Cetacaine Anesthetic

Uses

This is a topical anesthetic used for the production of anesthesia of all accessible mucous membrane except the eyes. This reparation is used to control pain and for use for surgical or endoscopic or other procedures in the ear, nose, mouth, pharynx, larynx, trachea, bronchi and esophagus. It may also be used for vaginal or rectal procedures when feasible.
Pediatric Use: Safety and effectiveness of this gel in pediatric patients have not been established.

Cetacaine Anesthetic is also used to associated treatment for these conditions: Acute Sore Throat Pain, Dental Pain, Gangrene Stomatitis, Gingivitis, Hemorrhoids, Laryngitis, Pharyngitis, Premature Ejaculation, Secondary Bacterial Infection caused by Tonsillectomy, Secondary Bacterial Infection caused by Tooth Extractions, Skin Irritation, Sore Throat, Stomatitis, Sunburn, Teething pain, Tonsillitis, Tooth Pain, Vomiting, Pruritic dermatosis, Ulceration of the mouth, Buccopharyngeal anesthesiaDermabrasion, Hemorrhoids, Insect Bites, Rash caused by poison ivy, Sunburn, Minor burns, Anesthetics, Local, Local Anesthesia of the Skin, Local anesthesia therapy

How Cetacaine Anesthetic works

Benzocaine diffuses into nerve cells where it binds to sodium channels, preventing the channels from opening, and blocking the influx of sodium ions. Nerve cells unable to allow sodium into cells cannot depolarize and conduct nerve impulses.

Butamben acts by inhibiting the voltage-gated calcium channels in dorsal root ganglion neurons. The modification in this channels is thought to cause a disturbance of the channel kinetics acceleration. It is reported as well that butamben is an inhibitor of the sodium channels and a delayed rectifier of potassium currents. All the effects of butamben are performed in the root ganglion neurons which suggests that the related anesthetic effect may be caused by the reduced electrical excitability.

Tetracaine is an ester-type anesthetic and produces local anesthesia by blocking the sodium ion channels involved in initiation and conduction of neuronal impulses.

Dosage

Cetacaine Anesthetic dosage

Dispense and apply 200 mg of gel (a bead approximately 1/4 to 1/2 inches long) by gently squeezing the tube. Application of gel in excess of 400 mg is contraindicated. Spread thinly and evenly over the desired area using a cotton swab. An appropriate pediatric dosage has not been established for this topical gel. Dosages should be reduced in the debilitated elderly, acutely ill, and very young patients Tissue need not be dried prior to application of this topical gel. It should be applied directly to the site where pain control is required. Anesthesia is produced within one minute with an approximate duration of thirty minutes. Each 200 mg dose of this topical gel contains 28 mg of benzocaine, 4 mg of butamben and 4 mg of tetracaine HCl.

Side Effects

Hypersensitivity Reactions: Unpredictable adverse reactions (i.e. hypersensitivity, including anaphylaxis) are extremely rare. Localized allergic reactions may occur after prolonged or repeated use of any aminobenzoate anesthetic. The most common adverse reaction caused by local anesthetics is contact dermatitis characterized by erythema and pruritus that may progress to vesiculation and oozing. This occurs most commonly in patients following prolonged self-medication, which is contraindicated. If rash, urticaria, edema, or other manifestations of allergy develop during use, the drug should be discontinued. To minimize the possibility of a serious allergic reaction, this topical gel preparations should not be applied for prolonged periods except under continual supervision. Dehydration of the epithelium or an escharotic effect may also result from prolonged contact.

Toxicity

Patients experiencing an overdose may present with local anesthetic systemic toxicity syndrome, decreased cardiovascular function, decreased central nervous system function, cardiac arrest, bradycardia, hypotension, cardiac arrhythmias, syncope, and seizures. Patients should be treated with symptomatic and supportive measures which include airway maintenance, controlling seizures, and hemodynamic stabilization.

In studies, the most common effect was related to the generation of a prolonged effect. It was also shown in preclinical trials to produce tissue necrosis and neuritis. The LD50 of butamben is registered to be of 67 mg/kg.

The most common adverse effects with the combination cream are localized reactions such as: erythema (47%), skin discoloration (16%), and edema (14%). Systemic adverse events were less common, occurring at a rate of <1% and included vomiting, headache, dizziness, and fever. Similar to other amide and ester anesthetics, CNS excitation and/or depression may occur. It is not well known at which plasma concentration systemic toxicity occurs with tetracaine; however, the threshold is thought to be much lower than that of lidocaine which is 1000 ng/mL.

Precaution

On rare occasions, methemoglobinemia has been reported in connection with the use of benzocaine-containing products. Care should be used not to exceed the maximum recommended dosage (see Dosage and Administration). If a patient becomes cyanotic, treat appropriately to counteract (such as with methylene blue, if medically indicated).

Interaction

May antagonise the therapeutic effect of sulfonamides. Anticholinesterases may inhibit the metabolism benzocaine.

Volume of Distribution

This pharmacokinetic property has not been determined.

Tetracaine is rapidly hydrolyzed in the plasma; therefore, volume of distribution could not be determined.

Elimination Route

When butamben is administered epidurally in a suspension form, the physical characteristics of butamben allow a very slow release. When administered topically, butamben is also reported to have a very low systemic absorption which allows for a longer duration of action.

Systemic absorption of anaesthetic from the combination cream is directly related to the duration and surface area of application. Although peak plasma concentrations for lidocaine were measured, plasma levels for tetracaine could not be determined due to low levels (<0.9 ng/mL)

Half Life

The effective half-life of unencapsulated butamben is registered to be of 90 minutes. Some efforts were made to prepare D, L-lactic acid capsules which increased the half-life of butamben to even 400 hours.

Tetracaine is hydrolyzed rapidly in the plasma; therefore, half-life has not been determined.

Clearance

Clearance is flow-limited and it highly depends on the state of protein-bound form.

Tetracaine is hydrolyzed rapidly in the plasma; therefore, clearance has not been determined.

Elimination Route

The metabolites found in plasma after cholinesterase processing are disposed of in the urine.

Pregnancy & Breastfeeding use

Safe use of this gel has not been established with respect to possible adverse effects upon fetal development. Therefore, this gel should not be used during early pregnancy, unless in the judgement of a physician, the potential benefits outweigh the unknown hazards. Routine precaution for the use of any topical anesthetic should be observed when this gel is used.

Contraindication

This topical gel is not suitable and should never be used for injection. Do not use on the eyes. To avoid excessive systemic absorption, this topical gel should not be applied to large areas of denuded or inflamed tissue. This topical gel should not be administered to patients who are hypersensitive to any of its ingredients or to patients known to have cholinesterase deficiencies. Tolerance may vary with the status of the patient. This topical gel should not be used under dentures or cotton rolls, as retention of the active ingredients under a denture or cotton roll could possibly cause an escharotic effect. Routine precaution for the use of any topical anesthetic should be observed when using this topical gel.

Acute Overdose

Symptom: Methaemoglobinaemia, manifested by cyanotic (greyish) skin discolouration, unusual breathing or breathlessness.

Management: Symptomatic and supportive treatment. IV methylene blue 1% may be administered.

Storage Condition

Store in a cool and dry place, protect from light. Keep out of reach of children.

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