Tortoise / Turtle: Ivermectin causes fatal toxicosis in chelonians at doses other reptiles tolerateChelonians are far more sensitive than lizards and snakes: doses routine elsewhere in reptile practice have produced paralysis and death in turtles and tortoises. Do not use ivermectin in chelonians; use fenbendazole or another alternative. (The cited study did find 0.05 mg/kg IM tolerated in red-footed tortoises when not repeated inside 7 days, so the hazard is dose- and interval-dependent rather than absolute — but that margin is far too narrow to work to in a clinical setting.)
Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.
Ivermectin is dosed at 0.2 mg/kg SC q14d in ball pythons, per Klaphake E, Gibbons PM, Sladky KK, et al. Reptiles. In: Carpenter JW, eds. Exotic Animal Formulary, 5th ed., Elsevier, St. Louis, MO; 2018:81-166. / 127. Flach EJ, Riley J, Mutlow AG, et al. Pentastomiasis in Bosc’s monitor lizards (Varanus exanthematicus) caused by an undescribed Sambonia species. J Zoo Wildl Med. 2000;31:91-95. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.227 (2026-08-01).. Verify against current literature before clinical use.
Potentiates glutamate-gated chloride channels in invertebrate nerve and muscle cells, causing paralysis and death of parasites.
Side effects & warnings
TOXIC to MDR1-mutant dogs (Collies, Shelties, Aussies) at elevated doses. DO NOT use in chelonians (turtles/tortoises). Narrow safety margin in some species. Test MDR1 status before use in herding breeds.
Species with Ivermectin dosing data (33 dose rules)
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
Backed by 23 published sources
· Bailey TA, Apo MM. Pharmaceutics commonly used in avian medicine. In: Samour J, eds. Avian Medicine, 3rd ed., Mosby Elsevier, Edinburgh, Scotland; 2016:637-678. / 159. Formulary. In: Chitty J, Lierz M, eds. BSAVA Manual of Raptors, Pigeons and Passerine Birds; British Small Animal Veterinary Association, Gloucester, UK; 2008:384-390. doi:10.1016/b978-0-7234-3832-8.00023-7 — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.435 (2026-08-01).
· Bailey TA, Apo MM. Pharmaceutics commonly used in avian medicine. In: Samour J, eds. Avian Medicine, 3rd ed., Mosby Elsevier, Edinburgh, Scotland; 2016:637-678. / 873. Smith JA. Passeriformes (songbirds, perching birds). In: Miller RE, Fowler ME, eds. Fowler’s Zoo and Wildlife Medicine. 2015;Vol 8, Elsevier, St. Louis, MO, 236-246. doi:10.1016/b978-0-7234-3832-8.00023-7 — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.435 (2026-08-01).
· Carpenter's Exotic Animal Formulary, 6th Ed
Sample dosing (2 of 33 cited rules)
A dog/cat sample is shown here. Cited dosing for all 20 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
Mueller RS, Bensignor E, Ferrer L, et al. Treatment of demodicosis in dogs: 2011 clinical practice guidelines. Vet Dermatol. 2012;23(2):86-96, e20-21. / 50. Waisglass S. Demodicosis update--some considerations to increase your success rate. Presented at: WVC; 2009. doi:10.1111/j.1365-3164.2011.01026.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
Upgrade to Pro or Student to unlock the full dose ranges and frequency for every species. The drug's mechanism, warnings, indications, and cited sources are free to read.
Doss G, Carpenter J, et al. African pygmy hedgehogs. In: Quesenberry K, OrcuttC, Mans C, et al. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:401-415.; Heatley J. Hedgehogs. In: Mitchell MA, Tully TN Jr., eds. Manual of Exotic Pet Practice; Saunders/Elsevier, St. Louis, MO; 2009:433-455.; Morrisey JK, Carpenter JW, et al. Formulary. In: Quesenberry Q, OrcuttC, Mans C, et al. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.737 (2026-08-01).
· Eqvalan® Paste 1.87% [Product Label]. Merial; 2008. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
· FARAD Withdrawal Guidelines
· Heartgard® Tablets [Package Insert]. Merial; 2015. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.738 (2026-08-01).
· Hillyer EV, Brown SA. Ferrets. In: Birchard SJ, Sherding RG, eds. Saunders Manual of Small Animal Practice; WB Saunders, Philadelphia, PA; 1994:1317-1344. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.937 (2026-08-01).
· Ivomec Sheep Drench Dewormer [Product Insert]. Merial — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
· Ivomec® 1% Injection for Cattle and Swine [Product Label]. Merial; 2010. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
· Klaphake E, Gibbons PM, Sladky KK, et al. Reptiles. In: Carpenter JW, eds. Exotic Animal Formulary, 5th ed., Elsevier, St. Louis, MO; 2018:81-166. / 127. Flach EJ, Riley J, Mutlow AG, et al. Pentastomiasis in Bosc’s monitor lizards (Varanus exanthematicus) caused by an undescribed Sambonia species. J Zoo Wildl Med. 2000;31:91-95. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.227 (2026-08-01).
· Koch S, Torres S, Plumb DC. Small Animal Dermatology Drug Handbook. Wiley-Blackwell; 2012. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
· Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.777 (2026-08-01).
· Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015.; Eshar D, Bdolah-Abram T. Comparison of efficacy, safety, and convenience of selamectin versus ivermectin for treatment of Trixacarus caviae mange in pet guinea pigs (Cavia porcellus). J Am Vet Med Assoc. 2012;241:1056-1058. doi:10.2460/javma.241.8.1056 — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.777 (2026-08-01).
· Miller, W.H., Griffin, C.E., & Campbell, K.L. (2013f) Parasitic skin disease. In: Muller and Kirk's Small Animal Dermatology (eds. Miller, W.H., Griffin, C.E., & Campbell, K.L.), 7th ed., pp. 284-342. St. Louis, MO: Elsevier. — Verified against Veterinary Ophthalmology (Gelatt), 6th Ed, p.1782 (2026-08-01).
· Morrisey JK, Carpenter JW, et al. Formulary. In: Quesenberry KE, OrcuttCJ, Mans C, et al. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. / 15. Johnson R, Hemsley S. Gliders and possums. In: Vogelnest L, Woods R, eds. Medicine of Australian Mammals; CSIRO Publishing, Clayton South, Vic; 2008:395-437. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.706 (2026-08-01).
· Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.777 (2026-08-01).
· Mueller RS, Bensignor E, Ferrer L, et al. Treatment of demodicosis in dogs: 2011 clinical practice guidelines. Vet Dermatol. 2012;23(2):86-96, e20-21. / 50. Waisglass S. Demodicosis update--some considerations to increase your success rate. Presented at: WVC; 2009. doi:10.1111/j.1365-3164.2011.01026.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.739 (2026-08-01).
· Plumb DC. Plumb’s Veterinary Drug Handbook, 9th ed., Wiley Blackwell, Ames, IA; 2018. (traced through to Plumb’s 10thttp.740 ref 75: Ivey E, Morrisey J. Therapeutics for rabbits. Vet Clin North Am Exot Anim Pract. 2000;3(1):183-216.) — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.850 (2026-08-01).