ANTIPARASITICS
Copyright, Purdue Research Foundation, 1996
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| Antiparasitics Intro. |
Overview
Antiparasitics, drugs which kill or inhibit the growth
of parasitic organisms, may be subdivided into the following therapeutic
categories:
- antinematodal
- anticestodal and antitrematodal
- antiprotozoal
- insecticide
Ideal Parasite Control
- Ideal parasite control -- good husbandry practices
- Vaccination -- second best
- Drugs Important
- Still necessary
- Of major importance
Characteristics of the ideal antiparasitic
- Effective at removing parasites -- They have a broad
spectrum of action. They are active against all developmental
stages of the parasite as well as against both tissue and
luminal forms.
- Safe to use -- They have a large Therapeutic index,
do not discolor body fluids or those who administer them. There
are no tissue residues and/or a short withdrawal
time. They do not interact with other drugs or environmental toxins.
They are not toxic to young or old animals.
- Convenient to use They are effective with one dose
treatment to minimize the cost and stress of handling the animals.
They have convenient dose forms that are easy to administer.
In some cases, this means an oral dose form. In others, e.g.,
where individual treatment of large numbers of cattle is required,
injectable forms are superior to oral forms. Because fasting is
both a nuisance and requires sometimes difficult pre-treatment
work, no-fasting is required. No-purgation is ideal
because it decreases the number of drugs, number of handlings,
and the resultant mess. Short withdrawal times allow more
rapid marketing and lessened need to keep treated animals specifically
identified.
- Low cost -- The drug itself as formulated must be inexpensive.
Moreover, particularly in mass therapy situations, it must be
inexpensive to administer. This includes labor cost and stress
(which is a cost) to the animal(s) being treated.
Routes of administration
- Many routes; depends on --
- Animals --
- Drug
- Pharmacokinetics
- Stability
- Oral -- most common
- Capsules, tablets, and boluses
can be given by hand or with a balling gun.
- Small amounts of a liquid
can be given with a dose syringe
- Irritating solution and large amounts of liquid
require installation of a stomach tube
- tube or paste gun
- Long term therapy and/or treatment of large numbers
- feed additives as powders or drug
impregnated resin beads are used. The beads may be less likely
to provide long term contamination of feed handling and mixing
equipment.
- mineral or salt supplements, blocks, or mixes
- drinking water
- Parenteralgenerally discouraged
- Risks
- syringes and needles
- introduction of infectious agents
- animals must be handled
- Advantageous
- animals going through chutes anyway
- deliver "Known" dose easily IM or SC
- Rarely: IV or intratracheally
- Topical many advantages
- Easy to spray large numbers of animals
- Dips
- Pour-ons and spot-ons are convenient and easy
- CONCERN: highly concentrated dose forms hazardous
ANTINEMATODAL DRUGS - TOXICITY - MOA
REFERENCES
- Barragry, TB, Clinical Pharmacology of Endoparasiticides, Chapter 4, pp 80-118, in Veterinary Drug Therapy, Lea & Febiger, Philadelphia, 1994
- Ching Chang Wang. Basic Principles of Antiparasitic Chemotherapy,
Ch. 55 in Basic and Clinical Pharmacology, 2nd ed., Ed by B.G
Katzung. Lange Medical Publications, Los Altos, CA, 1984. pp.
611-621.
- Mansour, Tag E. 1979. Chemotherapy of Parasitic Worms: New
Biochemical Strategies. Science 205(3):462-469. EXCELLENT REVIEW.
- Am J Vet Res 44(11):2186-2187, 1983. Avermectins
- J Neurochem 34:351-358, 1980. Avermectins
- Armour, J., "Modern anthelmintics for farm animals",
Chapter 10 in Pharmacological Basis of Large Animal Medicine,
eds. J.A. Bogan, P. Lees, and A.T. Yoxall, Blackwell Scientific
Publications, Boston, 1983. 565 pp.
- Karns, P.A. and D.G. Luther. (1984). A survey of adverse effects
associated with ivermectin use in Louisiana horses. JAVMA 185(7):
782-783.
- IVERMECTIN USE. Letter from Edward Boraski, Director, Technical
Services, MSD AGVET, Rahway, NJ. DVM NEWS MAGAZINE November 1984.
- IVERMECTIN USE. Letter from Duane N. Schulze, Practitioner,
Pigeon, MI. DVM NEW MAGAZINE, Fall 1984.
- Lynn'95: Lynn, Randy, [Title??? ] in Georgi's Parasitology
for Veterinarians, Ed. Dwight D. Bowman, W.B. Saunders, Philadelphia,
1995. 636.089696 G296p 1995
- Marshboom, Toxicology Applied Pharmacology 24:371, 1973.(MEBENDAZOLE)
- Roudebush, Phil. An Updated Guide to the Chemotherapy of Small
Animal Intestinal Parasites. Mississippi State University College
of Veterinary Medicine News Publication. Fall 1984
- Webster, L.T., Jr., Drugs Used in The Chemotherapy of Helminthiasis,
Chapter 40 in GG8th90.
- USPDI'94: United States Pharmacopeia Drug Information, 1994 edition
- Courtney & Roberson'95: Courtney, CH, and EL Robinson. Antinematodal Drugs, Ch. 45, in
Veterinary Pharmacology and Therapeutics, 7th edition, Ed. HR Adams,
Iowa State University Press, Ames. 1995.
New Refs not used in preparing these notes, yet.
- Medleau, Linda. 1994. Ivermectin ... , Vet. Med. August, p
770 - .
- Jetter, Swingle, Greek, Moriello. 1991. Treatment of Common
Parasiticidal Toxicities in Small Animals. Feline Practice 19(4):11
- .(July/Aug).
-
Random Notes that need to be included in appropriate place in
antiparasitic notes.
- From Lynn'95;
* p247 on Selectivity -- Ascarids are very sensitive to piperazines,
hookworms are refractory
* Most breeds of cattle & dogs tolerate phosphorus insecticides
-- Brahman cattle, Greyhound & Whippet dogs are likely to
be fatally intoxicated by such treatment.
- Lynn'95
* P248 -- Fenoxycarb -- marketed as BASUS to vets for flea control;
LOGIC as fire ant control
TORUS for cockroach control
- Lynn'95
*ON Insecticides
Federal Environmental Pesticide Control Act of 1972 (FEPCA).
FEPCA is administered by the EPA
Controls distribution, sales, and use of pesticides in the U.S.
State governments may establish stricter controls.
- .National Poison Control Center -- 800-548-2423.
- Reinemeyer, C.R., Faulkner, C.T., Assadi-Rad, A.M., Burr,
J.H., and Patton, S. 1995. Comparison of efficacies of three hearworm
preventatives against experimentally induced infections with Ancylostoma
caninum and Toxocara canis in pups. JAVMA 206(11):
1710-1715.
Not cited in these notes yet. Just added reference 5/31/95.
added also to antifilaricides
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Gordon L. Coppoc, DVM, PhD
Professor of Veterinary Pharmacology
Head, Department of Basic Medical Sciences
School of Veterinary Medicine
Purdue University
West Lafayette, IN 47907-1246
Tel: 317-494-8633Fax: 317-494-0781
Email: coppoc@vet.purdue.edu
Last modified
9:39 AM on 4/26/96
GLC