Epinephrine Auto-Injectors (EpiPen)

What is epinephrine?

Epinephrine is a drug used most often in emergency situations for animals (e.g., anaphylaxis, cardiopulmonary resuscitation [CPR]). Automatic injection devices for epinephrine (EpiPen®, EpiPen® Jr) are used off label in pets to treat anaphylactic (allergic) reactions that occur away from the veterinary hospital.

Many drugs are commonly used off label (extra label) in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is epinephrine given with an auto-injector?

• Epinephrine comes as a liquid solution in an auto-injector. The dose of epinephrine in the auto-injector is pre-measured for one injection into the muscle (IM). Your veterinarian may also provide pre-measured syringes of epinephrine to be used like an EpiPen.
• Follow your veterinarian’s directions and give this medication exactly as prescribed.
• Keep this medication easily accessible. Consider attaching it to the leash, crate, or something that always travels with the animal.
• Speed up absorption by gently massaging the site of the shot.
• When handling an epinephrine auto-injector, do not remove the blue safety release until ready to use and never place your hand or fingers over the orange tip, as this is where the needle comes out of the cartridge. 
• If you accidentally inject yourself, contact your physician immediately.

This medication should take effect immediately and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

Epinephrine is reserved for use in emergency situations. If you do not have epinephrine available and your pet starts having an allergic reaction, contact your veterinarian or emergency animal services immediately.

Are there any potential side effects?

It is recommended to contact your veterinarian after giving this drug for follow-up instructions. Epinephrine may cause the following side effects:

• Increased heart rate
• Nervousness, restlessness, and excitement
• Nausea and vomiting
• Increased blood pressure
• Tissue damage when injected repeatedly in the same area of tissue 

Are there any risk factors for this medication?

There are no absolute contraindications in life-threatening situations. USE WITH CAUTION in:

• Pets with diabetes
• Pets with high blood pressure
• Pets with an abnormal heart rhythm
• Pets with a low circulating blood volume
• Pets that are pregnant, nursing, or giving birth

Are there any drug interactions I should be aware of?

Several medications should be used with caution when given with epinephrine, including:

• Alpha-2-adrenergic agonists (e.g., detomidine, dexmedetomidine, medetomidine, xylazine)
• Alpha-adrenergic antagonists (e.g., phenoxybenzamine, phentolamine, prazosin)
• Antihistamines
• Beta-adrenergic antagonists (e.g., atenolol, propranolol, sotalol)
• Bronchodilators (e.g., albuterol, terbutaline)
• Levothyroxine
• Monoamine oxidase inhibitors (e.g., amitraz, selegiline)
• Nitrates (e.g., nitroglycerin)
• Oxytocin
• Phenothaizines (e.g., acepromazine)
• Phenylpropanolamine
• Tricyclic antidepressants (e.g., amitriptyline, clomipramine)

Be sure to tell your veterinarian about any medications (including vitamins, supplements, and herbal therapies) that your pet is taking before starting any treatment.  

Is any monitoring needed with this medication?

Follow up with your veterinarian after giving epinephrine and follow their instructions for monitoring.

How do I store epinephrine auto-injectors?

• Store auto-injectors at about 77°F (25°C).
• Do not store auto-injectors in the refrigerator or a car’s glove box.
• Do not expose auto-injectors to extreme heat or cold.
• Inspect the epinephrine periodically for particulate matter and discoloration. If you notice any, then throw the epinephrine away.
• Keep away from children and other animals.
• Check expiration date and refill before expiration date.
• Ask your veterinarian for specific disposal instructions. Do not flush medicines down the sink or toilet unless instructed to do so.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms.