Flashcards in Kumar's Final Review - Anti-Helmenthics - AH Deck (56):
What are the Anti-nematodal (roundworm) drugs?
BZDs, Levamisole, Pyrantel/Morantel, Dichlorvos, Macrocyclic lactones, Piperazine, HW adulticides
What drugs are anti-cestodal (tapeworms)?
Dichlorphen, Resorantel, Praziquantel, Epsiprantel, BZDs
What drugs are anti-trematodal (flukes)?
Bithionol, Nitroxynil, Salicylanilides, Sulfonamides (clorsulon), and BZDs (albendazole and triclabendazole)
Irreversibly binds to nematode Beta-tubulin → inhibition of microtubules
Adverse effects of BZDs?
Contraindicated in pregnancy → teratogenic
Which group of BDZs are also effective against cestodes?
Carbamates: Mebendazole (taenia), oxibendazole, Albendazole, Fenbendazole
What are the two proBZDs?
Albendazole → Netobimin. Fenbendazole → Febantel.
What happens to the sulphoxide in the proBDZs?
They are later converted to sulphoxones
MOA of Imidazothiazoles?
Neuromuscular blockade (never combine)
How are Imidazothiazoles administered?
Oral, parenteral (SC) or topical
Name a Imidazothiazole that is a l-isomer of dl-tetramisole
MOA of Levamisole (2)
1. Ganglionic stimulant and direct cholinergic drug. Binds to nicotinic receptors of nematode parasites → depolarization blockade. 2. immunostimulator (CMI)
Margine of safety for Levamisole?
narrow margin of safety. Safety factor is twice that of Tetramisole.
What increases the toxicity of lavamisole?
simultaneous admin of pyrantel tartrate
What animals should you avoid giving Levamisole to?
Lactating dairy animals
Why do you need to wear gloves when handling Levamisole?
Percutaneous absorption → blood disorders/ fatal agranulocytosis
What drugs are included in Tetrahydropyrimidines group?
Pyrantel and Morantel
Which is safer, pyrantel or morantel?
MOA of Tetrahydropyprimidines?
Depolarization blockade → paralysis of nematode
How are Tetrahydropyprimidines administered?
Oral only → GI nematodes and lungworms
What animals should not be given Organophosphate compounds?
Ill or stressed patients
What can be used to treat pinworms?
Pamoate salt – not soluble → GI
What organophophate can be incorporated into polyvinal pellets?
What Organophophate is effective against Whipworms Trich spp.?
irreversible inhibition of AchE → paralysis of nematodes
MOA of Macrocyclic Lactones?
Binds to Cl- channels → increase in GABA → hyperpolarization → flaccid paralysis of parasite and expulsion
What are the two main categories of Macrocyclic Lactones?
Avermectins and Mibemycins
What are the 5 Avermectins?
Ivermectin, Doramectin, Eprinomectin, (Selamectin, Abametin)
What Avermectin can't be given to collies, aussies or murrah gray cattle?
Which Avermectin has a low milk plasma ratio and can be used in dairy cows?
Which Avermectin can be used in the Tx of screw worms and Myiasis?
Prophylactic against H Ws → micro filaricide
What are the two Mibemycins?
Milbemycin Oxime and Moxidectin
Piperazine class spectrum?
Drugs in the Piperazine class include?
Piperazine and Diethylcarbazine (DEC)
When should you avoid giving Piperazine?
In animals with chronic liver Dz and in heavy ascarid infxns → intestinal impaction or rupture
how is Diethylcarbazine used?
As a prophylactic HW Tx – adult stages of nematode only (no microfilaria)
What needs to be done before Tx with DEC?
Dog should be cleared of adult and larval microfilaria or risk anaphylaxis
Tx timing for DEC?
Restart Tx 4 weeks after the first Tx
What are the two heartworm adulticides?
Thiacetarsamide sodium and Melarsomine
Which HW adulticide is safest and more potent?
Toxicity of Thiacetarsamide Na?
Nephrotoxicity and Hepatotoxicity
Restorantel can be used to treat?
Rumen flukes (parphistomeum) and Moneizia spp. In ruminants
Which anti-cestodal is only used to tx cectodes?
Wide = adult and larval cestodes and trematodes (shistosomes)
Vd of praziquantel?
well absorbed and distributed
MOA of Praziquantel?
Centres on Ca++ ion flux across the surface membranes of the exposed parasite. Adult cestodes –release >of Ca from mm stores. In schistosoma –Ca >is taken up –mm >contraction –paralysis.> In both –vacuolization >--blebs –burst >and create leasons though which neutrophilic/eos granulocytes can enter and cause lysis > >
What does Closantel treat?
Mature and immature stages of flukes. Effective against resistant strains of H. contortus
MOA of closantel?
Proton Ionophor: Uncouples oxidative phophorylation
inhibits glycolytic pathway → inhibition of ATP production
Protein Ionophor: Uncouples oxidative phophorylation → decreased ATP production
Which anti-trematodal is FDA approved for liver flukes?
Which anti-trematodal is highly protein bound (99%) with a half life of 17 days?
Which anti-trematodals are broad spectrum for immature and mature flukes?
Rafoxanide and closantel
Which anti-trematodal has metabolites that remain protein bound for 7 days?