What is the formulation and concentration of TAC (tetracaine) 0.1%?

Formulation of TAC 0.1%

TAC 0.1% refers to a topical anesthetic formulation containing tetracaine 0.1% concentration, typically combined with other agents such as epinephrine and cocaine in a solution form.

Composition and Formulations

• TAC traditionally stands for Tetracaine, Adrenaline (Epinephrine), and Cocaine, which was originally formulated as a topical anesthetic for use in emergency departments, particularly for pediatric facial and scalp lacerations 1
• The classic TAC formulation has evolved over time, with various concentrations being used in clinical practice:
  • Traditional "full-strength" TAC contained high concentrations of tetracaine, epinephrine, and cocaine 1
  • "Half-strength" formulations were later developed to reduce toxicity risks while maintaining efficacy 1
• The 0.1% concentration refers specifically to the tetracaine component of the formulation 1

Clinical Applications

• TAC is primarily used as a topical anesthetic for:
  • Pediatric facial and scalp lacerations in emergency departments 1
  • Some procedures requiring topical anesthesia of mucous membranes 1
• Tetracaine is also used in other formulations:
  • In ophthalmology as a topical anesthetic (typically 0.5-1% concentration) 2, 3
  • In nasal procedures, where tetracaine 0.5-2% with oxymetazoline 0.05% has shown superior anesthetic properties compared to other combinations 4
  • In bronchoscopy procedures as a topical anesthetic (0.45% solution) 5

Safety Considerations

• TAC formulations must be used with caution due to potential toxicity:
  • Application to mucous membranes has caused serious adverse events including seizures and deaths 1
  • Should not be applied to lacerations involving the vermillion border of the lip 1
  • Maximum recommended dose of tetracaine for topical anesthesia is traditionally 20 mg, though higher doses have been used in controlled settings 5
• When used appropriately for dermal applications, tetracaine has demonstrated a favorable safety profile:
  • Studies have shown tetracaine to be safe for 24-hour use in corneal abrasions 3
  • Tetracaine has a more rapid onset of action compared to some other topical anesthetics 2

Administration Methods

• TAC is typically administered via:
  • Soaked gauze or cotton ball applied directly to the wound 1
  • Spray formulations for nasal procedures 4
  • Drops for ophthalmic use 2, 3
• The solution should be carefully applied by medical personnel to avoid contact with mucous membranes 1

Pharmacological Properties

• Tetracaine is an ester-type local anesthetic that provides:
  • Rapid onset of action (as quick as 30 seconds in some applications) 2
  • Longer duration of action compared to some other topical anesthetics 4, 2
  • More potent anesthetic effect than lidocaine 4
• The 0.1% concentration represents a balance between efficacy and safety for specific applications 1