Chapter Thirteen

Drug Therapy and Common Diseases of Laboratory Animals

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Drug Therapy

Analgesics = pain relieversaspirin, Tylenol®, morphine, buprenorphine

Anesthetics = make animals unconscious.methoxyflurane, halothane, isoflurane, ketamine,

pentobarbital

Antibiotics = reduce no. of microorganisms. penicillin, tetracycline, erythromycin

Anti-inflammatory drugs Cortisone - aka steroids reduce swelling, itching & pain

prednisone, dexamethasone and many other related drugs

NSAIDs have fewer side effects than steroids. aspirin, ibuprofen, ketoprofen

Antiparasitics = kill parasites living on or in host.

Drug Therapy II

Anthelmintics - eliminate worms thiabendazole, piperazine & ivermectin

Insecticides - kill parasites on skin & furavailable as sprays, liquids, powders, dips... carbaryl, pyrethrins & various organophosphates

Antiprotozoals - kill protozoan parasitesMetronidazole is a commonly used antiprotozoal.

Tranquilizers - used before anesthetic to reduce amount of anesthetic neededacepromazine, diazepam, xylazine

Drugs could alter experimental results.Health programs focus on prevention, not treatment.

Methods of Drug Dosing

Certain anesthetics inhaled as a vapor or gas.Blood vessels in lungs absorb vaporized anesthetics &

carry them to brain, where primary action occurs.

Topical drugs or chemicals applied directlycreams, ointments, aqueous solutions, tinctures,

powders & spraysAquatics treated by adding medication to tank.

Oral drugs mixed in feed or water or inserted directly into mouth. Instilled into esophagus or stomach by gavage.

Suppositories for insertion in rectum of lg. animalDissolved & taken into body through membranes.

(Images) Oral DosingOral Dosing

Methods of Drug Dosing II

Parenteral = administration of drugs by means other than through gastrointestinal system.Allows drugs to enter bloodstream more directly.

Technique chosen depends on: speed of absorption its effect on the tissuesvolume to be injected technical skill required

Intramuscular (IM) - injected into large muscle mass It is absorbed into the blood vessels in muscle around

injection site.

Methods of Drug Dosing III

Intravenous (IV) - into a large vein Subcutaneous (SC or SQ) - into area between skin

and underlying musculature Intradermal (ID) - into dermal layer of skin, slow

systemic absorption takes place Intraperitoneal (IP) - into abdominal cavity

Prevent accidental injection into internal organs. IP injection used in rodents which lack sizeable muscles

or blood vessels for injection.

Intracardiac (IC) - directly into heartUsed when drug must be rapidly administered.Risk that pericardium or heart muscle could be lacerated.

(Images) Parenteral Dosing

Intracardiac (IC)

Intraperatoneal (IP)

Intradermal (ID)

Subcutaneous (SC or SQ)

Intravenous (IV)

Treatment Record Keeping

Helps plan strategies to treat abnormal conditions or prevent disease outbreaks.Helps investigators interpret & analyze test results.

Supports personal interpretations w/ specific data. Health report form, treatment form, surgery form, log

book, animal’s health record If a mistake is made, a SINGLE line is used to cross

out mistake, & technician places initials beside error. ALL entries in a record should have

correct date & initials of person

making entry.

Diseases of Laboratory Animals

Some facilities have particular animal colony health problems often identified in that facility.

Technicians should review these common health problems w/ facility veterinarian.

Review signs, treatments & reporting procedures to ensure all common disease problems are promptly noted & appropriate animal care provided.

Diseases of Laboratory Animals II

Signs of skin disorders caused by trauma, microbes or infestation w/ external parasites are alopecia, pruritus, & rough hair coat.

Signs of respiratory diseases caused by bacterial or viral microbes are coughing, discharge, dyspnea, listlessness, sneezing.

Signs of gastrointestinal disease commonly associated with parasites, toxic chemicals & microbial infection are anorexia, constipation, diarrhea, listlessness, loss of weight, prolapse, stunted, vomiting.

Diseases of Laboratory Animals III

Physical trauma often a result of animal fights or accidents i.e. bleeding, paralysis.

Metabolic disturbances caused by genetic factors, nutritional problems, and toxic substances or other less obvious factors are anorexia, listlessness, loss of weight.

Additional Reading

Fox, J.G., B.J. Cohen, and F.M. Loew (eds.) Laboratory Animal Medicine. Academic Press, Inc., New York, NY. 1984.

Harkness, J.E. and J.E. Wagner. The Biology and Medicine of Rabbits and Rodents, 4th ed. Lea and Febiger, Philadelphia, PA. 1995.

Hrapkiewicz, Karen, Leticia Medina, and Donald D. Holmes. Clinical Laboratory Animal Medicine: An Introduction, 2nd Ed. Iowa State University Press, Ames, IA. 1997.