Epinephrine stimulates both the alpha- and beta-adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. It is also used as a vasoconstrictor, cardiac stimulant, or bronchodilator to counter allergic reaction, anesthesia, and cardiac arrest. Epinephrine is used to treat severe allergic (anaphylactic) reactions because it can prevent or minimize the effects of histamine. It is also an antiglaucoma agent.

Mechanism

Epinephrine is available in nebulized racemic dosage form for inhalation.Intoxication from catecholamine usually results from iatrogenic overdoses, accidental intravenous administration, and the injection of solution intended for nebulization. High concentrations of dopamine present inside of a cell than there are vesicles to store it in, oxidative stress can occur and cause damage or death to the cell. It is thought that dopamine overload causes biochemical damage to cellular mitochondria, that provide the cell with all of the energy it requires to function, resulting in death of the cell. Catecholamines produced circulatory changes that reversed propofol anesthesia in animal models.

Uses

As a medication, Epinephrine is used to treat a number of conditions including anaphylaxis, cardiac arrest, and superficial bleeding.Inhaled adrenaline may be used to improve the symptoms of croup.It may also be used for asthma when other treatments are not effective. It is given intravenously, by injection into a muscle, by inhalation, or by injection just under the skin.Common side effects include shakiness, anxiety, and sweating. A fast heart rate and high blood pressure may occur. Occasionally it may result in an abnormal heart rhythm. While the safety of its use during pregnancy and breastfeeding is unclear, the benefits to the mother must be taken into account.

A case has been made for the use of adrenaline infusion in place of the widely accepted treatment of inotropes for preterm infants with clinical cardiovascular compromise. Although there is sufficient data which strongly recommends adrenaline infusions as a viable treatment, more trials are needed in order to conclusively determine that these infusions will successfully reduce morbidity and mortality rates among preterm, cardiovascularly compromised infants.

Adverse effects

Adverse reactions to adrenaline include palpitations, tachycardia, arrhythmia, anxiety, panic attack, headache, tremor, hypertension, and acute pulmonary edema. The use of epinephrine based eye-drops, commonly used to treat glaucoma, may also lead to buildup of adrenochrome pigments in the conjunctiva, iris, lens, and retina.

Rarely, exposure to medically administered epinephrine may cause Takotsubo cardiomyopathy.

Use is contraindicated in people on nonselective β-blockers, because severe hypertension and even cerebral hemorrhage may result.