Evaluation of subcutaneous injection of local anesthetic agents as a method of tick removal

The usefulness of subcutaneous injection of three local anesthetic agents to stimulate tick detachment in an animal model was evaluated. American dog ticks (Dermacentor variabilis) were placed on three New Zealand white rabbits and allowed to attach for 24 hours. Dead and unattached ticks were manually removed. Three local anesthetic agents were studied: 1% lidocaine (group A); 1% lidocaine with epinephrine 1:200,000 (group B); and 1% chloroprocaine (group C). For each group, a total of 0.25 mL of anesthetic agent was injected subcutaneously under the attached portion of each tick, resulting in formation of a 5- to 6-mm wheal. For all three anesthetic agents studied (group A, 34 ticks; group B, 28 ticks; group C, 31 ticks), none of the ticks spontaneously detached within 1 hour after injection. Subcutaneous injection of 1% lidocaine, 1% lidocaine with epinephrine, and 1% chloroprocaine are not effective methods for rapid tick removal in the animal model.