Duration of Action of Local Anesthetic Agents

Given under are the Duration of action of Local Anesthetic agents in Dental Practice. The uses of different local anesthetic agents in different situations is based on the duration of local anesthesia. Long acting Anesthetic agents are used in surgical procedures which are time taking and short or medium acting agents are used in procedures which are of shorter duration. Surgical procedures such as Dental Impactions, Multiple Dental Implant placements, Cyst Eneculation, etc require longer duration of Anesthesia.

Shorter acting local anesthesia is preferred in young, old or Mentally disabled patients who are at risk of traumatic injury due to prolonged anesthesia. In such patients shorter acting local anesthesia is preferred. Let us look at the various Local Anesthesia agents and their respective Duration of Action.

Duration of action of various Local anesthetic agents used in dental practice:

Etidocaine – 200 min

Bupivacaine Hydrochloride 0.5% with Epinephrine 1:200000 – 175 min

Tetracaine – 175 min

Lignocaine / Lidocaine- 175 min (Commonly used for Tooth Extraction and also as a Topical Local Anesthetic agent)

• Without Vasoconstrictor – 10 mins (Pulpal Anesthesia) and 30-45 mins (Soft Tissue)
• With Epinephrine 1:50,000 – 60 mins (Pulpal) and 180 to 300 mins (Soft Tissue)
• With Epinephrine 1:100000 – 60 mins (Pulpal) and 180 to 300 mins (Soft Tissue)

Mepivacaine Hydrochloride – 

• 3% without Vasoconstrictor – 5-10 mins (Pulpal) and 90 to 120 mins (Soft Tissue)
• 2% with Levonordefrin 1:20000 – 60 mins (Pulpal) and 180 – 300 mins (Soft Tissue)

Atricaine 4% with Epinephrine 1:200000 – 45-60 mins (Pulpal Anesthesia) and 180 to 240 mins (Soft Tissue Anesthesia)

Prilocaine – 50 min (Used in children because of the short duration of action, which prevents self inflicting injuries to the lip under anesthesia)

• 4% without vasoconstrictor – 40 to 60 mins (Pulpal) and 120 – 240 mins (Soft Tissue)
• 4% with Epinephrine 1:200000 – 60 to 90 mins (Pulpal) and 180 to 480 mins (Soft Tissue)

As you can see that Lignocaine is the widely used Local anesthetic agent for Tooth Extraction or any minor Surgical procedure, the

Duration of Action of Local anesthesia after a Dental or Tooth extraction – 3 hrs after the LA injection was given

So there is no need to worry about the numbness and lack of sensation after a tooth extraction which is not reduced even after returning home from the clinic, but you have to visit your dentist if the Numbness and Lack of sensation are not reduced even after 4-5 hrs of LA injection.

In some cases where Prolonged Effect of Local Anesthesia is not required there is an Agent called Phentolamine Mesylate which helps in reversing the Effect of local anesthesia. This is very useful in Younger or Elder patients or Mentally Disabled who are more prone to Trauma due to Lip or Tongue biting on prolonged unnecessary Anesthesia.

To know more about Local Anesthetic agents visit – Local Anesthetic agents Composition, Classification, Ideal Properties and Complication