
EVERY EFFORT SHOULD BE MADE TO AVOID POSSIBLE INADVERTENT INTRAVASCULAR ADMINISTRATION THROUGH APPROPRIATE SELECTION OF INJECTION SITE SUCH AS THIGH OR DELTOID. DO NOT INJECT INTO BUTTOCK. Monitoring with an electrocardiograph is recommended when lidocaine hydrochloride is administered by the intramuscular route. In emergency situations when a ventricular rhythm disorder is suspected and electrocardiographic equipment is not available, a single dose may be administered when the physician in attendance has determined that the potential benefits outweigh the possible risks. If possible, emergency resuscitative equipment and drugs should be immediately available to manage potential adverse reactions involving the cardiovascular, respiratory, or central nervous system.
Occasional acceleration of ventricular rate may occur when lidocaine hydrochloride is administered to patients with atrial fibrillation.
There is currently no manufacturer warning information available for this drug.
Lidocaine hydrochloride is indicated in the management of cardiac arrhythmias, particularly those of ventricular origin, such as occur with acute myocardial infarction.
The selection of the intramuscular route of administration (single dose) is justified in the following circumstances:
Lidocaine hydrochloride: acetamide, 2-(diethylamino)-N-(2, 6-dimethylphenyl)-, monohydrochloride has the following structural formula:

Lidocaine Hydrochloride Injection, intramuscular for Cardiac Arrhythmias, is a non-pyrogenic, sterile solution prepared from lidocaine hydrochloride, USP and Water for Injection. Lidocaine hydrochloride: C14H22N2O • HCI • H2O has a molecular weight of 288.82.
Each LidoPen® contains 300 mg lidocaine hydrochloride, 3 mg disodium edetate, 3 mg methylparaben, sodium hydroxide in sufficient quantity to adjust pH to 5.2 in 3.0 mL Water for Injection.