Medication Administration in Cats and Dogs CTVT pages 588-590

Routes of Medication Administration Oral (PO) Aural Sublingual Topical Via feeding tube Topical ophthalmic Esophagostomy Transdermal Gastrostomy Intranasal Jejunostomy Inhalation Orogastric intubation Nebulized or volatilized Nasogastric intubation Intratracheal Rectal (PR)

Parenteral Routes: administered with a needle and syringe Intradermal (ID) Subcutaneous (SC or SQ) Intramuscular (IM) Intravenous (IV) Intraosseous (IO) Intraperitoneal (IP) Intra-arterial (IA) Epidural/subdural Intracardiac (IC) Intramammary

Route Depends on Many Factors Patient Factors Health conditions Symptoms Absorption rate of drug required Temperament Ease of administration for client Drug Factors Type of medication/fluid Formulation of drug Cost Systemic vs. local effect desired

Other Factors to Consider Does this medication require that special precautions be followed during administration (i.e. gloves, mask)? Examples? Potential side effects? Pain from injection Vomiting/GI upset/constipation

Comparison of Common Parenteral Routes of Drug Administration Intramuscular 90° Intravenous 25° Subcutaneous 45° Intradermal 10°–15° Epidermis Dermis Subcutaneous tissue Muscle

Mini A&P Review of Skin Layers The skin is made up of three layers: the epidermis, dermis, and subcutaneous layers The epidermis is several cell layers thick and does not contain blood vessels. Its thickness varies greatly from region to region in any animal and varies from species to species. The dermis is composed of blood vessels, lymph, nerve fibers, and accessory organs of the skin (glands and hair follicles). The subcutaneous layer (hypodermis) is composed of connective tissue and contains a large amount of fat. Muscle lies underneath all of these layers

Before the Injection Gather supplies Needles Syringe Medication to be injected Proficient person to restrain the animal For venipuncture only: Cotton ball with alcohol Hydrogen Peroxide (optional)

Syringes are available in various sizes (even more than this)

Needles Needle gauge is determined by: Consistency of drug Route of administration Patient size At least two needles are required One to draw up the medication One to administer the medication Why is this?

Process for Changing Needle Draw up exact amount of drug Can use smallest needle available Aspirate all drug into the syringe (out of the needle) Hub loss- Remove needle and replace with appropriate needle Carefully ensure all air is out of the syringe by slowly depressing the plunger.

Injectable Drugs Supplied as: May be stored in: Sterilized solutions Powders that must be reconstituted with sterile solution May be stored in: Vials (single or multi-dose) Ampules Fluid bags

Intradermal Injections Common use of ID route: Desensitize skin Allergy skin testing Skin is usually shaved before performing an ID injection Drug is not dispersed throughout the body

Intradermal Administration

ID Injection Procedure A fold of skin is lifted or skin is pulled taught and a 25- to 27- gauge needle attached to a syringe is inserted with the bevel up into the dermis. If allergy testing: A 0.1 ml volume of allergen is injected. If locally anesthetizing skin: dose of drug The injection site will look like a translucent lump if the injection is performed correctly.

Subcutaneous Injections Easiest route to perform technically Common use of SQ route: Vaccine administration Fluid administration Pain medications, antibiotic injections, Insulin Absorption rate is slow compared to other routes May be slower in obese animals Some substances are harmful if injected SC Example:

Subcutaneous Administration

SC Injection Sites Preferred site for most SC injections is the dorsolateral region from the neck to the hips. The dorsal region of the neck and back should be avoided for drug administration. Cat vaccines: the _______________________ should be avoided because of the incidence of vaccine-induced tumors. Feline vaccinations should be administered in as distal a portion of an extremity as possible.

SC Injection Sites

SC Injection Procedure Fold of skin is tented and the needle is inserted at the base of the tent. Insert needle as if walking INTO the tent Aspirate Why? After injection, briefly massage skin to facilitate drug distribution.

Skin Tent

Intramuscular Injections Appropriate route for injection of small volumes of medication. Common uses of IM route: Anesthetics/sedatives Convenient route of administration for fractious animals Pain medications Heartworm treatment Generally, more painful for animals than SC or IV. Why?

Intramuscular Administration

IM Injection Sites Drugs are most often administered in the: Lumbosacral musculature lateral to the dorsal spinous processes Semimembranosus/ semitendinosus muscles of the rear leg In the hind limb: needle should enter the lateral aspect of the muscle and be directed caudally Why?

Avoid the sciatic nerve!

IM Injection Sites Deep IM injections in the third to fifth lumbar region of the ___________________ are used to administer adulticide heartworm treatment (Immiticide®).

IM Injection Procedure Isolate the muscle between the fingers and thumb. A 22 to 25 gauge needle attached to a syringe is embedded in the muscle at a ______ angle. As with a SQ injection, the needle hub is checked for blood before administration of medication to make certain a vessel is not inadvertently penetrated. How did we do this? Once in the muscle, inject the medication slowly. Massage the site for a few seconds after the injection to help distribute the substance if possible. Exception:

Complications from IM Injection Tissue trauma Pain at injection site Nerve damage

Intravenous Administration Drugs and/or fluids may be injected directly into a vein or through an IV catheter. IV route produces an immediate response Usually given slowly Common use of IV route: Inducing anesthesia Chemotherapeutic agents Anti-convulsant drugs Irritating drugs Emergency/resuscitation drugs Large amounts of _________ needed Requires new needle for administration

IV Injection Sites CAT DOG Cephalic Medial saphenous Femoral Cephalic Lateral saphenous Note: The jugular vein is used to administer injections in small animals IF an intravenous jugular catheter is in place.

Cephalic Vein

Femoral/Medial Saphenous Vein (cat)

Lateral Saphenous Vein (dog)

IV Injection Instructions Expel all air bubbles from the syringe prior to inserting into the vein. Restrainer should occlude the vessel with digital pressure or use a tourniquet. Grasp the extremity and pull the skin taut in a distal direction. Swab the skin and hair with an alcohol-soaked cotton ball (go with the fur). Insert a 20- to 25- gauge needle, bevel up into the vein.

IV Injection Instructions (cont’d) Usually blood enters the hub of the needle at penetration of the vein (flash), BUT, placement is confirmed by aspirating. What should we see? Venipuncturist: communicate to restrainer “I’m in” Restrainer: release pressure from the vein Inject the medication into the vein. If large volume of drug or movement of needle: Communicate with restrainer and remove needle Apply firm pressure to the injection site until hemostasis/coagulation occurs

If Using a Tourniquet Most common: Nye Tourniquet or Penrose drain/rubber material Can be very dangerous if used improperly Goal is to visualize and palapte vein. Must be able to remove before injecting!

Possible Complications with IV Injections Injecting drug outside of vein Hematoma formation Intra-arterial injection of drug Hitting a nerve (pain, lameness, paralysis) Air-embolus Phlebitis Septicemia