Types of Local Anesthesia Used For Surgical Procedures

Local anesthesia is a type of pain prevention used during minor procedures to numb a small site where pain is likely to occur without changing the patient's awareness. You might be familiar with local anesthetics being used for dental procedures and numbing small areas that need to be stitched.

This article discusses how local anesthesia works, what drugs are used, and procedures it may be used for. It also covers what to expect if you will be getting local anesthesia and the risks that are involved.

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Why Local Anesthesia Is Used

Local anesthesia is typically used for minor procedures that can be completed in a short time and that allow the patient to return home the same day.

Unlike general anesthesia where the entire body is paralyzed and you are unconscious, local anesthesia allows you to remain awake and alert during a procedure. It only numbs a small area, whereas regional anesthesia numbs a whole arm, leg, or other region.

For this reason, local anesthesia is used for procedures in which pain prevention is necessary but the patient also needs control over their muscles. For example, it is useful for:

• Acute pain: Local anesthetics like lidocaine may be used to immediately relieve pain in patients with traumatic injuries or who have just had a stroke.
• Labor pain: An epidural is a type of local anesthetic that blocks nerve impulses in the lower spine without weakening the muscles needed to give birth.
• Postoperative pain: Local anesthetics may be used to prevent pain after a surgery and reduce the need for opioids.

Local anesthesia has many benefits over general anesthesia, but that doesn't mean one is better than the other.

How Local Anesthesia Is Given

Anesthesiologists are physicians who administer anesthesia and monitor their patients' breathing, circulation, heart rate, and other vital signs before, during, and after the procedure.

You will likely encounter an anesthesiologist for procedures that require a continuous IV infusion, like an epidural. The anesthesiologist will stay to monitor you throughout the procedure and check on you afterward.

For minor procedures in which vital signs do not need to be continuously monitored, like cavity fillings or mole removals, the dermatologist, dentist, or performing physician will administer the local anesthesia themselves.

Before they do, a numbing medication will be applied to the area in which the procedure will be performed. This numbing medication may be in the form of a cream, spray, or injection.

Numbing medications are sometimes given in several small injections. A few minutes after the injections have been given, the area should be completely numb. If the area still has sensation, additional injections may be given to ensure it is completely numb.

While the goal is to prevent pain, the injection itself can often be quite painful. That said, pain from the injection will be brief, and the shot will prevent you from feeling pain throughout the rest of the procedure.

Procedures Using Local Anesthesia

Local anesthesia is most commonly associated with minor procedures that may be painful but are not serious. Some examples of when local anesthesia is appropriate: 

• Dental procedures, such as filling a cavity or procedures where the gums must be numbed
• Suturing a wound
• Removing an ingrown toenail
• Placement of an IV in a child (to decrease pain in advance of insertion)
• Before a biopsy (to numb the skin so a sample can be collected)

Drugs Used for Local Anesthesia

Drugs used as local anesthetics suppress pain receptors known as nociceptors, blocking them from sending pain impulses to your brain.

Some of the most frequently used local anesthetic drugs are:

• Benzocaine
• Lidocaine
• Novocaine
• Tetracaine
  

Notice how each these ends in -caine. Local anesthetic drugs are related in structure to cocaine, which was used as an anesthetic between 1884 and 1914. But today's anesthetics differ from cocaine in that they are not addictive or habit-forming, and they don't raise blood pressure.

Which drug you may be given and at what dosage depends on whether you have any allergies, whether you or your family members have had previous reactions to anesthesia, other medications you are taking, and the length of the procedure, as well as your age, height, and weight.

How Long Local Anesthesia Lasts

How long the effects of the local anesthetic last depends on which drug was used and how much of the drug was given. Some drugs may take more time to kick in, but their effects last longer.

For example, the effects of lidocaine begin within two to five minutes after it is injected and last up to two hours. Another local anesthetic drug called bupivacaine takes five to 10 minutes to kick in, but its effects can last up to eight hours.

A synthetic form of the hormone epinephrine is sometimes combined with an anesthetic drug to prolong its effects. Combining lidocaine with epinephrine, for example, extends the effects of lidocaine from two to six hours.

Doctors typically begin by giving you the lowest dose of the drug necessary. If you are having a longer procedure, they may repeat the dose after a certain amount of time has passed to prolong the anesthesia.

Generally speaking, the effects of most local anesthetics begin to gradually wear off within a few hours after the procedure is complete.

For smaller procedures that involve local anesthesia, like mole removals or suturing a small wound, you will be able to go home as soon as the procedure is finished.

There are some cases when you will need to stay longer to have your status and vital signs monitored, for example, when a doctor applies local anesthetic inside your throat to examine your throat and vocal cords (laryngoscopy). Afterward, you will need to be monitored until your gag reflex returns to ensure it is safe for you to eat or drink.

Preparation for Local Anesthesia

Local anesthesia allows patients to feel a sense of being in control during their procedure. It takes much less time to recover from local anesthesia than it does with general anesthesia, and most procedures that use local anesthesia are relatively quick.

Nonetheless, you still need to take a few basic precautions before your procedure to prepare for the anesthesia. Your doctor should give you specific advice, which may include:

• Fasting from food or drink for a specified time before the procedure
• Avoiding alcohol or smoking at least 24 hours before the procedure
• Not wearing makeup if the procedure is being done on your face; removing jewelry from the surgical area

Doctors are very careful not to begin procedures until the anesthesia has kicked in. Your doctor should make it clear which drugs they are giving you, how long they will last, and anything else you should expect. They should also communicate with you throughout the procedure to make sure you are comfortable.

If you have any questions about your procedure or how you should prepare, don't hesitate to clarify them with your doctor.

Risks

The risk of side effects is significantly lower with local anesthesia compared to general anesthesia. Despite how safe local anesthetics usually are, it's possible for an individual to be unusually sensitive to a drug and develop severe side effects.

For this reason, there must always be emergency medical care available when local anesthetics are used. Serious but uncommon side effects that may occur during use include:

• Allergic reaction to the anesthetic drug
• Abnormal heart rhythm (arrhythmia)
• Seizure
  

Other serious but uncommon side effects that can arise in the days to weeks following a procedure involving local anesthesia include:

• Infection at the injection site
• Nerve or tissue damage at the injection site, which is usually temporary but can persist for a few months or permanently

The most common side effects following local anesthesia are soreness and bruising at the injection site. These side effects are also temporary and nothing to be concerned about. However, let your doctor know if a bruise expands or does not get better within a week or two.

You should also see your doctor if you develop the following side effects any time after your procedure:

• Signs of infection: Swelling, itching, pain, redness, pus drainage, or warmth at the injection site
• Signs of nerve or tissue damage: Numbness, weakness or loss of function, tingling, burning, or pain at the injection site

Summary

Local anesthesia is frequently used to minimize the pain a patient experiences during minor procedures. These procedures are typically quick and done on an outpatient basis, meaning the patient returns home the same day.

Drugs used as local anesthetics are very safe and effective. While the risk of side effects is low, there is always some level of risk with any drug. Make sure to ask your doctor what you should do to prepare and how much recovery time you should plan for.

A Word From Verywell

It's normal to feel anxious before a procedure, no matter how minor that procedure may be. Sometimes, anxiety comes from a lack of clarity about what to expect or why the procedure is even necessary.

If you are having any doubts, or if you find yourself wanting to cancel or delay your procedure, give your doctor a call and see if they can address your concerns.