A-27 Anthelmintics (benzimidazoles, imidazothiazoles, tetrahydropyrimidines) Flashcards
Must know drugs Benzimidazole
Albendazole
Fenbendazole
Flubendazole
Triclabendazole
Febantel
Must know drugs Imidazothizole
Levamisole
Must know drugs Tetrahydropyrimidine
Pyrantel
Action of antihelmintics
Expel parasite by :
Stunning
Killing
Have a selective toxicity to parasite
Antinemadotals
Against roundworm
Anticestodal
Against tapeworm
Antitrematodals
Against flukes
Types of benzimidazole
Benzimidazole carbamates (halogenated)
Pro Benzimidazole
Mechanism of action of Benzimidazole
Tubular polymerisation inhibition
So inhibition in cell transport & E metabolism
Spectrum of Benzimidazole
AT, AC, AN
Antiparasitic/fungal/viral/tumor effect
Benzimidazole only for liver flukes
Triclabendazole
Resistance of Benzimidazole
Ru: GI roundworm
Swine: oesophagostomum
Eq: strongylus
Ca: blood sucking nematodes
PK : abs of Benzimidazole
Poor in GI ( except Albendazole & oxfendazole) last 6-30 h
Slowed by rumen & eq caecum
Feed decreases activity
Pk: met of Benzimidazole
Rumen acts as drug reservoir
Febantel oxidised to Fenbendazol then Oxfendazole
Pk: excr. Of Benzimidazole
Biliary, both (parent & metabolites) eliminated with faeces
Administration of Benzimidazole
PO relitavely safe
Toxicity of Benzimidazole
Teratogenic
Hepatotoxic, feather/hair loss (prolonged use)
Neurotoxic (large dose)
Specie application of Febantel
Ca
Fe
Species application of Flubendazole
Ca
Fe
Sus
Species application of Mebendazol
Ca
Fe
Eq
Species application of Fenbendazole
Ca
Fe
Eq
Sus
Species application of Albendazole
Ru
Species application of Triclabendazole
Ru, only for liver flukes
Mode of action of imidazothiazoles
nAch receptor agonist —> paralysis
Imidazothiazole spectrum
AN, larvicidal (migrating stage) & adultcidal
Imidazothiazole resistance
Ru: GI nematodes
Cross resistance with Morantel
Pk of Imidazothiazole
A: rapid
Excretion: rapid, urine
Administration route of levamisole
PO
SC in sheep (short WP, 0 days for milk)
Toxicity of levamisole
NARROW TI
Kuvasz dogs are very sensitive
Cats and horses too
Side effects of levamisole
Salivation, tremors, ataxia, urination, defecation , collapse, asphyxia
Antidote in case of Levamisole toxicosis
Atropine
Mechanism of action of tetrahydropyrimidines
Cholinomimetic —> paralysis
Tetrahydropyrimidines spectrum
AN, adult gut worms & larval stages
PK of pyrantel
Abs: Good in Sus & ca
Bad in Ru
Met: rapid
Excr: urine
Pk of Morantel
Abs: good in SI
Met: liver (short WP & 0 milk)
Excr: urine
Species application of pyrantel
Ca
Fe
Eq
PO
Species application of Morantel
Bolus: Cattle
Oral suspension: Sheep
Tetrahydropyrimidines resistance
Migrating larvae
Whipworms (except oxantel)
Toxicity of Tetrahydropyrimidines
Cholinergique signs
Antidote : atropine
Morantel is safer in Ru
