Systemic Antiparasitic Agents

  • Pregnancy Category C
Formulations and Dosage
  • Dose range: 150-400 μg/kg
  • Scabies: 200 μg/kg on day 1 and day 8-10
  • Lice: 400 μg/kg on day 1 and day 8
Mechanism of Action
  • Binds to glutamate- or GABA- gated chloride channels in muscle and nerves of invertebrates leading to hyperpolarization and death
  • Anthelmintic
Indications

FDA

  • Strongyloides stercolaris (intestinal strongyloidiasis), O. volvulus (onchocerciasis)

Off-label

  • Scabies, pediculosis, demodicosis, cutaneous larva migrans, pinworms, filariasis, other infestations/helminths (Mansonella, Trichuris, Ascaris, Gnathostomia)
  • Contraindicated in children <15kg, pregnancy and lactation
Side Effects
  • General: fever, lymphadenopathy
  • Skin: pruritus, Steven Johnson syndrome, Mazzotti reaction (fever, urticaria, tender lymphadenopathy and systemic symptoms; can be decreased by combination treatment with doxycycline)
  • Gastrointestinal: diarrhea, nausea
  • Cardiac: orthostatic hypotension, tachycardia
  • Neurologic: encephalopathy (rare, mainly in patients with Loiasis)
  • Mazzoti reaction: secondary to the treatment of nematodes
Other
  • Caution with CYP3A4 drugs
  • Dose adjustment required in liver dysfunction
  • Permethrin is more efficacious for scabies
  • Best for mass infestations (hospitals, care facilities)
  • Resistance reported (including scabies in endemic areas)
  • Norwegian (crusted) scabies: oral ivermectin combined with topical scabicides and keratolytic agents indicated

  • Pregnancy Category C
Formulations and Dosage
  • 400 mg BID x 28 days for neurocysticercosis, hydatid cyst
  • 400 mg x 1 dose for off-label indications
Mechanism of Action
  • Inhibits tubulin polymerization inhibiting motility and causing death
  • Also has potent anti-angiogenic effect (inhibits VEGF, endothelial cell migration)

Anthelminthic and antiprotozoal

Indications

FDA

  • Hydatid cyst, neurocysticercosis

Off-label

  • Giardiasis, tapeworms, hookworms, crusted scabies
Side Effects
  • Gastrointestinal: hepatotoxicity, diarrhea
  • Skin: rash, pruritis, urticaria
  • Hematologic: bone marrow suppression, aplastic anemia, agranulocytosis (higher risk with liver dysfunction)
  • Neurologic: headache, dizziness
Other
  • Should be taken with fatty meal to increase bioavailability
  • Should not be taken during pregnancy; pregnancy test should be done before treatment
  • CYP1A2 inducer
  • Should monitor complete blood count and liver function tests (at baseline and every 2 weeks while on therapy)
  • Resistance emerging

  • Pregnancy Category C
Formulations and Dosage
  • Weight based dosage BID x 2-7 days
Mechanism of Action
  • Exact unknown; though to inhibit helminth-specific fumarate reductase Anthelminthic

Anthelmintic and antiprotozoal

Indications

FDA

  • Cutaneous larva migrans, visceral larva migrans, strongyloidiasis

Off-label

  • Trichinosis, pinworms, whipworms, ascariasis
Side Effects
  • Gastrointestinal: anorexia, nausea, vomiting, hepatotoxicity
  • Neurologic: headache
  • Skin: Steven Johnson syndrome reports
Other
  • CYP1A2 inhibitor
  • Use with caution and adjust dose for impaired liver and renal function
  • Resistance emerging