Lesson 12

 

Administration of Medication to the horse

 

 

 

Oral Administration

 

 

1.   Drenching – administering liquid medication by mouth. This is not a preferred method usually because horses will often refuse to swallow many liquids, and in attempting to give it, it could go down the trachea. This could result in inhalation pneumonia, which is difficult to treat and often fatal.  Never squirt or forcefully administer a liquid substance orally with the horse’s head up.  Most medications are now formulated to pleasant tasting or in paste form.

  

2.   Stomach tube – Frequently used on the horse.  The stomach tube is passed up the nostril.  The horse must swallow the tube for it to travel down the esophagus on the left side of the neck and into the stomach.  This method is used when it is vital that the horse receive an oral medication or nutrition and he refuses to swallow voluntarily. This is a difficult procedure and should only be done by a veterinarian.

 

3.   Balling gun – Care and experience are required for this procedure.  It is usually easier for the horse to swallow pills that have been coated with something such as corn oil.  Bute pills can be given with a balling gun, but without proper technique the horse usually spits the pills out.

 

4.   Feed additives – Very common practice with many products, but remember the horse can be very picky.  Bute pills are usually crushed and added to the grain.  Molasses or corn syrup can be used to mix with bitter tasting medications for easier administration. Mentholatum (Vicks) can be rubbed in the nose in an attempt to mask the odor of the medication.

 

5.   Pastes & Gels – These formulations are becoming the most widely used means of administering medications and supplements to horses.  They are formulated in such a way that horses accept them readily. Be sure the horse has no feed in the oral cavity, as the medication will mix with it – enabling the horse to spit it out. 

 

 

 

Parenteral Administration

                      

 

1. Intramuscular

 

A.    Lateral neck muscles. (Above the spine, below the nuchal ligament and in front of the scapula, in a triangular area. Best for vaccines and smaller doses of medication (less than 20cc.)

 

B.    Heavy muscles of the buttocks (semitendinosis & semimembranosis) –This area is good for larger volumes of medication, however, it takes more practice to get efficient.

 

C.    Muscular part of the rump (gluteal region) as it slopes slightly downward – horse usually tolerates this area of injection very well.  The only negative, it is a bad area for an abscess to form from a contaminated injection.

 

 

It is imperative that a new sterile needle and syringe is used for each vaccination.  This is more important than cleaning the area.  Studies have shown cleaning the area with alcohol has little effect.  Should you want to clean the area, the steps are: shave the hair, scrub with an antiseptic soap, which must remain on the site for two minutes, and then rinse with alcohol.

 

There are several methods of inserting the needle.  Have your veterinarian show you, and then allow you to do it under his/her guidance.  One method is to place the needle into the muscle, and then attach the syringe and complete the injection.  In this way, you can make sure blood does not flow from the needle.  If blood does flow, you must pull the needle out and reinsert. Another method is to insert the needle while attached to the syringe, pull the plunger back slightly and look for blood. If blood appears, move to a different location. 

 

     Medications intended for intramuscular use that are inadvertently injected into the venous or arterial circulation can cause a severe reaction and sometimes-even death.

 

     Needle size is usually 1-½ inches long and 18 to 20 gauge.

 

     Excessive movement of the horse after the needle is in place can result in trauma to the area.

 

 

2. Intravenous – I.V. injections are given in the Jugular vein.  Intravenous injections in the horse are a common way of administering injectable medication, but must be done by someone who is well trained in the technique and familiar with the medication being used.  Beware of the “know it all” around the barn area who wants to give your horse a “bute” shot.  Bute and many other I.V. injectables can be very caustic if not given correctly into the vein, and can cause long term and serious problems if not done properly.

 

 Improper technique can sometimes cause a medication to be injected into the carotid artery causing immediate death to the horse.   Phenylbutazone (bute) should only be injected intravenously.

 

 A 1 ½ inch 18 gauge needle is usually used for I.V. injections.

 

 Common technique that your veterinarian will follow: hold off jugular vein in lower part of jugular furrow in order to distend the vein with blood so you can identify it.  Insert needle into vein so it is well placed and blood is flowing, then attach syringe.  Pull back on syringe to be sure you are still in the vein, then administer the medication slowly.  Draw back on syringe when you are finished administering medication to recheck placement and flush needle of medication.

 

 

3. Intravenous catheters – Used when large volumes of fluids are to be given intravenously. Routinely done on very ill horses.  As an owner you may be called upon to monitor intravenous fluid administration.  Important points in monitoring I.V. fluid administration once a catheter has been placed are:

 

A. Usually the catheter is positioned in a downward direction.

 

B. Fluids should be flowing at an even rate, which you can determine by making sure the air bubbles are flowing up in the fluid bottle.

 

C. If smooth flow is interrupted (no air bubbles) immediately close off valve to prevent further flow of medication. If you note a swelling beginning to appear around the entrance of the catheter (the catheter has moved out of the vein) immediately close off flow of medication.

 

D. The horse is okay if he is hooked up to an I.V. and the lines are filled with fluid, but it has been closed off.

 

E. If you are using an air pump or other positive flow device and the fluids are either accumulating under the skin or are running out, immediately close off the flow or at last resort rapidly pull out I.V. catheter.  It can always be replaced.  The idea is to prevent the horse from having air injected into his vein, or a large accumulation of fluid out of the vein.

 

F. If you have given a horse a large volume of medication I.V. that took more than 30 seconds to give, it is always a good idea to keep the horse’s head up for 4 or 5 minutes and keep slight pressure on the injection site to prevent the horse from bleeding back. Even a 10cc shot in the vein can bleed back if the horse lowers his head to graze or eat right after the shot.

 

 

 

4.  Intra-articular injections – The injection of a medication directly into a joint. This is a commonly done procedure in horses to treat a joint directly.  This is a technique which would unlikely be performed by anyone other than your veterinarian.  It must be done with the utmost attention to sterility, because a joint infection from improper technique could have devastating affects on the horse. The injection site is usually scrupulously prepared and a needle is place into the joint without the syringe. Excess synovial fluid is allowed to flow out of the joint where it can be visually examined for abnormalities, then a syringe is attached to the needle and the medication is injected directly into the joint.  A sterile gauze pad or disinfectant pad are placed over the area of injection and is secured by a temporary bandage. Oftentimes an injection of Bute or Banamine is also given I.V. to prevent a possible joint flare up.

 

 

5.  Subcutaneous (under the skin), and intradermal (between the epidermis and dermis) injections in the horse are rare.

 

 

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*No medications should be given to a horse without the advice of a veterinarian.