Drowsiness following the administration of Mepivacaine is usually a sign of a high blood level of the drug and may occur as a consequence of rapid absorption. Cardiovascular manifestations are usually depressant and are characterized by bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest. Signs and symptoms of depressed cardiovascular function may commonly result from a vasovagal reaction, particularly if the patient is in an upright position. Less commonly, they may result from a direct effect of the drug. Failure to recognise the premonitory signs such as sweating, a feeling of faintness, changes in pulse or sensorium may result in progressive cerebral hypoxia and seizure or serious cardiovascular catastrophe.
Management consists of placing the patient in the recumbent position and ventilation with oxygen.
These are characterized by cutaneous lesions, urticaria, edema or anaphylactoid reactions. Allergic reactions as a result of sensitivity to Mepivacaine are extremely rare, and if they occur, should be managed by conventional means. The detection of sensitivity by skin testing is of doubtful value. Resuscitation equipment, oxygen and other resuscitative drugs should be available for immediate use. The lowest dosage that results in effective anaesthesia should be used to avoid high plasma levels and serious adverse effects.