TETRACAINE HYDROCHLORIDE

TETRACAINE HYDROCHLORIDE (tet'ra-kane) Pontocaine Classifications: local anesthetic (ester type); Therapautic: local anesthetic Prototype: Procaine HCl Pregnancy Category: C

Availability

1%, 0.2%, 0.3% injection; 20 mg powder; 2% solution; 1%, 2% cream; 2% gel; 1% ointment; 0.5% ophthalmic solution

Action

A potent and toxic local anesthetic that depresses the initial depolarization phase of the action potential, thus preventing propagation and conduction of the nerve impulse.

Therapeutic Effect

Effectiveness indicated by loss of sensation and motor activity in circumscribed body areas close to injection or application site.

Uses

Spinal anesthesia (high, low, saddle block) and topically to produce surface anesthesia. Eye: To anesthetize conjunctiva and cornea prior to superficial procedures (including tonometry, gonioscopy, removal of foreign bodies or sutures, corneal scraping). Nose and Throat: To abolish laryngeal and esophageal reflexes prior to bronchoscopy, esophagoscopy. Skin: To relieve pruritus, pain, burning.

Contraindications

Older adult and debilitated patients; prolonged use of ophthalmic preparations; known hypersensitivity to tetracaine or other local anesthetics of ester type (e.g., procaine, chloroprocaine, cocaine), sulfite, or to PABA or its derivatives; coagulopathy; anticoagulant therapy; thrombocytopenia; increased bleeding time; infection at application or injection site; pregnancy (category C).

Cautious Use

Shock; cachexia, cardiac decompensation; QT prolongation; lactation; elderly; children <16 y.

Route & Dosage

Local Anesthesia Adult: Topical Before procedure, 1–2 drops of 0.5% solution or 1.25–2.5 cm of ointment in lower conjunctival fornix or 0.5% solution or ointment to nose or throat Spinal 1% solution diluted with equal volume of 10% dextrose injected in subarachnoid space

Administration

Topical

• Avoid use of solutions that are cloudy, discolored, or crystallized.
• When tetracaine is used on mucosa of larynx, trachea, or esophagus, the manufacturer recommends adding 0.06 mL of a 0.1% epinephrine solution to each mL tetracaine solution to slow absorption of the anesthetic.
• Store ophthalmic solution and ointment at 15°–30° C (59°–86° F); refrigerate topical. Avoid freezing. Use tight, light-resistant containers.

Adverse Effects (≥1%)

Body as a Whole: Anaphylactic reactions, convulsions, faintness, syncope. CNS: Postspinal headache, headache, spinal nerve paralysis, anxiety, nervousness, seizures. CV: Bradycardia, arrhythmias, hypotension. Special Senses: Stinging; corneal erosion, retardation or prevention of healing of corneal abrasion, transient pitting and sloughing of corneal surface, dry corneal epithelium; dry mucous membranes, prolonged depression of cough reflex.

Interactions

Drug: May antagonize effects of sulfonamides.

Pharmacokinetics

Onset: 1 min eye; 3 min mucosal surface; 3 min spinal. Duration: Up to 15 min eye; 30–60 min mucosal surface; 1.5–3 h spinal. Metabolism: In liver and plasma. Elimination: In urine.

Nursing Implications

Assessment & Drug Effects

• Recovery from anesthesia to the pharyngeal area is complete when patient has feeling in the hard and soft palates and when muscles in the faucial (tonsillar) pillars contract with stimulation.
• Do not give food or liquids until these normal pharyngeal responses are present (usually about 1 h after anesthetic administration). The first small amount of liquid (water) should be given under supervision of care provider.
• Be aware that increased blood concentration of the drug may result from excess application of tetracaine to the skin (to relieve pruritus or burning), application to debrided or infected skin surfaces, or too rapid injection rate.
• High blood concentrations of tetracaine can lead to adverse systemic effects involving CNS and CV systems: Convulsions, respiratory arrest, dysrhythmias, cardiac arrest.

Patient & Family Education

• Do not use ophthalmic drug longer than prescribed period. Prolonged use to eye surface may cause corneal epithelial erosions and retard healing of corneal surface.
• Natural barriers to eye infection and injury are removed by the anesthesia. Do not rub eye after drug instillation until anesthetic effect has dissipated (evidenced by return of blink reflex). Patching for temporary protection of the corneal epithelium may be ordered.
• Wash or disinfect hands before and after self-administration of solutions or ointment.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug