Epinephrine

Epinephrine – usually called adrenaline in everyday life – is a hormone and neurotransmitter formed in the adrenal medulla. Anyone who has ever experienced how a dog collapses after an insect sting knows: this messenger substance decides between life and death. Epinephrine controls the classic fight-or-flight response, acts on the cardiovascular system and simultaneously influences metabolism – which is why it is considered the most important emergency medication in veterinary medicine.

What epinephrine does in the body

As soon as stress or a life-threatening situation occurs, the body releases epinephrine. The goal: to mobilise energy within seconds and ramp up performance. An overview of the most important effects:

Heart rate increases: Epinephrine drives the heart – heart rate and contraction strength increase. Muscles and organs are better perfused, oxygen transport improves noticeably.

Airways widen: In the bronchi, epinephrine causes relaxation of the smooth muscle, increasing airflow. This is particularly crucial in emergency situations where breathing is already restricted – such as with allergies or asthma.

Blood sugar rises: The liver releases glucose from glycogen stores. Blood sugar shoots up, the body has immediately available energy – turbo on demand, so to speak.

Blood vessels constrict: In the skin and digestive tract, epinephrine causes vasoconstriction. Blood flow is deliberately redirected to the heart, lungs and brain – exactly where it is needed in an emergency.

Use of epinephrine in dogs

In veterinary medicine, epinephrine ends up almost exclusively in the emergency drawer – and rightly so. It acts quickly, strongly and is often the only alternative in acute life-threatening conditions.

Anaphylactic shock: Anaphylaxis is the ultimate veterinary nightmare: the dog struggles to breathe, blood pressure plummets, and shock looms. Epinephrine dilates the bronchi, increases heart rate, constricts blood vessels, and thereby stabilises pressure. Additionally, it can inhibit the release of further allergy mediators.

Cardiopulmonary resuscitation (CPR): If the heart stops, epinephrine is administered to restart it. It demonstrably increases the chances of successful resuscitation.

Asthma and bronchospasms: In severe attacks or allergy-induced breathing difficulties, epinephrine can relieve constricted airways and literally give the dog room to breathe.

Shock states: If organ perfusion is generally impaired, epinephrine can raise blood pressure and ensure the supply of vital structures – buying time until the cause is treated.

Acute glaucoma attack: In cases of suddenly high intraocular pressure, veterinarians sometimes use epinephrine to lower the pressure and prevent permanent damage to the optic nerve.

How epinephrine is administered

Depending on the emergency situation, veterinarians choose different routes of administration:

Intravenously (IV): In cardiac arrest, every second counts. IV administration delivers the active ingredient most quickly to where it is needed.

Intramuscularly (IM) or subcutaneously (SC): For anaphylaxis, injection into the muscle or under the skin is common – it acts quickly but is easier to perform than an IV puncture in hectic moments.

Inhalation: In bronchospasms or asthma, epinephrine can be administered as an aerosol directly into the airways. The effect is localised without placing such a heavy burden on the circulatory system.

Side effects you should know about

Epinephrine is not a gentle remedy. Especially in high doses or with prolonged use, it can noticeably stress dogs:

Heart rate and blood pressure rise excessively: The stimulating effect can lead to arrhythmias – in the worst case, even a heart attack. Therefore, continuous monitoring is mandatory.

Anxiety and restlessness: The sympathetic nervous system is running at full throttle. Many dogs appear nervous, tremble, or are hard to calm down.

Blood pressure drop after the effect wears off: As epinephrine subsides, blood pressure can plummet rapidly. Then renewed monitoring – and sometimes follow-up treatment – is necessary.

Nausea and vomiting: Some dogs react with gastrointestinal complaints: nausea, vomiting, or diarrhoea are possible.

Overdose: Too much epinephrine can trigger serious heart problems, in extreme cases cardiac arrest. Accuracy in dosing is therefore not optional but a basic requirement.

What veterinarians must pay attention to

Epinephrine saves lives – but it is not a remedy to be used lightly. In dogs with pre-existing heart problems or high blood pressure, particular caution is advised. The dosage and route of administration always depend on the severity of the situation and the individual health status of the animal. After each dose: close monitoring until the dog is stable and no after-effects occur.