How and When Is Epinephrine Used As A Vasoconstrictor in Local Anesthetics?
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Epinephrine in LA (Adrenalin®)
Epinephrine is a an alpha-/beta-agonist that is administered as an adjuvant in local anesthetic cartridges.
Epinephrine is also used as an emergency drug for treatment of anaphylactic reaction and a vasoconstrictor to decrease systemic absorption of local anesthetics and to increase the duration of anesthetic action. The use of Epinephrine may decrease superficial hemorrhage.
- May be used in concentrations of 1:500,000 to 1:50,000.
- 1:100,000 and 1:200,000 is used most commonly in a typical 1.8 ml local anesthetic dental cartridge; this is equivalent to 0.018 to 0.009 mg of epinephrine per cartridge.
- Submucosal Injection as part of a local anesthetic cartridge
- Dosage varies depending on the procedure, area to be anaesthetized, vascularity of tissues, and patient’s tolerance and physical condition.
- Depending on the local anesthetic with which epinephrine is combined, maximum recommended doses of the local anesthetic component are typically reached BEFORE the maximum recommended dose of the epinephrine component. This may not be the case for more concentrated solutions which are normally reserved for local hemostasis, such as cartridges containing 1:50,000 epinephrine (i.e., the typical maximum recommended dose for adults treated with lidocaine 2% with epinephrine 1:100,000 is 11 cartridges; however, the typical maximum recommended dose for adults treated with lidocaine 2% with epinephrine 1:50,000 is 5.5 cartridges).
- For adults and children > 12 years old, 3 mcg (0.003 mg) of epinephrine/kg of body weight or 0.2 mg epinephrine per dental appointment is usually the maximum recommended dose.
Special Clinical Implications
Use with caution
- In patients taking non-selective beta-adrenergic blocking agents and who require simple restorative procedures, it is preferable to avoid epinephrine.
- For complex procedures that require a more prolonged duration of local anesthesia, keep initial vasoconstrictor doses to an absolute minimum (0.5 cartridge test dose) and inject carefully to avoid inadvertent intravascular injection.
- Frequently monitor (every 5 minutes) patient’s blood pressure and heart rate before giving additional doses, and an absolute maximum dose of 0.036 mg epinephrine (2 cartridges of a 1:100,000 solution) of epinephrine is advised, assuming the absence of a hypertensive response.
Pregnancy and lactation
- Use during pregnancy when the potential benefit to the mother outweighs the possible risk to the fetus.
- Excretion in breast milk unknown.
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