Can Lidocaine Make You Jittery? Understanding the Cause

October 8, 2025 •

4 min read

A 2021 study found that about 2.2% of patients receiving a lidocaine and epinephrine injection for a minor procedure reported an 'adrenaline rush' with symptoms like nervousness and tremors. This low-risk but common side effect can make some people wonder, "Can lidocaine make you jittery?", and understanding the distinct causes is key to alleviating concern.

Quick Summary

Feeling jittery after a lidocaine injection can result from epinephrine, a vasoconstrictor often added to prolong the anesthetic effect. In rare cases, especially with high doses or rapid absorption, lidocaine itself can cause central nervous system stimulation or toxicity, leading to nervousness, tremors, and anxiety.

Key Points

Epinephrine is the primary culprit: In most cases, feeling jittery after a local anesthetic is caused by epinephrine, an additive that constricts blood vessels, not the lidocaine itself.
Adrenaline rush mimics: Epinephrine causes symptoms like a racing heart, nervousness, and shakiness, similar to a natural adrenaline rush.
Lidocaine toxicity is a rare cause: High plasma levels of lidocaine, typically from an accidental intravascular injection or overdose, can cause central nervous system excitation and lead to jitteriness.
Early warning signs of toxicity exist: Symptoms like a metallic taste, numbness around the mouth, tinnitus, or confusion can signal rising lidocaine levels.
Communicate with your doctor: Inform your healthcare provider of your symptoms and any pre-existing conditions to help distinguish between an epinephrine side effect and a potential toxicity issue.
Alternatives may be available: For patients sensitive to epinephrine, alternative local anesthetics without the vasoconstrictor may be an option.

The Dual Role of Lidocaine and Epinephrine

Lidocaine is a local anesthetic that works by temporarily blocking the sodium channels on nerve cells, preventing them from sending pain signals to the brain. However, the substance responsible for many cases of post-injection jitters is not lidocaine itself, but rather the epinephrine (also known as adrenaline) that is frequently combined with it.

Epinephrine is a vasoconstrictor, meaning it causes blood vessels to narrow. This addition serves two main purposes: to prolong the anesthetic effect by keeping the lidocaine localized to the injection site and to reduce bleeding during a procedure. While beneficial for the procedure, the epinephrine can cause systemic effects by stimulating the sympathetic nervous system. These effects, similar to a natural adrenaline rush, can include a rapid or pounding heart rate, flushing, anxiety, and tremors or shakiness. Because these symptoms are often unexpected and can feel intense, many patients mistakenly attribute them to an allergic reaction rather than a standard pharmacological effect of the epinephrine. Healthcare providers can help prevent patient anxiety by explaining this possibility beforehand.

How Lidocaine Itself Can Cause Jitteriness

While less common than epinephrine-induced jitters, lidocaine can cause nervousness and shaking on its own, particularly if it reaches toxic levels in the bloodstream. This can happen due to an excessive dosage, rapid absorption from a highly vascular area, or an accidental injection directly into a blood vessel.

Lidocaine toxicity affects the central nervous system (CNS) in a biphasic manner. Initially, at lower toxic concentrations, it causes CNS excitation by selectively blocking inhibitory neurons. This disinhibition can lead to symptoms like lightheadedness, nervousness, apprehension, and tremors. For some individuals, particularly those with pre-existing anxiety disorders, even therapeutic doses can trigger psychological symptoms like severe anxiety or fear.

If lidocaine levels continue to rise, the initial excitatory phase can progress to more serious CNS depression. This can manifest as drowsiness, slurred speech, confusion, and eventually lead to unconsciousness, seizures, and respiratory arrest. Early recognition of these warning signs is crucial for immediate medical intervention.

Factors Increasing the Risk of Lidocaine Toxicity

Several factors can influence the risk of developing systemic lidocaine toxicity, including:

Patient weight and body composition: Lower body mass can increase the risk of elevated plasma levels.
Liver function: Since lidocaine is metabolized by the liver, poor liver function can delay its clearance from the body.
Drug interactions: Co-administration with other medications, such as some antidepressants, can affect lidocaine's metabolism.
Injection site: Rapid systemic absorption is more likely when lidocaine is injected into highly vascular areas.

Epinephrine Side Effects vs. Lidocaine Toxicity: A Comparison


Feature	Epinephrine Side Effects	Lidocaine Toxicity (Initial Phase)
Cause	Release of epinephrine (adrenaline) into the bloodstream.	High plasma concentration of lidocaine.
Onset	Often immediate, within a few minutes of injection.	Can be delayed, depending on route and rate of absorption.
Severity	Generally mild and short-lived.	Potentially severe if levels continue to rise.
Key Symptoms	Racing or pounding heart, flushing, shakiness, general anxiety.	Lightheadedness, tinnitus (ringing ears), circumoral numbness (around the mouth), nervousness, confusion.
Progression	Symptoms typically resolve as epinephrine is metabolized.	Can escalate to seizures, respiratory depression, and unconsciousness.
Management	Reassurance, monitoring, and waiting for effects to subside.	Immediate medical intervention, including oxygen and supportive care.

How to Minimize Risk and What to Tell Your Doctor

Communication with your healthcare provider is the most effective way to minimize the risks of adverse reactions. Before receiving a local anesthetic, provide a complete medical history, including any previous reactions to local anesthetics, heart conditions, anxiety disorders, or medications you are taking. You can also ask if epinephrine is in the anesthetic solution and if a version without it is a suitable alternative for your procedure. If you experience any symptoms like nervousness, tremors, or a rapid heart rate, inform your provider immediately. While it may just be the epinephrine, it is important to rule out any signs of toxicity.

Conclusion

While the answer to "Can lidocaine make you jittery?" is yes, the root cause is often misunderstood. For the majority of people, post-injection jitters are a benign, temporary side effect caused by the epinephrine mixed with lidocaine, which mimics an adrenaline rush. However, in rare cases of systemic toxicity from high lidocaine levels, jitters can be an early warning sign of a more serious central nervous system reaction. Distinguishing between these two possibilities is critical, and open communication with your healthcare provider is the best way to ensure your safety and peace of mind during a procedure. If you experience unsettling symptoms, alerting your doctor immediately is always the recommended course of action.

Recognizing the Signs of Systemic Overexposure

It is important to be aware of the early warning signs of systemic toxicity to receive prompt medical attention. These symptoms can include:

Metallic taste in the mouth: One of the most classic early indicators of toxicity.
Numbness around the mouth (circumoral paresthesia): A tingling or numb sensation affecting the lips and surrounding skin.
Tinnitus (ringing in the ears): An auditory disturbance that can signal rising plasma levels.
Dizziness or lightheadedness: A common sign of early CNS effects.
Confusion or slurred speech: Indicates a higher level of CNS disruption.
Muscle twitching or tremors: One of the excitatory signs of CNS toxicity.
Anxiety or nervousness: Can be an initial psychological symptom before more severe effects occur.

Authority link

Mayo Clinic - Lidocaine (Injection Route) Side Effects

Frequently Asked Questions

Dentists and other healthcare providers use epinephrine with lidocaine primarily to prolong the anesthetic effect and reduce bleeding at the injection site. The vasoconstrictor keeps the anesthetic concentrated in the area for a longer-lasting numbing effect.

The feeling of jitters caused by epinephrine is usually short-lived, often subsiding within a few minutes to an hour after the injection as your body metabolizes the substance. The effect is typically mild and temporary.

Yes, in many cases, you can request an anesthetic solution without epinephrine. Your doctor or dentist will determine if this is a suitable option for your procedure, as the duration of the numbing effect will be shorter.

The initial signs of lidocaine toxicity typically involve the central nervous system and include a metallic taste in the mouth, numbness around the lips, tinnitus (ringing in the ears), and dizziness.

Allergic reactions to lidocaine itself are rare. Patients often mistake the systemic effects of epinephrine for an allergic reaction. True allergic reactions are managed conventionally.

Yes, a small minority of people are more sensitive to the effects of epinephrine, experiencing a more noticeable 'wired' or anxious feeling after injection. This can also be influenced by the patient's anxiety level surrounding the procedure.

If you experience symptoms that are severe, prolonged, or different from mild jitters, such as slurred speech, confusion, severe dizziness, or twitching, inform your healthcare provider immediately. These could be signs of systemic toxicity requiring intervention.