Ivermectin

Ivermectin is used to treat a range of helminth and ectoparasite infections.

• Onchocerciasis: reduces microfilarial load and helps prevent blindness.
• Strongyloidiasis: eradicates intestinal larvae and prevents systemic dissemination.
• Lymphatic filariasis: eliminates adult worms and microfilariae to control disease spread.
• Scabies: kills Sarcoptes scabiei mites, relieving itching and skin lesions.
• Pediculosis: eliminates head lice infestations, reducing transmission.

• Ivermectin binds selectively to glutamate‑gated chloride channels in the nerve and muscle cells of invertebrates. This binding increases chloride ion influx, hyperpolarizing the cell membrane, leading to paralysis and death of the parasite while having minimal effect on mammalian cells due to the absence of these channels in humans.

Ivermectin may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Diarrhea: loose stools occurring shortly after dosing.
• Dizziness: transient light‑headedness.
• Abdominal pain: cramping or discomfort.
• Pruritus: itching at the site of parasite death.
• Headache: mild tension‑type headache.

Serious or Rare Side Effects

• Stevens‑Johnson syndrome: severe skin reaction requiring immediate medical attention.
• Hepatic injury: elevated liver enzymes or jaundice.
• Severe hypotension: sudden drop in blood pressure.
• Seizures: rare neurologic events.
• Anaphylaxis: acute allergic reaction with airway compromise.
• Visual disturbances: blurred vision or optic neuritis.

Before prescribing Ivermectin, clinicians should consider several safety measures.

• Assess for Loa loa infection: avoid in patients with high microfilaremia due to risk of severe reactions.
• Review liver function: adjust use in hepatic impairment.
• Monitor neurologic signs: watch for dizziness, seizures, or altered mental status.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Use caution in pregnancy: safety category unknown, weigh benefits against risks.
• Store at ambient temperature: keep in the original pack, protect from moisture.

Ivermectin can interact with other medicines, affecting safety or efficacy.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase ivermectin plasma levels.
• Warfarin: concurrent use may enhance anticoagulant effect and bleeding risk.
• Other neurotoxic antiparasitics (e.g., albendazole): may increase neurotoxicity.
• P‑glycoprotein inhibitors (e.g., verapamil): can raise systemic exposure.
• QT‑prolonging agents: combined use may raise arrhythmia risk.

Moderate Interactions (Monitor Closely)

• CYP3P4 inducers (e.g., rifampin): may reduce ivermectin effectiveness.
• Additional antiparasitics: monitor for additive side effects.
• Anticoagulants other than warfarin: observe coagulation parameters.
• Statins: watch for signs of myopathy.
• Antihistamines: may increase sedation.