moxidectin

General

Pronunciation:
mox-i-dek-tin


Ther. Class.

anthelmintics

Indications

Treatment of onchocerciasis (River Blindness).

Action

Causes increased permeability, influx of chloride ions, hyperpolarization, and muscle paralysis; affects the microfilariae, but does not kill the adult worm.

Therapeutic Effect(s):

Reduction in skin microfilarial density.

Spectrum:

Onchocerca volvulus.

Pharmacokinetics

Absorption: Absorption ↑ with a high-fat meal.

Distribution: Widely distributed to tissues.

Metabolism and Excretion: Undergoes minimal hepatic metabolism; 2% excreted in feces as unchanged drug.

Half-life: 23 days.

TIME/ACTION PROFILE (plasma concentrations)

ROUTEONSETPEAKDURATION
POunknown4 hrunknown

Contraindication/Precautions

Contraindicated in:

  • None.

Use Cautiously in:

  • Severe renal impairment or end-stage renal disease
  • OB:   Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
  • Lactation:  Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
  • Pedi:  Children <12 yr (safety and effectiveness not established);
  • Geri:  Older adults may have ↑ sensitivity to adverse reactions.

Adverse Reactions/Side Effects

CV: hypotension, orthostatic hypotension, tachycardia, edema

Derm: pruritus, rash, urticaria

EENT: ↑ lacrimation, blurred vision, conjunctivitis, eyelid swelling, hyperemia, ocular itching, ocular pain, photophobia, watery eyes

F and E: hyponatremia

GI: abdominal pain, diarrhea, ↑ liver enzymes, hyperbilirubinemia

Hemat: eosinophilia, leukocytosis, lymphocytopenia, neutropenia, eosinopenia

MS: myalgia, arthralgia

Neuro: headache, dizziness, ENCEPHALOPATHY (if co-infected with  LOA LOA ), paresthesia

Resp: cough

Misc: chills, fever, lymphadenopathy

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

None reported.

Route/Dosage

PO (Adults and Children ≥12 yr): 8 mg as single dose.

Availability (generic available)

Tablets: 2 mg

Assessment

  • Assess for signs and symptoms of Mazzotti reaction of skin (pruritus, rash, urticaria), eyes (conjunctivitis, eye pain, eye pruritus, eyelid swelling, blurred vision, photophobia, changes in visual acuity, hyperemia, ocular discomfort, watery eyes), and systemic reactions (headache, fever, hypotension, tachycardia, edema, lymphadenopathy, arthralgia, myalgia, chills, paresthesia, asthenia). Usually occur and resolve during 1st wk after dose of moxidectin. Treat symptomatically with oral hydration, recumbency, antihistamines and/or analgesics. May use IV 0.9% NaCl, and/or parenteral corticosteroids to treat orthostatic hypotension.
  • Assess for symptomatic orthostatic hypotension (inability to stand without support after lying down for 5 minutes) following dose. Usually transient occurring Days 1 and 2 after dose. Manage by having patient lie down until symptoms resolve.
  • Assess for edema and worsening onchodermatitis (pruritus, unilateral leg or forearm swelling, rash, eye symptoms) after therapy. Treat symptomatically.

Lab Test Considerations:

Monitor for Mazzotti reactions after therapy. May cause eosinophilia, eosinopenia, lymphocytopenia, neutropenia, and ↑ALT, AST, gamma glutamyl transferase (GGT) and LDH. May also cause proteinuria.

Implementation

  • Conduct screening for loiasis before therapy in patients with exposure to Loa loa-endemic areas to decrease risk of encephalopathy.

  • PO Administer 4 tablet as a single dose without regard to food.

Patient/Family Teaching

  • Instruct patient to take moxidectin as directed.
  • Advise patients that if they feel dizzy or lightheaded after taking moxidectin tablets, they should lie down until the symptoms resolve.
  • Advise patient that flu like symptoms (malaise, myalgia, headache, tachycardia, hypotension, pruritus) may occur during 1st wk after treatment.
  • Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
  • Inform patient that moxidectin does not kill adult O. volvulus and follow up evaluation is usually required.

Evaluation/Desired Outcomes

Reduction in skin microfilarial density.