(1989; 60 pages) [French]
Epinephrine (for use with local anaesthetics)
Group: additive to local anaesthetic agents
Injection: 1 mg (as hydrochloride) in 1-ml ampoule
Epinephrine is a sympathomimetic agent that activates both α- and β-adrenoceptors. It is secreted together with norepinephrine by the adrenal medulla in response to stress. Epinephrine is transient in its effect when administered parenterally because it is rapidly metabolized.
To retard systemic absorption of infiltrated local anaesthetics.
Dosage and administration
The addition of epinephrine 5 micrograms/ml (1:200 000) as a vasoconstrictor to local anaesthetic solutions slows systemic absorption and prolongs the anaesthetic effect. In dental surgery, in which small volumes are injected, concentrations of 12.5 micrograms/ml (1:80 000) are commonly used.
Epinephrine should not be used in ring block of digits or the penis or in other situations where there is a danger of local ischaemia.
Solutions containing epinephrine should be used with particular caution in patients with hypertension, atherosclerotic heart disease, cerebral vascular insufficiency, heart block, thyrotoxicosis or diabetes since severe and sustained variations in blood pressure may occur.
The risk of cardiac dysrhythmias is increased when epinephrine is administered to patients receiving halogenated hydrocarbon anaesthetic agents (such as halo-thane and trichloroethylene), digitalis glycosides, quinidine, tricyclicantidepressants or thyroid hormones.
An abrupt rise in blood pressure and dysrhythmias may be counteracted by propranolol or other β-adrenoceptor-blocking agents.
Epinephrine injection should be stored protected from light.