Local Anesthesia Toxicity – Signs & Symptoms and Management

Local Anesthesia is the most commonly used medication in dentistry to provide anesthesia or pain control for most dental procedures involving teeth, gums and supporting soft tissue. But like any medication there are chances of toxicity to local anesthetic if the correct dosage is not administered. It is always recommended to calculate the Dosage of Local Anesthetic Agent before administering it. Dose of Local Anesthesia: It is said to be the least amount of LA necessary to induce the intensity and required duration of pain control for the dental surgery being performed. It is important to be prepared for any Dental Emergency with a Dental Emergency Kit.

Factors to be considered to determine Dosage of Local Anesthetic and prevent LA Toxicity:

• Age of the patient
• Body Weight
• Liver Function
• Allergic Reaction to LA: How to Check if patient is Allergic to Local Anesthesia (Skin Test)
• Technique of LA administration: Inject the LA agent slowly into the tissue and avoid injection into Muscle or into any arteries or Veins (always aspirate before injecting)
• Type of LA Agent being used

Clinical Manifestations of Local Anesthesia Toxicity due to Overdose:

The Signs and Symptoms of LA toxicity defer depending on the severity of the overdose and the rapidity of it. It also depends on the duration of the excessive serum concentration of the LA agent. The Toxicity of LA overdose is divided into three types – Mild, Moderate and Severe

• Mild LA Toxicity: talkativeness, anxiety, slurred speech and confusion
• Moderate LA Toxicity: Tremors, dizziness, blurred vision, headache, stuttering, nystagmus, stuttering speech, drowsiness
• Severe LA Toxicity: Generalized Tonic Clonic seizures, cardiac dysrhthmia, cardiac depression leading to cardiac arrest

Management of Local Anesthesia Toxicity:

Local Anesthesia toxicity due to overdose should be treated by following the below mentioned steps, management depends on the severity of Toxicity. Immediate steps to be taken while suspecting LA toxicity is to stop administering LA and monitor the Vital signs of the patient.

In case of Mild Local Anesthetic Toxicity you need to monitor the vital signs, ask the patient to take deep breaths (Hyperventilate) with or without Oxygen administration depending on the patients condition and gain venous access in the meantime. Ask the patient to stay in Clinic for 1 hour to check for any symptoms.

In case of Moderate Toxicity you need to stop administering LA immediately, monitor Vital signs, Administer Oxygen and ask patient to take deep breaths or Hyperventilate, Position the patient in Supine position, observe the patient in clinic for 1 hour.

In case of Severe Toxicity stop administering LA immediately, in case of seizures protect patient from hurting themselves, Start IV, administer Diazepam (5mg to 25mg) or midazolam 2-6 mg slowly until the seizures are stopped, administer oxygen, constant monitoring of vital signs, call for medical assistance or be prepared to transfer to Emergency ward in hospital, Start Basic Life Support if necessary ad transfer to medical care facility.