Is a single 60 mg intravenous dose of lidocaine (not given as an infusion) likely to cause acute hearing loss or tinnitus?

A Single 60mg IV Dose of Lidocaine is Unlikely to Cause Acute Hearing Loss or Tinnitus

A single 60mg intravenous dose of lidocaine is unlikely to cause acute hearing loss or tinnitus; in fact, this dose is commonly used therapeutically to treat tinnitus, and the evidence shows it is generally safe with only transient, mild side effects at this dosage level.

Understanding the Dose and Context

The 60mg dose you're asking about is:

• Well below toxic thresholds: The international consensus guidelines recommend loading doses up to 1.5 mg/kg over 10 minutes (which would be ~105mg for a 70kg patient) 1
• Within therapeutic range: Doses of 60mg are specifically used in clinical studies to treat tinnitus, not cause it 2, 3
• Associated with plasma levels <5 μg/ml: This is below the concentration where serious toxicity typically begins 1

What the Evidence Shows About Tinnitus and Lidocaine

Lidocaine as Treatment, Not Cause

Multiple studies demonstrate that 60mg IV lidocaine is used therapeutically for tinnitus:

• In a study of 155 cases, 60mg in men (40mg in women) was administered five times with a 60.2% effective rate for reducing tinnitus 2
• Another study using 60mg or 100mg doses showed 70.9% of patients experienced complete or partial tinnitus relief within 5 minutes 3
• The FDA label lists tinnitus as a symptom of CNS toxicity, but this occurs at high plasma levels from excessive dosage or rapid administration 4

The Toxicity Spectrum

According to the consensus guidelines, tinnitus appears on the toxicity spectrum diagram at plasma concentrations well above what a single 60mg dose would produce 1. The progression is:

1. Low levels: Tingling tongue/lips, light-headedness
2. Moderate levels: Tinnitus, slurred speech
3. High levels: Muscle twitching, loss of consciousness
4. Toxic levels: Respiratory arrest, cardiac effects

Hearing Threshold Effects

One study specifically examined hearing thresholds after IV lidocaine in normal subjects 5:

• Both increases and decreases in thresholds were observed
• Changes were frequency-specific (higher frequencies more affected)
• The study suggests lidocaine may act on inner ear hair cells
• However, these were temporary threshold shifts, not permanent hearing loss

Expected Side Effects at 60mg

At this dose, if any side effects occur, they would typically be 4, 2:

• Transient and mild: Light-headedness, dizziness, facial flushing
• Brief duration: Effects resolve as plasma levels decline
• Not severe: The study using 60mg reported "none of the side effects experienced were severe, and all were transient" 2

Clinical Caveats

When Tinnitus Might Occur

Tinnitus from lidocaine toxicity requires:

• Rapid bolus administration (the guidelines specifically warn against this) 1
• Inadvertent intravascular injection at high concentrations 4
• Accumulation from repeated dosing without appropriate intervals 4
• Patient-specific factors: Hepatic disease, elderly/debilitated patients, or those with impaired metabolism 4

The Paradox

Interestingly, one study found that 30% of patients reported increased tinnitus after lidocaine, but this was in a controlled trial context and may reflect the heterogeneous nature of tinnitus itself 6. The therapeutic window shows most relief occurs at plasma concentrations between 1.5-2.5 μg/ml 7.

Bottom Line for Your Patient

For a patient who received only 60mg IV lidocaine as a single dose (not an infusion):

• This is a standard therapeutic dose used to treat tinnitus
• Acute hearing loss is not an expected outcome
• If tinnitus or hearing changes occurred, consider alternative explanations first
• Any lidocaine-related effects at this dose would be transient (minutes to hours, not permanent)
• The dose is well within safety margins established by international guidelines 1

If your patient is experiencing hearing loss or tinnitus after this dose, investigate other concurrent factors: the underlying condition being treated, other medications, hemodynamic changes, or pre-existing auditory pathology rather than attributing it to the lidocaine dose itself.