ISSN 2398-2950      

Spinosad

ffelis
Contributor(s):

Linda Horspool

Synonym(s): Comfortis®, Trifexis®


Introduction

Name

  • IUPAC
  • CAS

Class of drug

  • Spinosyn - mixture of spinosyns A and D.
  • Macrolides (non-antibacterial) containing a unique tetracyclic ring system with two sugar derivatives (forosamine and rhamnose sugars) attached through ether linkages.

Description

Chemical name

  • Spinosyn A: 2-((6-deoxy-2,3,4-tri-O-methyl-a-L- mannopyranosyl)oxy)-13-(((5- dimethylamino)tetrahydro-6-methyl- 2H-pyran-2-yl)oxy)-9-ethyl- 2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16 b-tetradecahydro-14-methyl-1H-as- indaceno(3,2-d)oxacyclododecin-7,15- dione.
  • Spinosyn D: 2-((6-deoxy-2,3,4-tri-O-methyl-a-L- mannopyranosyl)oxy)-13-(((5- dimethylamino)tetrahydro-6-methyl- 2H-pyran-2-yl)oxy)-9-ethyl- 2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16 b-tetradecahydro-4,14-dimethyl-1H-as- indaceno(3,2-d)oxacyclododecin-7,15- dione.

Molecular formula

  • Spinosyn A C42H67NO16.
  • Spinosyn D C41H65NO16.

Molecular weight

  • Spinosyn A 731.98.
  • Spinosyn D 746.00.

Physical properties

 
Property Spinosyn A Spinosyn D
Water Solubility (at 25°C, pH7) 235 ppm 0.332 ppm
Octanol-water Partition Coefficient (log P, pH7) 4.0 4.5
Photolysis half-life 23 hours 20 hours
 
  • Product as packaged for sale:
    • Chewable tablets.
    • Flavored with artificial beef flavor.
    • Unscored tan to brown, or speckled, round, flat, bevelled edge tablets, plain on one side and debossed on the other.

Storage requirements

  • Product as packaged for sale:
    • Room temperature (between 9 and 25 °C).
    • Keep the blister pack in the outer carton.
 

Uses

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Indications

  • Ectoparasiticide. Insecticide. Adulticide.
  • Treatment of flea infestations (Ctenocephalides felis  Ctenocephalides felis  ) and prevention of re-infestation for up to 4 weeks.
  • Can be used as part of a treatment strategy for the control of flea-allergy dermatitis (FAD)   Flea bite hypersensitivity  .

Administration

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Pharmacokinetics

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Precautions

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Interactions

with other drugs

  • Spinosad has been shown to be a substrate for P-glycoprotein (PgP). Spinosad could therefore interact with other PgP-substrates (for example, digoxin   Digoxin  , doxorubicin   Doxorubicin  ). This could lead to enhanced adverse reactions and/or compromised efficacy.
  • Concomitant use of spinosad with extra-label high dose ivermectin   Ivermectin   has led to some dogs experiencing trembling/twitching, salivation/drooling, seizures, ataxia, mydriasis, blindness and disorientation.  
  • Spinosad has a different binding site from other nicotinic or GABAergic insecticides, such as neonicotinides (imidacloprid   Imidacloprid   or nitenpyram), phenylpyrazoles (fipronil   Fipronil  ), milbemycins   Milbemycin oxime  , avermectins (eg selamectin   Selamectin  ) or cyclodienes.  

Adverse Reactions

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Paarlberg T E, Wiseman S, Trout C M, Kee E A, Snyder D E (2013)Safety and efficacy of spinosad chewable tablets for treatment of flea infestations of cats.J Am Vet Med Assoc242, 1092-1098PubMed.
  • Snyder D E, Meyer K A, Wiseman S, Trout C M, Young D R (2013)Speed of kill efficacy and efficacy of flavored spinosad tablets administered orally to cats in a simulated home environment for the treatment and prevention of cat flea (Ctenocephalides felis) infestations.Vet Parasitol196, 492-496PubMed.

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