Administration of Medications
Oral (PO)-Oral medicine can be dissolved or crushed and mixed into the feed or directly into the mouth with a syringe.¬† We normally dissolve the medicine in a syringe in water and then give it to them like a paste wormer.¬† After insuring that the mouth is empty, the tip of the syringe should be inserted at the side of the mouth, pointing up towards the back of the tongue.¬† Once given, holding the horses head up which keeps the mouth shut helps prevent them from spitting it out.
It takes approximately 2 hours for absorption when a drug is given orally.
Subcutaneous (SQ) administration is injection directly under the skin.¬† Usually given on the side of the neck.¬† A fold of skin is lifted and the needle is slid just under the skin.¬† Draw the plunger back to insure there is no blood aspirated.¬† If there is blood, redirect and reconfirm the proper location.¬† This route is limited to a few select medications.
Intramuscular (IM)-Most common sites for IM injections include the neck and the rump.¬† When administrating IM injections, once the needle is inserted one must draw back on the plunger to check for evidence of blood in the syringe.¬† If this happens, it reflects the location of the needle within a blood vessel and not within muscle tissue. If there is blood, simply redirect needle and aspirate a second time to confirm the location.¬† Certain medications if accidentally injected into a vessel will result in a seizure.¬† The most notorious drug associated with adverse reactions such as seizures is Procaine Penicillin G.¬† The reaction to penicillin occurs within seconds to minutes of the injection.¬† Additional complications associated with IM injections include injection site reactions that often begin as local swelling.¬† These may be painful and can develop into an abscess.
IM injected medications take effect slower then IV meds but more rapidly then oral medications
Intravenous (IV)-Intravenous injections may be given by needle directly into the jugular vein or through a catheter.¬† Potential complications associated with IV injections can result of from inadvertant insertion of the needle into the carotid artery instead of the vein.¬† This will result in an immediate seizure and sometimes death of the horse.¬† Extravascular injection into the surrounding soft tissues (instead of the vein) can lead to pain, swelling and ceratin drugs can cause sloughing of the tissues.
Results with the intravenous injection ranges from 30 seconds with sedatives to 30 minutes with Banamine. ¬†Note: there are many medications that cannot be given IV and others that can only be administered by this route.