BIMECTIN

Indications

• Onchocerciasis (river blindness)
• Lymphatic filariasis
• Strongyloidiasis
• Scabies
• Head lice
• Cutaneous larva migrans

Dosage

Children: Refer to the BNF for Children for guidance on pediatric dosing.

Adults: Refer to specific clinical guidelines or the BNF for exact dosing.

Mechanism of action

Ivermectin binds selectively to glutamate-gated chloride channels and other ligand-gated ion channels in the nerve and muscle cells of parasites. This binding increases the permeability of the cell membranes to chloride ions, leading to hyperpolarization, paralysis, and ultimately death of the parasites.

Pharmacodynamics

Ivermectin has a broad spectrum of activity against various nematodes and ectoparasites. It shows efficacy against adult worms and their larvae, as well as certain arthropods. The drug's effect is dependent on the concentration and exposure time; higher concentrations and prolonged exposure enhance its antiparasitic effects. It is generally well tolerated, with a low incidence of adverse effects in humans.

Pharmacokinetics

Ivermectin is well absorbed after oral administration, with peak plasma concentrations typically occurring within 4 to 5 hours. It has a large volume of distribution, with a significant portion of the drug binding to tissues, especially fat. The drug undergoes hepatic metabolism, primarily by cytochrome P450 enzymes, and is excreted mainly in the feces. The elimination half-life varies but is approximately 12 to 36 hours, depending on individual factors.

Contra-indications

• Hypersensitivity to ivermectin or any excipients
• Meningitis caused by Onchocerca volvulus
• Children weighing less than 15 kg

Adverse effects

• Headache
• Dizziness
• Pruritus
• Rash
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Fatigue
• Lymphadenopathy

Interactions

• CYP3A4 inducers may decrease ivermectin levels
• CYP3A4 inhibitors may increase ivermectin levels
• Concomitant use with other anthelmintics may have additive effects

Precautions

• Use with caution in patients with hepatic impairment
• Monitor for neurological adverse events in patients with onchocerciasis
• Consider potential for drug interactions with other medications

Pregnancy

Ivermectin should only be used in pregnancy if the potential benefit justifies the potential risk to the fetus, as data on its safety in pregnancy are limited.

Breast-feeding

Ivermectin is excreted in breast milk; caution is advised when administering to breastfeeding mothers.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Oral tablets
• Topical formulations