What is the recommended dosage of isoxazolines (e.g. sarolaner (Simparica)) in camelids (e.g. llamas and alpacas)?

Isoxazoline Dosage in Camelids

Due to the lack of specific guidelines for isoxazoline use in camelids, an empirical dosage of 1 mg/kg of sarolaner (Simparica) administered orally is recommended for llamas and alpacas based on extrapolation from other species and pharmacokinetic principles.

Background on Camelids and Medication Use

Camelids (llamas and alpacas) are classified as food-producing animals, but most veterinary medications are not specifically licensed for these species 1. This necessitates off-label use of antiparasitic drugs, which requires careful consideration of:

• Unique physiological characteristics of camelids
• Different pharmacokinetic profiles compared to other ruminants
• Special considerations for drug administration routes

Dosage Recommendation for Isoxazolines

While there are no specific guidelines for isoxazoline use in camelids, the dosage can be extrapolated based on:

1. Route of Administration: Oral administration is preferred for isoxazolines in camelids

   • Pour-on formulations are largely ineffective due to unique features of camelid skin and hair 1
   • Oral administration has shown good bioavailability in camelids for other medications 2

2. Dosage: 1 mg/kg of sarolaner (Simparica) orally

   • Based on effective dosages used in cats (0.88-1.19 mg/kg) 3
   • Considering that camelids have shown variable but often good oral bioavailability for other drugs 2

3. Frequency: Monthly administration

   • Based on the duration of efficacy observed in other species 3
   • May require adjustment based on clinical response

Pharmacokinetic Considerations

Camelids have unique pharmacokinetic profiles that affect drug dosing:

• Studies on oral meloxicam in llamas showed 76% bioavailability, indicating good gastrointestinal absorption 2
• Elimination half-life for some drugs may be prolonged in camelids compared to other ruminants 4
• Drug metabolism may differ from other species, requiring careful monitoring for efficacy and toxicity

Monitoring and Precautions

When administering isoxazolines to camelids:

• Monitor for efficacy against target parasites

• Watch for potential adverse effects:

  • Neurological signs (tremors, ataxia)
  • Gastrointestinal disturbances
  • Changes in behavior or appetite

• Adjust dosage based on clinical response and body weight

• Consider consulting with a veterinarian experienced in camelid medicine

Alternative Antiparasitic Options

If isoxazolines are not available or appropriate, consider these alternatives with established use in camelids:

• Fenbendazole: 5-10 mg/kg orally 4
• Ivermectin: 200 μg/kg for parasitic infections 5
• Mebendazole: For various parasitic infections 5

Important Caveats

• No isoxazoline products are currently FDA-approved specifically for camelids
• Treatment represents off-label use requiring veterinary prescription
• Individual response may vary, necessitating clinical monitoring
• Weight estimation should be accurate to avoid under or overdosing

The recommendation for sarolaner dosing is based on extrapolation from other species and pharmacokinetic principles in the absence of specific camelid studies on isoxazolines.