Cetacaine
Cetacaine (benzocaine + tetracaine + butamben)
Combination topical ester local anesthetic spray
Benzocaine/tetracaine/butamben ester blend for rapid topical mucosal anesthesia.
Indications
- •Topical anesthesia for airway instrumentation, endoscopy, awake intubation adjunct
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Topical spray | ≤1 second spray — dose is hard to titrate; methemoglobinemia risk | — |
Pharmacokinetics
Onset ~30 sec, duration ~30–60 min.
Side effects
- !METHEMOGLOBINEMIA (benzocaine + tetracaine both contribute)
- !Ester allergy
Contraindications
- ×Methemoglobinemia risk
- ×Ester allergy
Clinical pearls
- ★Two methemoglobinemia-causing esters in one spray — brief application only; have methylene blue available.
Other drugs in Local Anesthetics
- Lidocaine
Blocks voltage-gated Na⁺ channels in nerves (LA) and cardiac myocytes (antiarrhythmic).
- Bupivacaine
Voltage-gated Na⁺ channel blocker. Higher protein binding and lipid solubility than lidocaine → longer duration but greater cardiotoxicity.
- Ropivacaine
S-enantiomer of propivacaine. Less lipid-soluble than bupivacaine → less cardiotoxicity but slightly less potency.
- Tetracaine
Blocks voltage-gated Na⁺ channels. Long-acting ester, metabolized by plasma cholinesterase. High potency + toxicity.
- Chloroprocaine
Na⁺-channel blocker. Extremely rapid plasma-cholinesterase metabolism (half-life seconds) → lowest systemic toxicity of the LAs, ideal for OB epidural top-up.
- Procaine
Na⁺-channel blocker; prototype ester LA. Plasma-cholinesterase metabolized to PABA.
- Prilocaine
Na⁺-channel blocker. Metabolized to o-toluidine → oxidizes hemoglobin → methemoglobinemia at high doses.
Suggested reading
- •Stoelting & Hines, Pharmacology & Physiology in Anesthetic Practice, 6e
- •FDA package insert
- •ASRA LAST checklist, 2020
