Chapter Thirteen

1. Chapter Thirteen Drug Therapy and Common Diseases of Laboratory Animals

2. ALAT Presentations Study Tips • If viewing this in PowerPoint, use the icon to run the show (bottom left of screen). • Mac users go to “Slide Show > View Show” in menu bar • Click on the Audio icon: when it appears on the left of the slide to hear the narration. • From “File > Print” in the menu bar, choose “notes pages”, “slides 3 per page” or “outline view” for taking notes as you listen and watch the presentation. • Start your own notebook with a 3 ring binder, for later study!

3. Drug Therapy • Analgesics = pain relievers • aspirin, 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.

4. Drug Therapy II • Anthelmintics - eliminate worms • thiabendazole, piperazine & ivermectin • Insecticides - kill parasites on skin & fur • available as sprays, liquids, powders, dips... • carbaryl, pyrethrins & various organophosphates • Antiprotozoals - kill protozoan parasites • Metronidazole is a commonly used antiprotozoal. • Tranquilizers - used before anesthetic to reduce amount of anesthetic needed • acepromazine, diazepam, xylazine • Drugs could alter experimental results. • Health programs focus on prevention, not treatment.

5. 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 directly • creams, ointments, aqueous solutions, tinctures, powders & sprays • Aquatics 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. animal • Dissolved & taken into body through membranes.

6. (Images) Oral Dosing Oral Dosing

7. 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 tissues • volume 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.

8. 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 heart • Used when drug must be rapidly administered. • Risk that pericardium or heart muscle could be lacerated.

9. (Images) Parenteral Dosing Intravenous (IV) Subcutaneous (SC or SQ) Intradermal (ID) Intraperatoneal (IP) Intracardiac (IC)

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.