Ethyl Chloride (Monograph)

Drug class: Antipruritics and Local Anesthetics
ATC class: N01BX01
VA class: DE700
CAS number: 75-00-3

Medically reviewed by Drugs.com on Dec 23, 2024. Written by ASHP.

Introduction

Ethyl chloride (chloroethane) is a vapocoolant (skin refrigerant) local anesthetic.

Uses for Ethyl Chloride

Ethyl chloride is used as a local anesthetic in minor operative procedures such as incision of carbuncles or furuncles and removal of localized growths. The usefulness of ethyl chloride is limited in surgical procedures, however, because the anesthesia is of very short duration and thawing of frozen tissue is painful. In addition, freezing may injure cells, decrease resistance to infections, and delay healing.

Ethyl chloride is also used to alleviate pain associated with burns and insect stings and that of bruises, contusions, abrasions, swelling, and minor sprains associated with sports injuries. The drug has been used as an adjunct in the treatment of tinea lesions and creeping eruption.

As a counterirritant, ethyl chloride is used for the relief of myofascial and visceral pain syndromes.

Ethyl Chloride Dosage and Administration

Ethyl chloride is applied topically as a spray. The dosage of ethyl chloride varies with the procedure and the response of the patient. The smallest dose needed to produce the desired effect should be used. Ethyl chloride is commercially available in metal tubes with valve closures or in glass bottles with spring release closures. These containers have various size nozzle openings for regulation of spray. Usually, fine spray is used for local anesthesia. The container should be held in the hand prior to administration to increase the volatility of the liquid.

For use in local anesthesia, the container should be held about 3–9 inches from the area being treated and the spray directed downward to the target area for 3–7 seconds until the skin just begins to turn white but should not be frosted. Because the local anesthetic effect is very brief, incisions should be made promptly after swabbing with an antiseptic. To prevent pain of injection, the same ethyl chloride application technique should be followed; the needle for injection should then be introduced quickly with the skin taut after swabbing with an antiseptic.

When ethyl chloride is used as a counterirritant after the active irritated trigger point (a deep hypersensitive localized spot in a muscle) has been evaluated and identified, the container should be held about 12–18 inches from the skin and the pinpoint stream directed to meet the body at an acute angle to lessen the shock of impact. The spray should be applied in one direction only, starting at the trigger area and moving in parallel sweeps 1.5–2 cm apart slowly (10 cm/second) and evenly outward over the reference zone; sweeps should be repeated rhythmically until the area has been covered. The number of sweeps will depend on the size of the treated muscle. The skin should not be frosted because excessive cooling may increase muscle spasms and pain. With trigger points, the source of pain seldom is the site of pain. The affected muscle should be passively stretched during application, gradually increasing the force with successive sweeps. As the muscle relaxes, smoothly take up the slack by establishing a new stretch length. The full normal length of the muscle should be reached to completely inactivate the trigger point and relieve pain. The muscle should be rewarmed. Application may be repeated if necessary. Apply moist heat for 10–15 minutes after treatment. Eliminate factors that perpetuate the trigger mechanism.

Cautions for Ethyl Chloride

Because ethyl chloride is highly flammable, it should not be used in areas where ignition may occur.

Cutaneous sensitization to ethyl chloride may occur rarely. Freezing occasionally can alter pigmentation. The drug should not be applied to broken skin or mucous membranes. During application of ethyl chloride, the skin adjacent to the area being treated should be covered with petrolatum to protect against tissue sloughing. In addition, caution must be observed to avoid spilling the liquid on the skin. Although the manufacturer states that no case of chronic toxicity has been reported, ethyl chloride may be absorbed percutaneously and long-term exposure may result in nephrotoxicity and hepatotoxicity.

Inhalation of ethyl chloride vapor should be avoided when the drug is used for local anesthesia; deep general anesthesia followed by death has been reported. Patients who have been poisoned by inhalation of ethyl chloride vapors should be removed from the area of fumes and treated symptomatically. The patient should be observed for delayed nephrotoxicity or hepatotoxicity.

Pharmacology

The rapid vaporization of ethyl chloride when applied as a fine spray to the skin produces freezing of superficial tissues to -20°C, which results in insensitivity of peripheral nerve endings and local anesthesia (vapocoolant; skin refrigerant). Anesthesia is usually maintained for up to 1 minute.

Ethyl chloride also shares the pharmacologic actions of the hydrocarbon inhalation anesthetics.

Chemistry and Stability

Chemistry

Ethyl chloride (chloroethane) is a highly flammable, colorless liquid at low temperatures or under pressure. The very volatile liquid boils between 12–13°C; the vapor has a characteristic ethereal odor. Mixtures of ethyl chloride with 5–15% air are explosive. Ethyl chloride is slightly soluble in water and freely soluble in alcohol and in ether.

Stability

Ethyl chloride should be protected from light and stored in tight containers, preferably hermetically sealed, away from fire. Ethyl chloride should be stored in a cool place at controlled room temperature; it should not be stored on or near high-frequency ultra sonography equipment.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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