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Pronunciation
(eye ver MEK tin)
Generic Available (U.S.)
No
U.S. Brand Names
Pharmacologic Category
Use: Labeled Indications
Treatment of the following infections: Strongyloidiasis of the intestinal tract due to the nematode parasite Strongyloides stercoralis. Onchocerciasis due to the immature form of the nematode parasite Onchocerca volvulus
Use: Unlabeled/Investigational
Treatment of other parasitic infections, including Ancylostoma braziliense, Ascaris lumbricoides, Sarcoptes scabiei, Gnathostoma spinigerum, Mansonella ozzardi, Mansonella streptocerca, Pediculus humanus capitis, Pediculus humanus corporis, Phthirus pubis, Trichuris trichiura, Wucheria bancrofti
Pregnancy Risk Factor
C
Pregnancy Considerations
Teratogenic effects have been observed in animal reproduction studies; therefore, the manufacturer classifies ivermectin as pregnancy category C. Ivermectin is not recommended for use in pregnancy. Although studies during pregnancy are limited, several mass treatment programs have not identified an increased risk of adverse fetal, neonatal, or maternal outcomes following ivermectin use in the first and second trimesters.
Lactation
Enters breast milk/not recommended
Breast-Feeding Considerations
Ivermectin is measurable in low concentrations in breast milk and is less than maternal plasma concentrations. Peak concentrations of ivermectin in breast milk may occur 4-12 hours after the oral dose. In one study, the calculated infant daily dose was 2.75 mcg/kg in a 1-month-old infant and would not be expected to cause adverse effects in the infant. The manufacturer and the CDC do not have safety data in children <15 kg and the CDC does not recommend the use of ivermectin in lactating women.
Contraindications
Hypersensitivity to ivermectin or any component of the formulation
Warnings/Precautions
Concerns related to adverse effects:
• Cutaneous/systemic reactions: Data have shown that antihelmintic drugs like ivermectin may cause cutaneous and/or systemic reactions (Mazzoti reaction) of varying severity including ophthalmological reactions in patients with onchocerciasis. These reactions are probably due to allergic and inflammatory responses to the death of microfilariae. Patients with hyper-reactive onchodermatitis may be more likely than others to experience severe adverse reactions, especially edema and aggravation of the onchodermatitis.
Disease-related concerns:
• Loiasis: Pretreatment assessment for Loa loa infection is recommended in any patient with significant exposure to endemic areas (West and Central Africa); serious and/or fatal encephalopathy has been reported (rarely) during treatment in patients with loiasis.
Special populations:
• Immunocompromised patients: Repeated treatment may be required in immunocompromised patients (eg, HIV); control of extraintestinal strongyloidiasis may necessitate suppressive (once monthly) therapy.
Other warnings/precautions:
• Appropriate use: Onchocerca volvulus: Ivermectin has no activity against adult O. volvulus parasites.
Adverse Reactions
>10%: Miscellaneous: Mazzotti-type reaction (with onchocerciasis): Pruritus (28%), fever (23%), skin involvement (23%; including edema/urticarial rash), lymph node tenderness (1% to 14%), lymph node enlargement (3% to 13%), arthralgia/synovitis (9%)
1% to 10%:
Cardiovascular: Tachycardia (4%), peripheral edema (3%), facial edema (1%), orthostatic hypotension (1%)
Central nervous system: Dizziness (3%)
Dermatologic: Pruritus (3%)
Gastrointestinal: Diarrhea (2%), nausea (2%)
Hematologic: Eosinophilia (3%), leukocytes decreased (3%), hemoglobin increased (1%)
Hepatic: ALT increased (2%), AST increased (2%)
<1%, postmarketing, and/or case reports: Abdominal distention, abdominal pain, anemia, anorexia, anterior uveitis, asthma exacerbation, back pain, bilirubin increased, chest discomfort, chorioretinitis, choroiditis, coma, confusion, conjunctival hemorrhage (associated with onchocerciasis), conjunctivitis, constipation, dyspnea, encephalopathy (rare; associated with loiasis), eyelid edema, eye sensation abnormal, fatigue, fecal incontinence, headache, hepatitis, hypotension, INR increased (with concomitant warfarin), keratitis, lethargy, leukopenia, mental status changes, myalgia, neck pain, rash, red eye, seizure, somnolence, standing/walking difficulty, Stevens-Johnson syndrome, stupor, toxic epidermal necrolysis, tremor, urinary incontinence, urticaria, vertigo, vision loss (transient), vomiting, weakness
Metabolism/Transport Effects
Substrate of CYP3A4 (minor), P-glycoprotein
Drug Interactions
BCG: Antibiotics may diminish the therapeutic effect of BCG. Risk X: Avoid combination
Conivaptan: May increase the serum concentration of CYP3A4 Substrates. Management: Upon completion/discontinuation of conivaptan, allow at least 7 days before initiating therapy with drugs that are CYP3A4 substrates. Risk D: Consider therapy modification
P-Glycoprotein Inducers: May decrease the serum concentration of P-Glycoprotein Substrates. P-glycoprotein inducers may also further limit the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Risk C: Monitor therapy
P-Glycoprotein Inhibitors: May increase the serum concentration of P-Glycoprotein Substrates. P-glycoprotein inhibitors may also enhance the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Risk C: Monitor therapy
Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates. Risk C: Monitor therapy
Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 24 hours after cessation of antibacterial agents. Risk D: Consider therapy modification
Vitamin K Antagonists (eg, warfarin): Ivermectin may enhance the anticoagulant effect of Vitamin K Antagonists. Risk C: Monitor therapy
Ethanol/Nutrition/Herb Interactions
Food: Bioavailability is increased 2.5-fold when administered following a high-fat meal.
Storage
Store at <30°C (86°F).
Mechanism of Action
Ivermectin is a semisynthetic antihelminthic agent; it binds selectively and with strong affinity to glutamate-gated chloride ion channels which occur in invertebrate nerve and muscle cells. This leads to increased permeability of cell membranes to chloride ions then hyperpolarization of the nerve or muscle cell, and death of the parasite.
Pharmacodynamics/Kinetics
Onset of action:
Peak effect in treatment of onchocerciasis: 3-6 months
Peak effect in treatment of strongyloides: 3 months
Absorption: Well absorbed
Distribution: Vd: 3-3.5 L/kg (healthy males); does not cross blood-brain barrier
Protein binding: ~93%
Metabolism: Hepatic via CYP3A4 (major), CYP2D6 (minor), and CYP2E1 (minor)
Bioavailability: Increased with high-fat meal
Half-life elimination: ~18 hours
Time to peak, serum: ~4 hours
Excretion: Feces; urine (<1%)
Dosage
Oral: Children ≥15 kg and Adults:
Onchocerciasis: 150 mcg/kg as a single dose; retreatment may be required every 3-12 months until asymptomatic
Strongyloidiasis: Manufacturer recommendations: 200 mcg/kg as a single dose; perform follow-up stool examinations. Alternative dosing: 200 mcg/kg/day for 2 days
Ascariasis due to Ascaris lumbricoides (unlabeled use): 150-200 mcg/kg as a single dose
Cutaneous larva migrans (CLM) due to Ancylostoma braziliense (unlabeled use): 200 mcg/kg daily for 1-2 days
Filariasis due to Mansonella ozzardi (unlabeled use): 200 mcg/kg as a single dose
Filariasis due to Mansonella streptocerca (unlabeled use): 150 mcg/kg as a single dose
Filariasis due to Wucheria bancrofti (unlabeled use): 200 mcg/kg as a single dose given in combination with albendazole
Gnathostomiasis due to Gnathostoma spinigerum (unlabeled use): 200 mcg/kg/day for 2 days
Lice due to Pediculus humanus capitis, Pediculus humanus corporis, Phthirus pubis (unlabeled use): 200 mcg/kg/dose; generally requires more than 1 dose; number of doses and dosage intervals have not been established; 200 mcg/kg/dose for 3 doses every 7 days (Foucault, 2006) and 200 mcg/kg/dose repeated once after 10 days (Jones, 2003) have been shown to be effective; alternatively 400 mcg/kg/dose on days 1 and 8 has been utilized in Pediculus humanus capitis (Chosidow, 2010)
Scabies due to Sarcoptes scabiei (unlabeled use): 200 mcg/kg as a single dose; repeat in 2 weeks (drug of choice for immunocompromised patients with crusted scabies)
Trichuriasis due to Trichuris trichiura (unlabeled use): 200 mcg/kg/day for 3 days
Administration: Oral
Administer on an empty stomach with water.
Monitoring Parameters
Skin and eye microfilarial counts, periodic ophthalmologic exams; follow up stool examinations
Dietary Considerations
Take on an empty stomach with water.
Patient Education
You may have edema (peripheral or facial), dizziness, gastrointestinal upset (nausea or diarrhea), skin rash, or ophthalmic reaction.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause dizziness, drowsiness, or insomnia
Mental Health: Effects on Psychiatric Treatment
May cause leukopenia; use caution with clozapine and carbamazepine
Nursing: Physical Assessment/Monitoring
Pretreatment assessment for infection recommended for patients with exposure to endemic areas.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, oral:
Stromectol®: 3 mg
Pricing: U.S. (www.drugstore.com)
Tablets (Stromectol)
3 mg (20): $111.17
References
“American Academy of Pediatrics Committee on Drugs. The Transfer of Drugs and Other Chemicals Into Human Milk,” Pediatrics, 2001, 108(3):776-89.
Chosidow O, Giraudeau B, Cottrell J, et al, “Oral Ivermectin Versus Malathion Lotion for Difficult-to-Treat Head Lice,” N Engl J Med, 2010, 362(10):896-905.
de Silva N, Guyatt H, and Bundy D, “Anthelmintics. A Comparative Review of Their Clinical Pharmacology,” Drugs, 1997, 53(5):769-88.
“Drugs for Parasitic Infections,” Med Lett Drugs Ther, 2007, 5(Suppl):e1-15.
Foucault C, Ranque S, Badiaga S, et al, “Oral Ivermectin in the Treatment of Body Lice,” J Infect Dis, 2006, 193(3):474-6.
Frankowski BL and Bocchini JA Jr, “Head Lice,” Pediatrics, 2010, 126(2):392-403.
González CA, Sahagún Prieto AM, Diez Liébana MJ, et al, “The Pharmacokinetics and Interactions of Ivermectin in Humans--a Mini-Review,” AAPS J, 2008, 10(1):42-6.
Jones KN and English JC 3rd, “Review of Common Therapeutic Options in the United States for the Treatment of Pediculosis Capitis,” Clin Infect Dis, 2003, 36(11):1355-61.
Ottesen EA and Campbell WC, “Ivermectin in Human Medicine,” J Antimicrob Chemother, 1994, 34(2):195-203.
International Brand Names
Lexi-Comp.com
Last full review/revision May 2011
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