tetracaine: clinical use

Prescribing considerations

• Limit application to intact, normal skin and ensure the planned procedure does not risk middle-ear exposure.
• Use cautiously in epilepsy despite low systemic availability through intact skin.
• Repeated exposure may increase contact sensitisation; minimise contact and wash hands after handling.
• Parahydroxybenzoate preservatives may cause allergic reactions, including delayed reactions.

Contraindications and cautions

• Hypersensitivity to tetracaine, another ester-type local anaesthetic or a formulation excipient.
• Premature babies until one month after the expected delivery date, and full-term infants younger than one month.
• Application to broken skin, mucous membranes, eyes or ears.

Monitoring

• Inspect the site for excessive redness, oedema, itching or blistering.
• Remain alert to neurological toxicity if ingestion, excessive exposure or inappropriate application is suspected.

Clinical pharmacology

Tetracaine blocks voltage-dependent sodium conductance in peripheral nerves and is rapidly hydrolysed in blood, mainly by plasma pseudocholinesterase. Percutaneous systemic availability from intact skin is low but variable.

Formulation and product differences

• The selected product is a white, opalescent cutaneous gel supplied in single-use aluminium tubes.
• It contains sodium methyl and propyl parahydroxybenzoates, which can cause allergic reactions.
• It requires refrigerated storage, must not be frozen and should be protected from heat.