FDA - NADA 131-392
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FOI Summary;
NADA 131-392 (original); IVOMEC® (Ivermectin); July 26, 1988
--Editor's abstract
1. General Information
New Animal Drug Application Number: 131-392
Sponsor:
Merck Sharp and Dohme Research Laboratories
Division of MERCK &
CO., Inc. P.O. Box 2000
Rahway, New Jersey 07065
Generic Name of Drug: Ivermectin
Trade Name: IVOMEC® Liquid For Sheep
Marketing Status: Over The Counter
2. Indications for Use
For the control of the following parasites in sheep.
- Gastrointestinal nematodes:
- Haemonchus contortus (adults and fourth-stage larvae)
H. placei (adults)
Ostertagia circumcincta (adults and fourth-stage larvae)
Trichostrongylus axei (adults and fourth-stage larvae)
T. colubriformis (adults and fourth-stage larvae)
Cooperia curtitei (adults and fourth-stage larvae)
C. oncophora (adults)
Nematodirus spathiger (adults and fourth-stage larvae)
N. battus (adults and fourth-stage larvae)
Strongyloides papillosus (adults)
Oesophagostomum columbianum (adults and fourth-stage larvae)
Oes. venulosum (adults)
Trichuris ovis (adults)
Chabertia ovina (adults) - Lungworms:
- Dictyocaulus filaria (adults and fourth-stage larvae)
- Nasal bots:
- Oestrus ovis (first-, second- and third-instars)
3. Dosage:
a. A ready-to-use liquid 0.08% w/v micellar formulation of ivermectin.
b. Route of administration: oral (by drench).
c. Recommended Dosage: IVOMEC Sheep Drench is administered orally at a dose of
3.0 mL (2.4 mg ivermectin) per 26 lbs body weight or 200 mcg ivermectin per
kilogram of body weight.
4. Effectiveness
Ivermectin for the treatment of parasites affecting sheep was evaluated in 35 controlled efficacy trials. There were 748 sheep involved, of which 520 were given ivermectin and 228 served as controls.
Dose-Titration Trials
Dose-titration studies were carried out to determine the dose of ivermectin given once orally that would control gastrointestinal nematodes, lungworms, and nasal bots. Nineteen trials were conducted using ll9 control and 373 ivermectin-treated sheep. Dosages of 50 mcg/kg to 400 mcg/kg were employed. Local procedures were followed regarding animal husbandry during the trials as well as for allocating, dosing, collecting samples, enumerating and identifying parasites, and performing necropsies. The parasitisms were artificially induced in 13 of the trials, naturally acquired in two trials, and induced infections were superimposed in four trials. Based on the data collected, a minimum effective dose of 200 mcg ivermectin/kg bodyweight was determined.
Trial 4828 was conducted in the United States to establish the optimum effective level of ivermectin against nematodes. Sheep were given infective larvae on days 27 and 7 before treatment. Prior to treatment, 25 sheep were randomly allocated to four groups. Ten sheep were used as controls and the other groups had five sheep each. Control sheep were given propylene glycol vehicle, and ivermectin was given once orally to the sheep in the other groups at 50 mcg/kg, 100 mcg/kg, or 200 mcg/kg. Necropsies were performed seven days after treatment, and the reductions listed below were recorded. No adverse reactions occurred. Data from 15 additional sheep given another drug are irrelevant to this summary and have been deleted.
........................ % Reduction (mcg/kg) Nematodes......50.......100.......200
[See pdf for complete file, which includes all tables and data]