Administration of Medication

Oral Medications Oral medications come in multiple forms including powder, tablet, paste, and liquid Feed additives – Oral medications added to the horse’s feed, usually grain Pills should be crushed instead of whole Medications often have an objectable taste increasing the chance of the horse not eating the food

Oral Medications

Nasogastric Intubation Use of a nasogastric tube can cause trauma Nosebleeds may happen if horse throws its head around during the procedure The bleeding usually stops on its own – unless the horse has a bleeding disorder

Nasogastric Intubation Into the esophagus may be necessary to sedate the horse It may be necessary to warm the tube if it is cold Stand on the side of the horse to help avoid being struck

Nasogastric Intubation Premeasure the tube Keep the tube from moving around When administering liquid, it should never be forced Horse stomach: 4 – 5 gallons

Nasogastric Intubation one gallon at a time This can be repeated in 30 mins. if necessary Tubes come in a variety of sizes Lube the tube

Nasogastric Intubation

Injections IM injections – The most commonly used and accessible muscles are the brachiocephalicus, pectoral, gluteal, semitendinosus, & triceps brachii Maximum volume depends on the muscle used General rule = 15mL in one location (larger muscle body) & 5 – 10mL in smaller muscle bodies (pectoral) The maximum volume can be increased by 5mL in larger draft breeds

Injections Lateral Cervical – The most common site for IM injections –Pinch & Stick –This site is contraindicated in nursing foals

Injections

Pectoral Muscle – Used for smaller volumes –Site has good ventral drainage Triceps Muscle – Generally used when all other common sites have been exhausted –Not suitable for large doses

Injections

Gluteal Muscle – Consists of several muscle bellies in the rump area covered by thick, tight skin –More force is required to penetrate the skin –“Thump thump stick”

Injections

Semitendinosus Muscle – Better for smaller amount of medications, less than 10mL –The injection is given at the most prominent area of the buttocks as viewed from a lateral position –Horses are prone to kicking when the needle is inserted, never stand behind the horse

Injections

IV Injections Jugular Vein – The most common peripheral vein used –The carotid artery and vagosympathetic nerve trunk lie deep to the jugular vein Both structures run parallel to the jugular vein It is possible to puncture either structure if the jugular vein is gone through or missed

IV Injections

Large hematomas that can last for weeks may be the result of a carotid stick If medication is injected into the carotid a large bolus of medication is delivered to the brain –This may cause the horse to seizure, collapse, or go into cardiac or respiratory arrest –Injecting into the carotid should be avoided at all costs

IV Injections Whenever possible the vein should be accessed in the cranial groove of the jugular groove –There is more muscle between the carotid and the jugular in this location –Need to be able to tell the difference between arterial and venous blood –Divide the neck into thirds and use the upper third

IV Injections

IV Injections A ccessory Veins : –Lateral Thoracic –Cephalic –Saphenous –Coccygeal Generally a 1 inch needle is needed when using these veins

IV Injections Lateral Thoracic – Runs along the ventrolateral aspect of the thorax –The blood flows cranially toward the brachial vein Cephalic Vein – Located on the forelimb – Difficult to access in a standing horse Saphenous Vein – Located on the hind limb –Difficult to access in the standing horse

IV Injections

Coccygeal Vein – Lies on the ventral midline of the tail –small volumes of nonirritating substances –Swelling or perivascular scarring may occlude the coccygeal artery – tail may slough off

IV Injections

SQ Injections Most common site is under the skin of the lateral neck Technique is the same as small animals SQ route is not suitable for larger volumes, therefore this site is not used for fluid therapy

SQ Injection

IV Catheterization Most common site used for IV catheter placement is the jugular vein, followed by the lateral thoracic vein, and then the leg veins When choosing an IV catheter consider: –size of the animal –length of time the catheter will remain in place –length of the catheter –function of the catheter

IV Catheterization Cutdowns are rarely performed in the horse Short catheters (2-3 inches) are not suitable for long term use. –Can easily be dislodged by the movement of the horse –Can perforate the vein – shorter = stiffer

IV Catheterization - Stiffness –Polypropylene catheters are available in larger gauges, but reactivity = not good for long term use, usually no more than 24 hours –Teflon and polyurethane catheters fall into the moderate range for both reactivity & stiffness 7 days These are the most popular catheters

IV Catheterization Silicone is the most pliable and least reactive –4 weeks –Only available in smaller diameters Not a good choice when larger volumes are needed

IV Catheterization Immediately after inserting the catheter and placement is confirmed a cap needs to be placed. Once the IV cap is in place the catheter needs to be flushed w/ a heparin flush to prevent clotting w/ in the catheter or cap Secure catheter to skin CATHETER CARE!!!

IV Catheterization IV catheter should not be used to obtain blood samples Once the catheter has been removed pressure & antibiotic ointment should be applied to the site

IV Catheter

IV Catheterization - Thrombophlebitis Inflammation of a vein with concurrent thrombus formationInflammation of a vein with concurrent thrombus formation The thrombus formation may begin on the catheter itself or on damaged areas of the vein walls created by insertion or use of the catheter Once thrombus formation begins it may grow large enough to completely obstruct blood flow This can situation can be complicated by bacterial growth (septic thrombophlebitis)

Enema Administration This once popular route for large animals is rarely utilized today Mainly used in foals to help aid in the passage of meconium Fluids should never be forced – may rupture the rectum An average size adult horse (1000#) can be given on average 1 – 3 gallons of liquid