Vasoconstrictor in anesthetic: what it is and why it matters
Quick facts
- Definition
- Substance added to local anesthetic that constricts the blood vessels at the injection site.
- Examples
- Epinephrine (adrenaline), the most used; felypressin, used with some dental anesthetics.
- What it is for
- Prolongs anesthesia, reduces bleeding and lowers absorption of the anesthetic into the circulation.
- Caution
- Uncompensated cardiovascular disease, uncontrolled hypertension, hyperthyroidism and some drug interactions.
- Relevance in HOF
- The blanching it causes can be mistaken for ischemia from vascular occlusion, or mask its first signs.
A vasoconstrictor is the substance added to local anesthetic to constrict the blood vessels at the injection site. The most used is epinephrine (adrenaline); in dentistry, felypressin is also used with some anesthetics. With the vessels constricted, the anesthetic takes longer to leave the site: anesthesia lasts longer, there is less bleeding and less anesthetic reaches the circulation. In HOF it also matters because of a visible effect: blanching of the skin.
What does the vasoconstrictor do and what calls for care?
| Point | With vasoconstrictor | Without vasoconstrictor |
|---|---|---|
| Duration of anesthesia | Longer | Shorter |
| Local bleeding | Less | More |
| Absorption into the circulation | Slower | Faster |
| Color of the infiltrated skin | May lighten temporarily | Generally no blanching |
| Possible systemic effects | Palpitations, anxiety, tremor, higher blood pressure | Related to the anesthetic itself |
Several hyaluronic acid fillers already come with lidocaine in the syringe, without a vasoconstrictor, to make the injection more comfortable. Dental cartridges, on the other hand, usually contain a vasoconstrictor. Knowing what is being used is part of the medical history and planning. The overview is in local anesthesia in HOF.
Who needs caution?
The choice of anesthetic and vasoconstrictor belongs to the licensed professional, based on the label and the patient's assessment. These call for special attention:
- Cardiovascular disease: unstable angina, recent heart attack, arrhythmias and uncontrolled hypertension.
- Uncontrolled hyperthyroidism.
- Interactions: some antidepressants, nonselective beta-blockers and use of stimulant drugs.
- Pregnancy: the choice of anesthetic follows a specific assessment.
How to tell vasoconstrictor blanching from ischemia?
This is the most important point for HOF. The skin blanching from a vasoconstrictor is usually confined to the infiltrated area and recedes as the effect wears off. Ischemia from vascular occlusion follows the territory of an artery, may come with disproportionate pain and progresses to lacy, mottled (livedo), bluish skin with slow capillary refill.
| Sign | Vasoconstrictor | Vascular occlusion |
|---|---|---|
| Area | Where the anesthetic was infiltrated | Territory of an artery, sometimes far from the injection point |
| Evolution | Recedes over time | Worsens, with livedo and color change |
| Pain | Generally absent, the area is anesthetized | May be severe, but the anesthesia can mask it |
Also called: local vasoconstrictor, adrenaline in anesthetic, anesthetic with epinephrine.
Frequently asked questions
What is the vasoconstrictor in anesthetic for?
It constricts the vessels at the site, which keeps the anesthetic where it was injected for longer. As a result, anesthesia lasts longer, there is less bleeding and less anesthetic reaches the circulation.
Does anesthetic with vasoconstrictor turn the skin white?
It can. The constriction of the vessels temporarily lightens the infiltrated area. This blanching is expected, but it must be told apart from the pallor of a vascular occlusion, which has a different pattern.