Dirofilariasis Medication

Updated: Oct 05, 2015
  • Author: Alena Klochko, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Medication

Medication Summary

Biochemical pathways in parasites are different from those in their human host; thus, the toxicity of anthelmintics is directed at the parasite, egg, or larvae. The mechanism of action varies within the drug class. Antiparasitic actions may include the following:

  • Inhibition of microtubules, causing irreversible blockage of glucose uptake
  • Tubulin polymerization inhibition
  • Depolarizing neuromuscular blockade
  • Cholinesterase inhibition
  • Increased cell membrane permeability, resulting in intracellular calcium loss
  • Vacuolization of the schistosome tegument
  • Increased cell membrane permeability to chloride ions via chloride channels alteration
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Anthelmintics

Class Summary

Biochemical pathways in parasites are different from those in the human host; thus, the toxicity of anthelmintics is directed at the parasite, egg, or larvae. The mechanism of action varies within the drug class. Ivermectin, for example, acts as a potent agonist at gamma-aminobutyric acid (GABA) receptors and potentiates the inhibitory signals sent to motor neurons, paralyzing the nematode.

Ivermectin (Stromectol)

Ivermectin is a macrocyclic lactone derivative of avermectin (22,23-dihydroavermectin). It binds selectively with glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, causing cell death. The drug, which is metabolized in the liver, has a 16-hour half-life.

Ivermectin exerts its antiparasitic action by acting as a potent agonist at GABA receptors and potentiating the inhibitory signals sent to motor neurons, paralyzing the parasite. Because GABA is confined to the central nervous system (CNS) in humans and ivermectin does not cross the blood-brain barrier, the drug has no paralytic action in humans.

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