Many patients and dentists alike question the use of epinephrine in dental local anesthetics for pregnant women because of potential side effects. Those fears are not unfounded because another name for epinephrine is adrenaline. Yes, the same adrenaline that gets your heart racing if you had a fight or flight response such as being chased by a rabid dog.
According to the NIH’s PubChem database, epinephrine is indeed also known as adrenaline since it is produced in the adrenal gland. Therefore, that piece of information has been confirmed.
You may be wondering why there is adrenaline inside of your dentist’s local anesthetic but the answer may surprise you! Our purpose here today is to explain why epinephrine is not only safe to use but it actually makes it safer for expecting mothers. You shouldn’t shy away from getting it.
Is epinephrine safe to use in dental local anesthetics?
According to both The College of Obstetricians and Gynecologists (ACOG) and the American Dental Association (ADA), local anesthetics containing epinephrine are safe to use on pregnant patients. The guidelines specifically say that all necessary dental treatments should be completed and it may be done at any point in the pregnancy. This means that it doesn’t matter which trimester you are in.
In addition to that, it also states that local anesthetics including those with epinephrine are safe to use. Basically, there shouldn’t be any issue with your dentist’s anesthetic of choice. In case you didn’t know, there are only about five different local anesthetics that your dentist uses and they come with or without epinephrine.
Common dental local anesthetics:
- Lidocaine
- Mepivacaine
- Articaine
- Bupivacaine
- Prilocaine
You may have astutely noticed that Novocaine is not on there because it is actually no longer really used anymore. It has since been mostly replaced by Lidocaine a much newer drug. Articaine has also grown in popularity as well but it does cost more.
Why is epinephrine safe to use?
Dental local anesthetics with epinephrine are not only safe to use but they actually make it more safe when compared to using one without it. According to this study by the Journal of Dental Anesthesia and Pain Medicine, the adrenaline constricts the blood vessels at the site of injection.
What the constriction of the blood vessels does is to keep the anesthetic in the area longer. Consequently it keeps your tooth numb for a longer period of time. Another bonus effect is that it also prevents the anesthetic from entering the bloodstream where it can affect the fetus. Your body will have more time to metabolize the circulating amounts of anesthesia.
Basically it makes the overall procedure safer because you’ll be using LESS anesthesia over the course of treatment. There will also be SLOWER rate of absorption of the anesthesia into the bloodstream.
Therefore, using a local anesthetic with epinephrine is actually safer than using one without. That may be counterintuitive for most people to understand but it is the truth! The knee jerk reaction may be to avoid the adrenaline because we all know that it makes your heart start pumping faster but it has beneficial effects well beyond just that.
In case you were still not convinced, we can also dive into the pregnancy risk category of the local anesthetics.
Pregnancy risk categories of local anesthetic with epinephrine
The Food and Drug Administration (FDA) has a classification table in regards to drugs and their effects on pregnant patients called the pregnancy risk categories. It is categorized from A-D and X based on studies and their determined risks.
According to the study from the journal of dental anesthesia and pain medicine, most of the local anesthetics are rated as a “B” or “C”. In other words they can be used if the benefits outweigh the risks, especially for the category B which had no risk in animal studies. But just to reiterate, this applies to situations where procedures are not elective but rather needed such as for relieving pain.
| Local Anesthetic | Max Dosage (mg/kg) | Max Total Dosage | FDA Category |
| Lidocaine | 7 | 500 | B |
| Articaine | 7 | – | C |
| Mepivacaine | 7 | 550 | C |
| Prilocaine | 6 | 400 | B |
| Bupivacaine | – | 90 | C |
Overall the consensus is that it is fairly safe to use any of these anesthetics. What makes it even safer is that the maximum dosage ceiling is very high. The most commonly used drug is the Lidocaine and it has a max dosage of 500mg. According to the American Academy of General Dentistry (AGD) each carpule of lidocaine contains about 34-36mg. Typically for a dental procedure such as a filling, root canal, or extraction your dentist will use about 1-2 carpules on average. That means you’ll be receiving at most 78mg of the anesthetic out of the maximum of 500mg, which is well below the ceiling.
In other words, you shouldn’t be worried about overdosing with the anesthesia at all.
Takeaway
You don’t need to be worried about whether or not the anesthetic your dentist is using has epinephrine or not because they’re both safe to use. In fact, you should be asking them to choose one with it because it makes it even safer for the fetus. One with adrenaline will make the numbing last longer so you have to use less of it. It also makes it get absorbed into the bloodstream a lot slower as well, which is a double win in our opinion.
Last but not least, it also seems like the safest dental local anesthetic would be the Lidocaine since it is one of the two which holds a category B score for the pregnancy risk chart. Some of the other ones have a C rating, which is one tier below and probably slightly riskier.
Hopefully we’ve answered all of your questions in regards to whether or not it is safe to use adrenaline that is mixed in with the dental numbing shot while you’re pregnant. Now that you know, there should be no more hesitation in booking that needed dental appointment to have whatever dental condition that is bothering you.