Lidocaine Hydrochloride

Description

Lidocaine HCI occurs as a white, odorless, slightly bitter-tasting, crystalline powder. It is soluble in water and alcohol. It is also known as lignocaine HCI.

Usage

Lidocaine HCI is a potent local anesthetic and anti-arrhythmic agent. It is compatible with most commonly used IV infusion solutions. Compatibility is dependent upon factors, such as pH, concentration, temperature, and dilutents used. It is considered to be a class IB (membrane-stabilizing) anti-dysrhythmic agent.

Besides its use as a local and topical anesthetic, lidocaine is used to treat ventricular arrhythmias.

Dosage and Administration

Other uses:

Dosage and administration per veterinarian's prescription for a particular horse and condition. General guidelines:

Epidural: 5-8 ml (Rose); 8-10 ml (IMS)

Ventricular tachycardia: Foals: 1-2 mg/kg followed by 20-50 mcg/kg/min IV (Robinson)

Acute cardiac ventricular tachycardia: 500 kg horse: 20 ml of 2% solution without epinephrine (H-D-M); 0.5-1 mg/kg IV as a bolus followed by calibrated IV drip. Try to achieve 1-6 mcg/ml serum levels. (H-D-M)

Postoperative ileus: IV bolus of 1.3 mg/kg followed by a IV infusion of 0.05 mg/kg/minute for 24 hours (Plumb) or until motility returns. (Kottenbelt)

Ileus: 1.3 mg/kg bolus over 5 minutes then 0.05 mg/kg/min for up to 24-72 hours (Rush, ACVIM 2006)

Side Effects

Toxic effects are usually related to central nervous system effects. Excitability, muscle tremors, and convulsions have been noted. Weakness and recumbency occur, but quickly disappear after discontinuation of the infusion.

Precautions

Caution should be used in horses with liver disease, congestive heart failure, shock, and respiratory depression.

Be sure not to use a product that contains epinephrine intravenously.

Lidocaine Hydrochloride is FDA-approved for use in horses. It is a prescription drug restricted to use by or on the lawful written or oral order of a licensed veterinarian.

The appropriate individual regulatory body should be consulted regarding use of Lidocaine HCI in competition horses.

Interactions

Licocaine effects may be increased by concomitant administration of cimetidine or propranolol. Other anti-arrhythmics administered with lidocaine may cause additive or antagonistic cardiac effects and toxicity may be enhanced. When given IV with phenytoin, increased cardiac depression may occur. Lidocaine may cause increased creatine kinase levels.

Overdose

Overdose symptoms include ataxia, depression, seizures, hypotension, and, at very high levels, circulatory collapse. Because lidocaine is rapidly metabolized, cessation of therapy or reduction of infusion rate may be all that is required to relieve minor symptoms. Seizures or excitement may be treated with diazepam or a short-acting barbiturate. Longer-acting barbiturates, such as pentobarbital should be avoided. If circulatory depression occurs, treat with fluids, pressor agents and, if necessary, begin CPR.