Contraindications for Tetracaine
Tetracaine is contraindicated in patients with hypersensitivity to tetracaine or other ester-type local anesthetics, in patients with severe liver failure, and should not be used on broken skin or mucous membranes due to risk of systemic absorption.
Absolute Contraindications
- Hypersensitivity/allergy to tetracaine or other ester-type local anesthetics 1
- Broken or damaged skin (due to increased risk of systemic absorption)
- Severe liver failure (decreased clearance of local anesthetics) 1
- Use in children under 8 years of age (risk of teeth staining) 2
Relative Contraindications and Cautions
Medical Conditions
- Methemoglobinemia risk: Tetracaine, like other ester anesthetics, can cause methemoglobinemia 1
- Cardiovascular disease: Local anesthetics can have cardiac depressant effects 1
- Severe systemic disease: Higher risk of adverse effects
- Sepsis: Increased risk of systemic absorption and toxicity
Medication Interactions
- Monoamine oxidase inhibitors: Contraindicated for use in combination 1
- Concomitant use with other local anesthetics: Increased risk of toxicity due to additive effects 1
Application Sites
- Conjunctival use: Higher toxicity compared to other ocular anesthetics like proparacaine 3
- Large surface areas: Risk of systemic absorption and toxicity 1
- Mucous membranes: Increased absorption and risk of toxicity 4
Special Populations
Pediatric Patients
- Use with caution in pediatric patients
- Risk of respiratory distress and seizures has been reported 4
- Careful dosing is essential to prevent toxicity
Pregnant and Lactating Women
- Limited data on safety during pregnancy
- Use only when benefits clearly outweigh risks
Signs of Toxicity to Monitor
- Central nervous system: Seizures, respiratory depression
- Cardiovascular system: Hypotension, arrhythmias, cardiac arrest
- Methemoglobinemia: Cyanosis despite adequate oxygen delivery 1
- Treatment: Intravenous methylene blue 1-2 mg/kg over 3-5 minutes
Practical Considerations
- Maximum recommended dose without epinephrine is 1 mg/kg 1
- Duration of action ranges from 180-600 minutes 1
- When used topically, tetracaine has shown higher cytotoxicity compared to proparacaine and cocaine in corneal epithelial cells 3
Risk Mitigation
- Calculate maximum allowable safe dosage (mg/kg) before administration
- Avoid prolonged or repeated application
- Have resuscitation equipment readily available
- Monitor vital signs during and after administration in high-risk patients
- Consider alternative agents (like lidocaine) in patients with risk factors
By understanding these contraindications and taking appropriate precautions, clinicians can minimize the risks associated with tetracaine administration while still benefiting from its effective local anesthetic properties.