Drug Detail:Ivermectin (Ivermectin (oral) [ eye-ver-mek-tin ])
Drug Class: Anthelmintics
Usual Adult Dose for Onchocerciasis
0.15 mg/kg orally once every 12 months
Patients with heavy ocular infection may require retreatment every 6 months. Retreatment may be considered at intervals as short as 3 months.
Dosage guidelines based on body weight:
15 to 25 kg: 3 mg orally one time
26 to 44 kg: 6 mg orally one time
45 to 64 kg: 9 mg orally one time
65 to 84 kg: 12 mg orally one time
85 kg or more: 0.15 mg/kg orally one time
Usual Adult Dose for Strongyloidiasis
0.2 mg/kg orally once
In immunocompromised (including HIV) patients, the treatment of strongyloidiasis may be refractory requiring repeated treatment (i.e., every 2 weeks) and suppressive therapy (i.e., once a month), although well-controlled studies are not available. Cure may not be achievable in these patients.
Dosage guidelines based on body weight:
15 to 24 kg: 3 mg orally one time
25 to 35 kg: 6 mg orally one time
36 to 50 kg: 9 mg orally one time
51 to 65 kg: 12 mg orally one time
66 to 79 kg: 15 mg orally one time
80 kg or more: 0.2 mg/kg orally one time
Usual Adult Dose for Ascariasis
0.2 mg/kg orally once
Usual Adult Dose for Cutaneous Larva Migrans
0.2 mg/kg orally once
Usual Adult Dose for Filariasis
0.2 mg/kg orally once
Study (n=26,000)
Mass treatment in Papua, New Guinea:
Bancroftian filariasis: 0.4 mg/kg orally once yearly (with a single annual dose of diethylcarbamazine 6 mg/kg), for 4 to 6 years
Usual Adult Dose for Scabies
0.2 mg/kg orally once, and repeated in 2 weeks
Ivermectin therapy may be combined with a topical scabicide.
Usual Pediatric Dose for Filariasis
Study (n=26,000)
Mass treatment in Papua, New Guinea:
Bancroftian filariasis:
5 years or older: 0.4 mg/kg orally once yearly (with a single annual dose of diethylcarbamazine 6 mg/kg), for 4 to 6 years
Renal Dose Adjustments
Data not available
Liver Dose Adjustments
Data not available
Dose Adjustments
Retreatment is required because ivermectin has no activity against adult onchocerca volvulus parasites which tend to reside in subcutaneous nodules. Surgical excision of these nodules may be considered to eliminate the adult reproduction of microfilariae.
Patients with crusted scabies may require two or more doses of ivermectin spaced at one to two week intervals.
Precautions
Cutaneous, systemic and/or ophthalmological reactions have been reported with other microfilaricidal drugs. Allergic and inflammatory reactions (the Mazzotti reaction) may occur with ivermectin, probably due to the death of the microfilariae. Patients treated with ivermectin therapy for onchocerciasis may experience these reactions in addition to clinical adverse reactions possibly, probably, or definitely related to the therapy itself. The treatment of severe Mazzotti reactions has not been subjected to controlled clinical studies. Oral or intravenous rehydration, corticosteroids, antihistamines, acetaminophen and/or aspirin have been used for treatment.
After treatment with microfilaricidal medications, patients with hyperreactive onchodermatitis (sowda) may be more likely than others to experience severe adverse reactions, especially edema and aggravation of onchodermatitis.
Serious or fatal encephalopathy has been reported rarely in patients with onchocerciasis, and heavily infected with Loa loa, either spontaneously or after treatment with ivermectin. In these patients, pain (including neck and back pain), red eye, conjunctival hemorrhage, dyspnea, urinary and/or fecal incontinence, difficulty in standing/walking, mental status changes, confusion, lethargy, stupor, seizures, or coma have been reported. This syndrome has been seen very rarely following the use of ivermectin therapy. Pretreatment assessment for loiasis and careful posttreatment follow-up should be implemented in all patients considered for treatment with ivermectin for any reason and who had exposure to Loa loa endemic areas of West and Central Africa.
The patient should be advised of the need for repeated stool examinations to document clearance of infection with Strongyloides stercoralis.
The patient should be advised that treatment with ivermectin does not kill the adult Onchocerca parasites, and therefore repeated follow-up and retreatment is usually necessary.
In immunocompromised (including HIV-infected) patients being treated for intestinal strongyloidiasis, repeated courses of therapy may be necessary. Adequate and well-controlled clinical trials have not been conducted in such patients to determine the optimal dosing regimen. Several treatments, i.e., at 2-week intervals, may be required, and cure may not be attained. Control of extraintestinal strongyloidiasis in these patients is difficult, and suppressive therapy, i.e., once per month, may be useful.
Ivermectin is extensively metabolized in the liver and should be used cautiously in patients with hepatic disease. Dosage adjustments may be needed, although specific recommendations are not currently available. The manufacturer does not recommend that ivermectin treatment be excluded in patients with liver disease.
Clinical trials of ivermectin did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience has not identified differences in responses between elderly and younger patients. In general, treatment of elderly patients should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Safety and effectiveness in pediatric patients weighing less than 15 kg have not been determined.
Dialysis
Data not available
Other Comments
Each ivermectin dose should be taken on an empty stomach with a full (8 oz) glass of water.
A recent pharmacokinetics study reports that following a high-fat meal absorption was significantly higher (about 2.5 times) than in the fasted state.
Frequently asked questions
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