Doses - LIDOCAINE HCL

Dogs:

a) Initially, IV bolus of 2 - 4 mg/kg given slowly; then begin constant IV infusion of 25 - 80 micrograms/kg/min (Moses 1988)
b) 4 mg/kg bolus STAT, then begin 50 micrograms/kg/min constant infusion. If no effectrepeat 4 mg/kg bolus or if effect is lost give another 2 mg/kg bolus during infusionequilibration period. Adjust infusion rate from 25 - 100 micrograms/kg/min to controlarrhythmias and minimize toxicity.
Alternatively, give 6 mg/kg IM ever 1.5 hours; results may be more variable andmanagement more difficult. (Wilcke 1985)
c) 2 - 3 mg/kg slow IV, may repeat several times at 10-15 minute intervals; maximum of 8mg/kg over 10 minutes. Begin constant rate infusion (may be required for 1-3 days).(Tilley and Miller 1986)
Cats: Caution: Cats are reportedly very sensitive to the CNS effects of lidocaine, monitor carefullyand treat seizures with diazepam.
a) Initially, IV bolus of 0.25 - 0.75 mg/kg given slowly; then begin constant IV infusion of10 - 40 micrograms/kg/min (Moses 1988)
b) 0.5 mg/kg slow IV (Miller 1985)

Horses:

a) Initially IV bolus of 1 - 1.5 mg/kg. Will generally distinguish between ventriculartachyarrhythmias (effective) and supraventricular tachyarrhythmias (no effect). Tomaintain effect, a constant IV infusion will be required. (Hilwig 1987)
Monitoring Parameters -

1) ECG

2) Symptoms of toxicity (see Adverse Effects and Overdosage)

3) If available and indicated, serum levels may be monitored. Therapeutic levels are considered to range from 1 - 6 micrograms/ml.
Client Information - This drug should only be used by professionals familiar with its use and ina setting where adequate patient monitoring can be performed.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times -Lidocaine is approved for use in veterinary medicine (dogs, cats, horses, and cattle) as an injectable anesthetic, but it is not approved for use as an antiarrhythmic agent. Information regarding its use in food-producing species is conflicting. It is a prescription (Rx) drug.
Lidocaine HCl for Injection1% (10 mg/ml) in 5 ml (50mg) and 10 ml (100 mg) syringes2% (20 mg/ml) in 5 ml single use vials and syringes (preservative free)2% (20 mg/ml) in 100 ml multi-use vials; Veterinary (contains preservatives)
To prepare IV infusion solution using the veterinary 2% solution add 1 gram (50 ml of 2% solutionto 1 liter of D5W or other compatible solution, this will give an approximate concentration of 1mg/ml (1000 micrograms/ml). When using a mini-drip (60 drops/ml) IV set, each drop will containapproximately 17 micrograms. In small dogs and cats, a less concentrated solution may be used forgreater dosage accuracy. When preparing solution be certain that you are not using the lidocaineproduct that also contains epinephrine.
Lidocaine (human approved) is also available in 4%, 10%, and 20% preservative free solutions for IV admixture, for direct IM administration, and premixed with D5W for IV infusion in concentrations of 2 mg/ml, 4 mg/ml, and 5 mg/ml.Also known as lignocaine HCl. A common trade name is Xylocaine® (Astra).