Introduction

Name

• Doramectin.

Class of drug

• A semisynthetic member of the avermectin class, structurally similar to abamectin and ivermectin.
• An ecto- and endoparasiticide.

Description

Chemical name

• 25-cyclohexyl-5-O-demethyl-25-de(l-methylpropyl)avermectin A1a.

Molecular formula

• C₅₀H₇₄O₁₄.

Molecular weight

• 899.1 g/mol.

Physical properties

• Solution licensed for injection for cattle and sheep is clear, colorless, to pale yellow oily solution for parenteral administration.

Storage requirements

• Do not store above 30°C/86°F.
• Do not freeze.
• Do not refrigerate.
• Protect from direct sunlight.

Uses

Indications

• Doramectin is not licensed for use in the rabbit, but several publications discuss the use of doramectin for mites and ticks in rabbits.

Treatment of Psoroptes cuniculi mites

• Drugs shown to be effective against Psoroptes cuniculi Psoroptes cuniculi are ivermectin Ivermectin, selamectin Selamectin, moxidectin Moxidectin and doramectin.
• In one study, rabbits with Psoroptes infestation that were treated subcutaneously with doramectin at a single dose of 200 μg/kg BW showed a very low therapeutic effect, although there was significant improvement when the dose was doubled to 400 μg/kg BW, with the number of mites counted decreasing significantly. Other agents were more valuable, showing that ivermectin Ivermectin spot-on applied locally on infested ears proved to be more effective against P. cuniculi than doramectin administered via the SC route.

Treatment of sarcoptic mange

• In one study, five Angora rabbits naturally infested with Sarcoptes scabiei Sarcoptes scabiei first received two subcutaneous injections 10 days apart of moxidectin 1% injectable solution at a dosage of 0.2 mg/kg BW:
  • This resulted in clinical improvement initially, but on days 10 and 35 post-initial treatment live mites were observed in skin scrapings.
  • Doramectin 1% was then administered via SC injections 10 days apart and led to complete resolution of clinical signs and parasitological cure in all 5 rabbits.
• In another study, 14 New Zealand rabbits with Sarcoptes scabiei Sarcoptes scabiei infestation were split into three groups: those with low, medium and high intensity of infestation:
  • Within these 3 groups, the rabbits were divided again, some being treated with ivermectin, and the others given doramectin using the same dose and time intervals.
  • By day 28 after starting the treatment, the rabbits with low and medium intensity had recovered with administration of both doramectin and ivermectin.
  • In the high intensity infestation groups, both drugs were efficacious microscopically and macroscopically, however ivermectin had a more rapid effect than doramectin.

Treatment of Leporacarus gibbus

• One study evaluated the efficacy of a single oral dose of doramectin in the control of Psoroptes ovis and Leporacarus gibbus Leporacarus gibbus in naturally infested rabbits.
• Sixteen adult rabbits were selected and were put in two experimental groups:
  • The treated group received 200 μg/kg of oral doramectin (control group received the same volume of saline solution).
  • An efficacy of 75% and 87.5% was observed for L. gibbus in days +3 and +7 after treatment. After 14 days post treatment there was 100% efficacy.
  • An efficacy of 100% for the control of P. ovis was observed after 7 days.
  • No adverse effects were observed in any of the rabbits administered doramectin.

Treatment/control of ticks

• In one study, the efficacy of a single subcutaneous injection of an avermectin (ivermectin, doramectin, or abamectin) as a treatment for experimental infestation with nymphal and adult Haemaphysalis longicornis was assessed in 24 New Zealand White rabbits.
• Rabbits were injected with commercial injectable formulations of the avermectin (1%) assigned to their treatment group, at a single dose of 200 μg/kg via the SC route.
• Nymphs and female ticks had significantly reduced weight, nymphs had reduced molting success rates, and female ticks had inhibited ovary development.
• Of the three treatment agents, doramectin was most effective in reducing the weight of nymphs (weight was reduced by 80%) and females (by 97.3%).
• Both doramectin and abamectin were effective in inhibiting the development of female ticks’ ovaries (by 46%).

Administration

Pharmacokinetics

Precautions

Interactions

with other drugs

• None known.

Adverse Reactions

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Elhawary N M, Sorour S S G H, El-Abasy M A, Bazh E K & Sultan K (2017) A trial of doramectin injection and ivermectin spot-on for treatment of rabbits artificially infested with the ear mite "Psoroptes cuniculi". Pol J Vet Sci 20 (3), 521-525 PubMed.
• Santos R R D, Coelho C N, Nunes T A et al (2017) Efficacy of oral doramectin as treatment for Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits. Pesquisa Veterinária Brasileira 37 (1), 47-51 Scielo (pdf download).
• Bulliot C, Mentre V, Marginac G, Polock B & Chermette R (2013) A case of atypical psoroptic mange in a domestic rabbit. J Exotic Pet Med 22 (4), 400-404 VetMedResource.
• Doan H T T, Noh J H, Kim Y H, Yoo M S et al (2013) The efficacy of avermectins (ivermectin, doramectin and abamectin) as treatments for infestation with the tick Haemaphysalis longicornis on rabbits in Korea. Vet Parasitol 198 (3-4), 406-409 PubMed.
• Gokbulut C, Biligili A, Kart A & Turgut C (2010) Plasma dispositions of ivermectin, doramectin and moxidectin following subcutaneous administration in rabbits. Lab Anim 44 (2), 138-142 PubMed.
• Kaya D, Inceboz T & Kolatan E et al (2010) Comparison of efficacy of ivermectin and doramectin against mange mite (Sarcoptes scabiei) in naturally infested rabbits in Turkey. Vet Ital 46 (1), 51-56 PubMed.
• Bian Y, Yang G, Wang T & Yan H et al (2009) Haemaphysalis concinna (Acari: Ixodida): Persistent efficacy of doramectin in rabbits under laboratory conditions. Entomol Res 39 (2), 119-122 WileyOnline.
• Li N, Jiang H, Li J, Wang Z et al (2009) Pharmacokinetics of doramectin in rabbits after subcutaneous administration. J Vet Pharmacol Therapeut 32 (4), 397-399 WileyOnline.
• Shen J, Li N, Jiang H, Li J et al (2009) Residue depletion of doramectin in rabbit tissues after SC administration. J Food Prot 72 (10), 2189-2194 PubMed.
• Jiang H, Zhou D, Li H, Xu F, Li C, Shen J, Li X & Ding S (2008) LC-fluorescence detection of abamectin, ivermectin, doramectin, and eprinomectin in rabbit feces. Chromatographia 68 (3), 259-262 AGRIS.
• Kanbur M, Atalay O, Ica A, Eraslan G & Cam Y (2008) The curative and antioxidative efficiency of doramectin and doramectin+vitamin AD3E treatment on Psoroptes cuniculi infestation in rabbits. Res Vet Sci 85 (2), 291-293 PubMed.
• Voyvoda H, Ulutas B, Eren H, Karagenc T & Bayramli G (2005) Use of doramectin for treatment of sarcoptic mange in five Angora rabbits. Vet Derm 16 (4), 285-288 PubMed. 

Other sources of information

• PubChem (online) Compound Summary Doramectin. In: National Center for Biotechnology Information. Website: pubchem.ncbi.nlm.nih.gov.