkaline drugs must be diluted
      • Volume limitations (1-2 mL in small birds / 8-25mL in large birds)
      • More rapid than IV, SQ, and PO administration
    • Nebulization
      • Usually used for respiratory tract or skin infections
      • Need oxygen source and enclosed chamber
      • Drug considerations
  • Infectious organisms
    • Chlamydia psittaci – ocular, nasal or conjunctival irritation and discharge
      • Treatment considerations: doxycycline has variable aqueous stability
    • Mycobacterium avium and genavense
      • Chronic progression – anorexia, weight loss, depression, and diarrhea
      • Treatment is controversial
    • Fungal (aspergillosis and candida)
      • Vague and nonspecific signs
      • Treatment: amphotericin B, terbinafine, nystatin, fluconazole, voriconazole
  • Nutrition, husbandry, and behavior
    • Hypovitaminosis A (vitamin A deficiency)
    • Egg binding or chronic egg laying
      • Behavioral – obesity or sedentary
    • Feather plucking
      • Lack of enrichment/socialization
    • Obesity

 

Reptilians

  • Very similar to avian
  • Tremendous variation in temperature, diet, nutritional and physiologic requirements
  • Drug administration
    • Topical and oral (usually not very effective due to keratinized skin and highly variable GI transit)
    • Subcutaneous / intravenous
      • Difficult – veins collapse, renal-portal system considerations
    • Intramuscular (most common)

 

Avian and Reptile

  • Drug adverse effects
    • Potentiated sulfonamides – emesis, crop stasis
    • Aminoglycosides – gentamicin more nephrotoxic than amikacin
    • Itraconazole – more hepato/gastro toxic in African Grey parrots; compounded formulations from bulk ingredients are unstable and have reduced bioavailability
    • Ivermectin – neurotoxic when administered systemically; contraindicated in chelonians (turtles, tortoises, and terrapins)
  • Compounding considerations
    • Caution with oral suspension in oil (risk of aspiration)
    • Injections with ingredients that may be nephrotoxic should be avoided
    • Medications for food and water may not be consumed at a regular rate when patients are ill
    • Seed/grain eating birds have a diet high in calcium which can interact with the oral bioavailability of tetracyclines
    • Be careful when using drug-coated feed or pellets – some birds remove the outer shell before consuming

 

Small Mammals: Rodents

  • Monogastric, herbivores, or omnivores
  • Coprophagic – consume their own feces
  • All rodents
    • Antibiotic-induced enterocolitis
    • Acceptable antibiotics for rodents
      • Chloramphenicol, metronidazole, TET, TMS, FQ, AG
    • Contraindicated:
      • Penicillins, cephalosporins, vancomycin, erythromycin, clindamycin
  • Hamsters/Guinea Pigs
    • Avoid drugs that cause enterotoxemia – beta-lactams, clindamycin, erythromycin, tetracycline, bacitracin, vancomycin and lincomycin
  • Compounding considerations
    • Most readily accept sweet flavors
    • Coporphagia may change drug and formulation selection

 

Rabbits

  • Herbivores – sensitive GI flora
  • Coprophagic
  • Unable to vomit – no bubble or gas producing oral products
  • Adverse events and compounding considerations
    • Be cautious with antibiotic therapy and watch exposure to preservatives in compounded products
    • Corticosteroids are contraindicated – immunosuppression / liver toxicity
    • Fipronil (active ingredient in Frontline) should never be used in rabbits

 

Ferrets

  • Obligate carnivores
  • Low capacity for xenobiotic conversion – slow glucuronide metabolism
    • Similar to felines
  • Slow digestive tract
  • Affinity for rubbery textures for chewing
  • Insulinoma risks – avoid high carbohydrate (formulations containing sugar)