Term
| List the benzimidazoles discussed in class. |
|
Definition
Thiabendazole
Albendazole
Fenbendazole
Febantel
Oxfendazole
Oxibendazole |
|
|
Term
| What class of anthelmintics works by selectively binding beta-tubulin of worms, damaging the intestine of the worm and causing it to starve to death? |
|
Definition
Benzimidazoles
Benzimidazoles also inhibit egg production and inhibit reproduction by inhibition of the worm's cilia/flagella. |
|
|
Term
| Which benzimidazoles are the most (about 50%) absorbed? |
|
Definition
Thiabendazole
Albendazole
Oxfendazole |
|
|
Term
| T/F: benzimidazoles are generally not very well absorbed. |
|
Definition
| True. Benzimidazoles have low water solubility and are therefore not readily absorbed. The exceptions are thiabendazole, albendazole, and oxfendazole, which are about 50% absorbed. |
|
|
Term
| What should be included in the ruminant diet to increase the bioavailability, efficacy, and time in the rumen when administering benzimidazoles? |
|
Definition
| Fiber should be fed, rather than concentrates. |
|
|
Term
| T/F: benzimidazoles are better absorbed from the GI tract of monogastrics when administered with a full meal, as bile salts help with absorption. |
|
Definition
| True. This is especially important for worms outside the GI tract. |
|
|
Term
| What is the spectrum of most benzimidazoles? |
|
Definition
| Larvae and adults of most nematodes. Broad spectrum. |
|
|
Term
| T/F: benzimidazoles have been used with much success against filariae. |
|
Definition
| False. Benzimidazoles are ineffective against filariae. |
|
|
Term
| How long are residues of benzimidazoles in the liver following dosing? |
|
Definition
|
|
Term
| What must be done to the dose of benzimidazoles for them to be effective against hypobiotic larvae? |
|
Definition
| 2x the dose must be administered. |
|
|
Term
| Which benzimidazoles are teratogenic if administered during the first trimester? |
|
Definition
| Thiabendazole, Albendazole, Oxfendazole |
|
|
Term
| T/F: All benzimidazoles have a low incidence of hepatotoxicity and testicular toxicity in dogs and cats. |
|
Definition
|
|
Term
| When given at 2x the normal dose, _________will kill adult flukes when they are in the __________ (anatomic location). |
|
Definition
|
|
Term
| Albendazole is indicated for use in what species? |
|
Definition
|
|
Term
Which of the following drugs is indicated for treatment of Moniezia, cysticercus of Taenia, and hydatid cysts of Echinococcus?
a. Fenbendazole
b. Albendazole
c. Oxfendazole
d. A and B
e. B and C |
|
Definition
| B and C. Albendazole and Oxfendazole can be used vs. moniezia, cysticercus of Taenia, and hydatid cysts of Echinococcus. |
|
|
Term
| What is the only benzimidazole that is approved for use in lactating dairy cattle? |
|
Definition
|
|
Term
| T/F: fenbendazole, oxibendazole, and oxfendazole can be used against all stages of strongyles in horses. |
|
Definition
False: these benzimidazoles are only good vs. mature strongyles in horses.
Note: These benzimidazoles can also be used against Oxyuris, Trichostrongylus, and Parascaris in horses, but have limited activity vs. cyathostomes, immature strongyles, and dictyocaulus. |
|
|
Term
| T/F: leukopenia is a side effect that is seen with all benzimidazoles. |
|
Definition
|
|
Term
| Which benzimidazole can be used in Ruminants, Horses, Cattle, and Small Animals? |
|
Definition
|
|
Term
| Is there a withdrawal period for swine being treated with fenbendazole? |
|
Definition
|
|
Term
| Which benzimidazole can be used vs. Taenia and Echinococcus in dogs and cats? |
|
Definition
|
|
Term
| Macrolide antibiotics are originally from what bacteria? |
|
Definition
|
|
Term
| List the Avermectins discussed in class: |
|
Definition
Ivermectin
Eprinomectin
Doramectin
Selamectin |
|
|
Term
| List the Milbemycins discussed in class: |
|
Definition
|
|
Term
| T/F: the avermectins are more lipid soluble and longer lasting/potent than milbemycins. |
|
Definition
| False: Milbemycins (milbemycin, moxidectin) are more lipid soluble, longer lasting, and potent than avermectins. |
|
|
Term
| List the mechanisms of action for the Avermectins/Macrocyclic Lactones: |
|
Definition
1. Allosteric modulator of ligand-gated ion channels, particularly invertebrate glutamate-gated *chloride* channels (GluCls)
2. Opens glutamate-gated (non-mammal) and GABA-gated (invertebrate/mammal) *chloride* channels to hyperpolarize the muscle of nematodes, insects, and crustaceans, causing *paralysis*
3. Inhibits movement, pharyngeal pumping, and egg laying in nematodes due to increased inhibitory ion channels.
4. Inhibits muscle contraction in insects because GluCl are present on body muscle. |
|
|
Term
| T/F: avermectins are lipophilic and are therefore rapidly absorbed and have slow kinetics due to storage in fat deposits. |
|
Definition
|
|
Term
| Is the half-life of oral or subcutaneous avermectins longer? |
|
Definition
Subcutaneous
The oral T1/2 is 12 hours, while the SC is 2 days. |
|
|
Term
| Where are the highest concentrations of avermectins in the body? The lowest concentrations? |
|
Definition
Highest: liver, bile, fat
Lowest: brain |
|
|
Term
| What host channel pumps avermectins out of the host brain? |
|
Definition
|
|
Term
| Where are avermectins metabolized and excreted? |
|
Definition
Metabolized in liver and fat to polar and nonpolar fatty acid esters.
Excreted in feces via bile. |
|
|
Term
| What is the spectrum for the avermectins? |
|
Definition
Adult and larval stages of nematodes
Filaria (NOT adults)
Insects, lice, mites |
|
|
Term
| T/F: avermectins are effective against flukes, tapeworms, and fleas |
|
Definition
|
|
Term
| Which avermectin has no preslaughter withdrawal time and no milk discard time? |
|
Definition
Eprinomectin
Note: moxidectin has no preslaughter or milk withdrawal if administered *topically* |
|
|
Term
| T/F: ivermectin is an effective treatment vs. encysted Trichinella in swine. |
|
Definition
|
|
Term
| What canine species should not be given ivermectin? |
|
Definition
| Collies--mutation of P-glycoprotein prevents removal of ivermectin from their brain. This leads to an ivermectin accumulation and CNS signs. |
|
|
Term
| T/F: avermectins are safe for pregnant animals. |
|
Definition
|
|
Term
| Against what parasites is ivermectin effective in horses? |
|
Definition
Bots
Stomach worms
Strongyles
Pinworms
Ascarids |
|
|
Term
| Which avermectin is a topical analog of ivermectin? |
|
Definition
|
|
Term
| Which avermectin(s) is/are indicated for use in small animals for heartworms, fleas, sarcoptic mites, ear mites, and ticks? |
|
Definition
Selamectin
Note: Moxidectin and Milbemycin are also indicated for use vs. heartworms in small animals |
|
|
Term
| Which avermectin is considered a good choice for administration to a Collie? |
|
Definition
|
|
Term
| Which avermectin/macrocyclic lactone is considered an aglycone, where only 10% of the dose is absorbed? |
|
Definition
|
|
Term
| Which avermectin/macrocyclic lactone is indicated for the treatment of demodicosis? |
|
Definition
|
|
Term
| What is the mechanism of action for Levamisole? |
|
Definition
| Levamisole causes spastic paralysis due to the drug selectively binding to the nematode's UNC-38 nicotinic receptors. Levamisole is a cholinergic agonist. |
|
|
Term
| T/F: levamisole has excellent GI absorption and evenly distributes across the BBB. |
|
Definition
|
|
Term
| What are the species and spectrum for which levamisole is effective? |
|
Definition
Ruminants and Swine
Effective against GI worms and lungworms in cattle.
Effective against ascarids, threadworms, whipworms, nodular worms, lungworms, and kidney worms in swine. |
|
|
Term
| T/F: levamisole is too toxic for horses, dogs, and cats due to the fact that their muscarinic receptors are too sensitive. |
|
Definition
True
Horses > pigs > sheep > cattle |
|
|
Term
| What are some consequences of levamisole toxicity? |
|
Definition
| Cholinergic muscarinic stimulation: salivation, bradycardia, colic, urination, uncoordination, asphyxia due to respiratory paralysis, cardiac arrhythmias |
|
|
Term
| Which anthelmintic(s) have the same mechanism of action as levamisole? |
|
Definition
|
|
Term
| T/F: pyrantel and morantel are more restricted to the GI tract, thereby reducing the toxic effects and making them available to horses, dogs, and cats. |
|
Definition
|
|
Term
| Pyrantel __________ is more water soluble, while pyrantel __________ is less water soluble. |
|
Definition
|
|
Term
| Against what parasites is Pyrantel effective in horses? |
|
Definition
Strongyles, ascarids, pinworms, tapeworms
Anoplocephala perfoliata--*double the dose* |
|
|
Term
| T/F: pyrantel is an effective treatment vs. bots in horses. |
|
Definition
|
|
Term
| T/F: pyrantel is an effective treatment vs. ascarids and hookworms in dogs/cats. |
|
Definition
|
|
Term
| What is pyrantel ineffective in treating in dogs/cats? |
|
Definition
|
|
Term
| Cross-resistance can occur between levamisole and ___________. |
|
Definition
Pyrantel
Maybe morantel too? |
|
|
Term
| Morantel is indicated for use in what species? |
|
Definition
|
|
Term
| What is the mechanism of action of Monepantel? |
|
Definition
| Monepantel causes spastic paralysis due to selective binding of nematode ACR-23 receptors. |
|
|
Term
| Monepantel is indicated for use in what species? |
|
Definition
|
|
Term
| T/F: cross-resistance occurs between levamisol/pyrantel and monepantel. |
|
Definition
|
|
Term
| What is the mechanism of action of dichlorvos? |
|
Definition
| Dichlorvos inactivates cholinesterase by covalently binding it. This leads to an increase in acetylcholine. |
|
|
Term
| Dichlorvos is indicated for use in what species? |
|
Definition
| Swine--mature/immature ascarids, whipworms, nodular worms, stomach worms |
|
|
Term
| Toxicity to Dichlorvos involves what clinical signs? |
|
Definition
| Salivation, bradycardia, peristalsis, urination, defecation, paralysis (acute death due to respiratory paralysis) |
|
|
Term
| How can toxicity to Dichlorvos be reversed? |
|
Definition
|
|
Term
| What is the name of the only organophosphate nematocide available? |
|
Definition
|
|
Term
| What is the mechanism of action of emodepside? |
|
Definition
Emodepside is a cyclic despipeptide and acts by activation of calcium dependent K channels, activation of latrophillin receptors, and release of PF1 and PF2 inhibitory peptides.
Emodepside inhibits muscle activity. |
|
|
Term
| How is emodepside absorbed? How is it excreted? |
|
Definition
Emodepside is absorbed through the skin and deposited in fat as a reservoir.
It is excreted in the bile/feces. |
|
|
Term
| What is the spectrum and for what species is emodepside indicated? |
|
Definition
Ascarids and hookworms (mature, immature, larva)
Indicated for use in dogs and cats |
|
|
Term
| T/F: emodepside is safe in pregnant and lactating animals. |
|
Definition
|
|
Term
| What are some side effects of emodepside? |
|
Definition
| Salivation, vomiting, tremors |
|
|
Term
| What is the mechanism of action of piperazine? |
|
Definition
| Piperazine is a GABA agonist that induces hyperpolarization of excitable cells of the nematode muscle. This causes a flaccid paralysis. |
|
|
Term
| For what species is piperazine indicated? |
|
Definition
Horses, Swine, Dogs/Cats
Limited use in cattle
Used vs. nodular worms, ascarids, pinworms |
|
|
Term
| What anthelmintic drug is known to cause CNS ataxia in kittens at high doses? |
|
Definition
|
|
Term
| What is the mechanism of action for melarsamine? |
|
Definition
| Melarsamine is an arsenic compound that denatures proteins by binding to -SH groups of cysteine residues. |
|
|
Term
| What is melarsamine used to treat? |
|
Definition
|
|
Term
| What are the side effects of melarsamine toxicity? |
|
Definition
Local irritation, hind limb weakness, paralysis, distress, salivation, tachycardia, tachypnea, pawing, abdominal pain, recumbency, circulatory collapse
Liver toxicity
Nephrotoxicity
Thromboembolic pneumonia due to dead worm accumulation and Wolbachia |
|
|
Term
| Nephrotoxicity due to Melarsamine toxicity can be treated with ______________. |
|
Definition
|
|
Term
| Thromboembolic pneumonia due to melarsamine toxicity can be treated with what? |
|
Definition
Anti-inflammatories
Antibiotics
Rest for 2 weeks
GC |
|
|
Term
| What other organism is often paired with heartworms and can cause problems when melarsamine treatment is initiated? |
|
Definition
Wolbachia
Treat with doxycycline |
|
|
Term
| What is the mechanism of action of praziquantel? |
|
Definition
| Praziquantel functions by binding to the B-subunit and opening calcium channels, resulting in the paralysis and digestion of tapeworms, irreversible focal vacuolization, and disintegration of integument. |
|
|
Term
| T/F: praziquantel is rapidly absorbed and evenly distributed throughout the body, including the CNS. |
|
Definition
|
|
Term
| T/F: praziquantel is effective against all Taenia species and life stages, including hydatid cysts. |
|
Definition
| False: Praziquantel is ineffective against hydatid cysts and ova. |
|
|
Term
| What anthelmintic can be used vs. paragonimus lungworms in dogs/cats? |
|
Definition
|
|
Term
| T/F: Praziquantel is very teratogenic and embryotoxic and therefore should not be used in pregnant animals. |
|
Definition
|
|
Term
| What are some side effects of praziquantel administration? |
|
Definition
| Anorexia, vomiting, salivation, diarrhea, ataxia, tremors, lethargy |
|
|
Term
| Which anthelmintic is an analog of praziquantel? |
|
Definition
|
|
Term
| Where is praziquantel metabolized? Where is it excreted? |
|
Definition
| Praziquantel is metabolized in the liver and excreted in the urine. |
|
|
Term
| T/F: like praziquantel, epsiprantel is readily absorbed from the GI tract. |
|
Definition
| False: poor GI absorption; <0.1% is recovered in the urine. |
|
|
Term
| What is the mechanism of action of dichlorophene? |
|
Definition
| Dichlorophene disrupts the pH in the mitochondria of tapeworms to inhibit ATP synthesis by the uncoupling of oxidative phosphorylation. |
|
|
Term
| Against which species of tapeworms is dichlorophene effective? |
|
Definition
|
|
Term
| What is the mechanism of action of clorsulon? |
|
Definition
| Clorsulon decreases enzymes in the glycolytic pathway. |
|
|
Term
| T/F: clorsulon is rapidly absorbed from the GI tract and excreted as the parent drug in the urine and feces. |
|
Definition
|
|
Term
| Against what parasite is clorsulon effective? |
|
Definition
| Mature and *immature* Fasciola hepatica |
|
|
