Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

   5.1 Pharmacodynamic properties
Pharmacotherapeutic group: adrenergic and dopaminergic agents, adrenaline 
ATC code: C01 CA 24

Adrenaline is a direct acting sympathomimetic agent, which exerts effects on both α and β adrenoceptors. It has more pronounced effects on β than on α adrenoceptors, although α effects prevail at high doses.

The effects of adrenaline include increased rate and force of cardiac contraction, cutaneous vasoconstriction and broncho-dilatation. With higher doses, stimulation of peripheral α receptors results in an increase in peripheral resistance and in blood pressure.

Pharmacokinetic Properties

5.2 Pharmacokinetic properties
Pharmacologically active concentrations of adrenaline are not achieved following oral administration as it is rapidly oxidised and conjugated in the gastrointestinal mucosa and the liver. Absorption from subcutaneous tissue is slow due to local vasoconstriction; effects are produced within 5 minutes. Absorption is more rapid after intramuscular injection than after subcutaneous injection.

Adrenaline is rapidly distributed into the heart, spleen, several glandular tissues and adrenergic nerves. It readily crosses the placenta and is approximately 50% bound to plasma proteins.

Adrenaline is rapidly inactivated in the body, mostly in the liver by the enzymes catechol-O- methyltransferase (COMT) and monoamine oxidase (MAO). Most of a dose of adrenaline is excreted as metabolites in urine.

After intravenous administration, the plasma half-life is about 2-3 minutes.