What is local anesthesia?

Local anesthesia refers to using a drug called an anesthetic to temporarily numb a small area of your body. Your doctor might use a local anesthetic before doing a minor procedure, such as a skin biopsy. You might also receive local anesthesia before a dental procedure, such as a tooth extraction. Unlike general anesthesia, local anesthesia doesn’t make you fall asleep.

Local anesthetics work by preventing the nerves in the affected area from communicating sensations of pain to your brain. It’s sometimes used with a sedative. This helps you relax.

Keep reading to learn more about the different types of local anesthesia and when they’re used.

What are the different types?

There are two main types of local anesthetics, depending on how they’re administered.

Topical anesthetics

Topical anesthetics are applied directly to your skin or mucus membranes, such as the inside of your mouth, nose, or throat. They can also be applied to the surface of your eye. Topical anesthetics come in the form of:

  • liquids
  • creams
  • gels
  • sprays
  • patches

In some cases, your doctor might use a combination of local anesthetics for a more long-lasting effect.

Examples of procedures that might involve topical anesthesia include:

Over-the-counter (OTC) topical anesthetics, such as benzocaine (Orajel), can also help manage pain from:

Injection

Local anesthetics can also be given as an injection. Injectable anesthetics are typically used for numbing during procedures, rather than pain management.

Procedures that might include an injection of a local anesthetic include:

  • dental work, such as a root canal
  • skin biopsy
  • removal of a growth under your skin
  • mole or deep wart removal
  • pacemaker insertion
  • diagnostic tests, such as a lumbar puncture or bone marrow biopsy

Which type will I need?

The lists above are general examples. Several of these procedures, such as cataract surgery, can be done with either type of anesthetic. Your doctor will determine the best type for you based on several factors, including:

  • the length of the procedure
  • the size and location of the area that needs numbing
  • any underlying health conditions you have
  • any medications you take

How is it administered?

You don’t need to do much to prepare for local anesthesia. Just make sure to tell your doctor if you:

  • have any open wounds near the affected area
  • take any medications, especially ones that increase your risk of bleeding, such as aspirin
  • have a bleeding disorder

You’ll be given local anesthesia shortly before your procedure to give it time to start working. This usually only takes a few minutes. While you shouldn’t feel any pain, you might still feel sensations of pressure.

Tell your doctor right away if you start to feel any pain during the procedure. They may need to give you a higher dose.

Local anesthesia usually wears off within an hour, but you may feel some lingering numbness for a few hours. As it wears off, you might feel a tingling sensation or notice some twitching.

Try to be mindful of the affected area while the anesthesia wears off. It’s very easy to accidentally injure the numbed area in the few hours following a procedure.

For OTC local anesthetics like Orajel, be aware that it may sting or burn a little when you first apply it. Never use more than the recommended amount on the product’s label. It can be toxic if too much is absorbed in your skin.

What are the side effects?

Local anesthetics are generally safe and usually don’t cause any side effects, aside from some tingling as it wears off. However, if you’re given too much, or the injection goes into a vein instead of tissue, you might have more side effects, such as:

  • ringing in your ears
  • dizziness
  • numbness
  • twitching
  • a metallic taste in your mouth

In extremely rare cases involving very high doses, anesthesia may cause:

It’s also possible to have an allergic reaction to an anesthetic, but this is rare. A 2011 study estimates that only about 1 percent of people are allergic to local anesthetics. In addition, most allergic reactions to local anesthetics are due to a preservative in the anesthetic, rather than the drug itself.

Q:

Is local anesthesia safe for pregnant women?

A:

Yes, in certain instances, local anesthetics are safe for pregnant women. However, there are some considerations, including what type of anesthetic is used, how much is needed, and the stage of the pregnancy. Keep in mind that pregnancy does affect several organs, including the cardiovascular system, liver, and kidneys, and these may affect your body’s reaction to the anesthetic. Also, the anesthetic does go into the fetal circulation. This means it goes to the baby. During the first trimester, or 13 weeks of pregnancy, the baby’s organs and limbs are forming. It’s possible that the anesthetic could cause a birth defect. Considering this, it might be prudent to put off any elective procedure until after the pregnancy or later in the pregnancy. If you need a procedure with local anesthesia, talk to your doctor about the safety and any options for your unique situation.

Deborah Weatherspoon, PhD, RN, CRNAAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

The bottom line

Local anesthesia is a relatively safe way to numb a small area before a procedure. It can also help manage pain on your skin or in your mouth. While it can occasionally cause side effects, this usually only happens in cases that involve doses above the recommended amount.