Ivermectin, used as oral therapy for scabies, acts by which mechanism?

• A Inhibition of microtubule polymerization in the mite
• B Binding to glutamate-gated chloride channels causing paralysis ✓
• C Inhibition of chitin synthesis in the mite exoskeleton
• D Opening of voltage-gated sodium channels causing spastic paralysis

Explanation

Ivermectin binds selectively to glutamate-gated chloride channels found in invertebrate nerve and muscle cells, increasing chloride conductance. This causes hyperpolarization and paralysis of the mite, leading to its death. It does not cross the mammalian blood-brain barrier at therapeutic doses because mammals lack these specific glutamate-gated chloride channels. Permethrin acts on sodium channels, not ivermectin.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.