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Pronunciation
(eye ver MEK tin)
U.S. Brand Names
Generic Available
No
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 nematode parasite Onchocerca volvulus. Ivermectin is only active against the immature form of Onchocerca volvulus, and the intestinal forms of Strongyloides stercoralis.
Use: Unlabeled/Investigational
Has been used for other parasitic infections including Ascaris lumbricoides, Bancroftian filariasis, Brugia malayi, scabies, Enterobius vermicularis, Mansonella ozzardi, Gnathostomia spingerum, Mansonella ozzardi, Mansonella streptocera, pediculosis pubis, Trichuris trichiura.
Pregnancy Risk Factor
C
Pregnancy Considerations
Teratogenic effects have been observed in animal studies. Safety has not been established in pregnant women. The manufacturer and the Centers for Disease Control and Prevention (CDC) do not recommend use in pregnant women.
Lactation
Enters breast milk/not recommended
Breast-Feeding Considerations
Safety and efficacy for use in children <15 kg have not been established in the U.S.; therefore, ivermectin use is not recommended during lactation.
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.
• Pediatrics: Safety and efficacy have not be established in children <15 kg.
Adverse Reactions
>10%: Miscellaneous: Mazzotti-type reaction (with onchocerciasis): Pruritus (28%), fever (23%), skin involvement (including edema/urticarial rash [23%]), 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%)
Ocular: Limbitis (4% to 6%), punctuate opacity (1% to 2%)
<1%, postmarketing, and/or case reports: Abdominal pain, anemia, anorexia, anterior uveitis, asthma exacerbation, back pain, bilirubin increased, chest discomfort, chorioretinitis, choroiditis, coma, confusion, conjunctival hemorrhage, conjunctivitis, constipation, dyspnea, encephalopathy (rare; associated with loiasis), eyelid edema, eye sensation abnormal, fatigue, fecal incontinence, headache, hypotension, INR increased, 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), weakness, vomiting
Metabolism/Transport Effects
Substrate of CYP3A4 (minor)
Drug Interactions
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
Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. 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
Absorption: Well absorbed
Distribution: Does not cross blood-brain barrier
Half-life elimination: ~18 hours
Metabolism: Hepatic (>97%)
Bioavailability: Increased with high-fat meal
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 the adult worms die
Weight-based dosage to provide ~150 mcg/kg:
15-25 kg: 3 mg
26-44 kg: 6 mg
45-64 kg: 9 mg
65-84 kg: 12 mg
?85 kg: 150 mcg/kg
Strongyloidiasis: 200 mcg/kg as a single dose; perform follow-up stool examinations; CDC recommendations: 200 mcg/kg/day for 2 days
Weight-based dosage to provide ~200 mcg/kg:
15-24 kg: 3 mg
25-35 kg: 6 mg
36-50 kg: 9 mg
51-65 kg: 12 mg
66-79 kg: 15 mg
?80 kg: 200 mcg/kg
Ascariasis due to Ascaris lumbricoides (unlabeled use): CDC recommendation: 150-200 mcg/kg as a single dose
Filariasis due to Mansonella ozzardi (unlabeled use): CDC recommendation: 200 mcg/kg as a single dose
Filariasis due to Mansonella streptocera (unlabeled use): CDC recommendation: 150 mcg/kg as a single dose
Gnathostomiasis due to Gnathostomia spingerum (unlabeled use): CDC recommendation: 200 mcg/kg/day for 2 days
Scabies due to Sarcoptes scabiei (unlabeled use): CDC recommendation: 200 mcg/kg as a single dose; repeat in 2 weeks
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.
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
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet [scored]:
Stromectol®: 3 mg
Pricing: U.S. (www.drugstore.com)
Tablets (Stromectol)
3 mg (20): $111.17
References
de Silva N, Guyatt H, and Bundy D, “Anthelmintics. A Comparative Review of Their Clinical Pharmacology,” Drugs, 1997, 53(5):769-88.
Centers for Disease Control and Prevention: “River Blindness Onchoceriasis.” Available at http://www.cdc.gov/ncidod/dpd/parasites/onchocerciasis/factsht_onchocerciasis.pdf; last accessed September 29, 2008.
Centers for Disease Control and Prevention, “Ascariasis (Ascaris lumbricoides, roundworm).” Available at http://www.dpd.cdc.gov/DPDx/HTML/PDF_Files/MedLetter/Ascariasis.pdf; last accessed September 29, 2008.
Centers for Disease Control and Prevention, “Filariasis.” Available at http://www.dpd.cdc.gov/dpdx/HTML/PDF_Files/MedLetter/Filariasis.pdf; last accessed September 29, 2008.
Centers for Disease Control and Prevention, “Gnathostomiasis (Gnathostoma spinigerum).” Available at http://www.dpd.cdc.gov/dpdx/HTML/PDF_Files/MedLetter/Gnathostomiasis.pdf; last accessed September 29, 2008.
Centers for Disease Control and Prevention, “Scabies (Sarcoptes scabiei).” Available at http://www.dpd.cdc.gov/dpdx/HTML/PDF_Files/MedLetter/Scabies.pdf; last accessed September 29, 2008.
Centers for Disease Control and Prevention, “Strongyloides (Strongyloides stercoralis).” Available at http://www.dpd.cdc.gov/dpdx/HTML/PDF_Files/MedLetter/Strongyloidiasis.pdf; last accessed September 29, 2008.
“Drugs for Parasitic Infections,” Med Lett Drugs Ther, 1993, 35(911):111-22.
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 2009
Content last modified May 2009
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