What Are the Side Effects of Lidocaine Anesthetic?

Lidocaine is an anesthetic medication that can be injected or used topically. Doctors use lidocaine to numb the skin and underlying tissues before simple surgical procedures or before the injection of another medication. Lidocaine inhibits the conduction of neuron impulses, according to Drugs.com, and prevents pain signals from going to the brain. Lidocaine works immediately and lasts about 60 to 90 minutes. Most patients tolerate lidocaine well; however, certain patient may experience significant side effects. A patient who may be exposed to lidocaine should be aware of these possible side effects.

Lidocaine being drawn from a bottle. (Image: ChaNaWiT/iStock/Getty Images)

Drowsiness

According to the Mayo Clinic, lidocaine may cause drowsiness. This occurs because lidocaine can travel through the bloodstream to the brain. In the brain, lidocaine may alter the conduction of neural impulses and cause a patient to become drowsy. Drugs.com warns that drowsiness may merge into unconsciousness and respiratory arrest. Therefore, a patient experiencing drowsiness should immediately let his doctor know. His doctor will then monitor the patient to make sure he does not lose consciousness or stop breathing.

Irregular Heartbeat

Drugs.com states that lidocaine may cause an irregular heartbeat. Specifically, lidocaine may cause the heart to slow down, which may lead to cardiac arrest. This occurs because lidocaine can travel in the bloodstream to the heart muscles and alter heart rate and contraction strength. This serious side effect requires prompt medical attention. If a patient begins to notice an uncharacteristic slowing of the heart, he should seek immediate medical treatment to prevent further cardiovascular complications.

Nervousness

Lidocaine may cause nervousness, states Drugs.com. In this case, lidocaine may cause nerve excitement, which will manifest as nervousness or anxiety in a patient. Nervousness is a serious side effect that also requires immediate medical treatment. A patient should not ignore of self-treat this side effect. Instead, he should call his doctor. His doctor may discontinue a lidocaine patch, or may keep the patient to closely monitor for other serious side effects.