Routes of Drug Administration

1. Routes of Drug Administration • I.M. (intramuscularly) • Use at least a one inch needle to assure that the drug is placed deep in the muscle for proper absorption. • The diameter or gauge (g) of the needle should be as small as possible to prevent the drug from running up the needle tract and down the side of the animal. • This route allows for the second fastest rate of absorption • Site of injection is important, particularly in food producing animals, when possible use the muscles in the neck. Injection site abscesses can develop.

2. I.V. (Intravenous) • Provides the fastest route of absorption of the drug • In large animals use a 1.5 inch X 16g needle • In large animals the jugular vein in the neck is most often used • Always read the label, some drugs cannot be administered I.V. • Drugs should be close to body temperature before administration • Drugs should be administered slowly (drip) when given I.V.

3. Sub-Q (subcutaneous) • Drug administered between the skin and muscle • Injections or implants • Provides for a slower , sustained release of the drug • Less likelihood of causing tissue damage at the injection site in food producing animals • Can cause permanent knots that disfigure the animal, sometimes lessening its value.

4. I.D. (intradermal) • Drug injected into the skin • Very slow rate of absorption • Ex. Tuberculosis skin test • Use 20 to 26g needle

5. I.P. (intraperitoneal) • Drug injected directly into the peritoneal cavity • Slow absorption rate • In large animals a 1.5in X 16g needle I generally used • Often used in combination with I.V. injections to prolong the availability of the medication to the animal ex. Milk fever- Cal-Dex given both I.V. and I.P.

6. I.R. (intrarumenal) • Similar to I.P. ,but into the rumen (1st stomach in ruminant animals) • When the needle is properly placed gas wiil flow out • Can only be accomplished on the left side of the animal

7. I.M.F. (intramammary infusion) • Drug is injected into the teat canal using a plastic teat infusion canula • Used in the treatment of mastitis

8. I.N. (intranasal) • Drug is squirted up the nostril • Some vaccines can be administered this way ex. Nasogen for IBR vaccination • Many pharmaceutical companies are currently developing vaccines and other drugs that can be administered I.N. to avoid injection site problems and to satisfy animal rights activist.

9. I.U. (intrauterine infusion) • Drug in infused into the uterus by passing a pipette through the cervix • Often used to treat metritis (uterine infection)

10. Topical • Drug applied to the skin or surface of the body • ex. Salves, ointments, pour-on wormers, dusts, etc.

11. Oral (drench) • Drug administered through the mouth in the form of a bolus (pill) or liquid • Liquids or pastes can be placed in the mouth and the animal allowed to swallow them or a stomach tube can be used to place the drug directly in the digestive system