Tetracaine
When ATH:
S01HA03
Characteristic.
Local anesthetics of ester groups. Tetracaine hydrochloride is a white crystalline powder, without smell. Easily soluble in water (1:10), alcohol (1:6), saline and dextrose, it is soluble in chloroform, practically insoluble in ether. rKa = 8,2. Molecular weight 300,83.
Pharmacological action.
Mestnoanesteziruyuschee.
Application.
Surface anesthesia for short-term operations and manipulations in ophthalmic (removal of the surface of foreign bodies, outpatient surgery, Gonioscopy, tonometry, other diagnostic procedures) and ENT practice; Suba in case of contraindications to the use of local anesthetics of the amide.
Contraindications.
Hypersensitivity (incl. to other local anesthetics group PABA esters or derivatives thereof and), injury or inflammation of mucous membranes, incl. epithelial damage or erosion of the cornea, childhood (to 10 years).
Pregnancy and breast-feeding.
Perhaps in exceptional cases, if the effect of therapy outweighs the potential risk to the fetus and newborn.
Category actions result in FDA - C. (The study of reproduction in animals has revealed adverse effects on the fetus, and adequate and well-controlled studies in pregnant women have not held, However, the potential benefits, associated with drugs in pregnant, may justify its use, in spite of the possible risk.)
Side effects.
Local Effects: irritation, contact type allergy, burning sensation, swelling and pain in the area of application; with long-term use in ophthalmology is keratitis, persistent corneal opacity, scarring of the cornea with a loss of visual acuity, slowing epithelialization.
Systemic side effects: cyanosis, CNS excitation, blurred vision, arrhythmia, anaphylactic shock.
Cooperation.
It reduces the antibacterial activity of sulfonamides. Vasoconstrictor prolong the effect and reduce toxicity. PM, inhibiting cholinesterase (antimiastenicheskie funds, cyclophosphamide, thiotepa et al.), reduce tetracaine metabolism and increase its toxicity. Antykoahulyantы (dalteparin sodium, enoxaparin sodium, Heparin sodium, warfarin) increase the risk of bleeding. When using tetracaine with PM, inhibit MAO (furazolidon, procarbazine, selegiline) It increases the risk of blood pressure lowering. Tetracaine strengthens and lengthens the effect of muscle relaxant drugs. Beta-blockers slow the metabolism of tetracaine, increasing its toxicity (reduction in hepatic blood flow).
Overdose.
Symptoms: dizziness, generalized weakness, excitation, anxiety, muscle tremors, convulsions, respiratory failure, collapse, metgemoglobinemiâ, nausea, vomiting, coma, OF блокада.
Treatment: Remove from the skin and mucous membranes; When oppression breath-IVL and oxygen therapy, When the collapse-in/with the introduction of blood products (saline, Gemodez, dextran preparations), the use of vasoconstrictors, cramps-diazepam or barbiturates short-acting (I /), When natal is 1-2 mg/kg metiltioniniâ chloride (Methylene blue) in/in or 100-200 mg of Ascorbic acid inside.
Dosing and Administration.
Dosage regimen individual. Locally, for surface anesthesia: generally used in ophthalmology 0,3% solution (≤2-3 drops); ambulatory surgical interventions carried out by instillation of additional need (1-2 Drops); for prolonged anesthesia — film. In otorhinolaryngology: in children older 10 years — no more than 1-2 ml 0.5-1% solution, in adults, until 3 ml 1% solution; the highest single dose for adults is 90 mg (3 ml 3% solution). For SUBA- 1% solution (cm. "Pharmacology").
Precautions.
In ophthalmology is not recommended for long-term or frequent (possible corneal damage). It will be appreciated, that solutions, containing more than 2% tetracaine, can cause damage to the corneal epithelium and a significant expansion of blood vessels of the conjunctiva.
To use caution in patients with reduced levels of plasma cholinesterase, heart rhythm disturbances, OF блокадой, shock. During the spinal anesthesia requires monitoring of blood pressure.
Cautions.
Tools and needles, contact with tetracaine, shall not contain residual alkali (forms an insoluble base).
