Described herein are transdermal parasiticidal formulations and methods of treatment and use. wherein the formulation is not only able to deliver an agent or agents through the skin layer, but is able to do so through wool, dirt and/or a sebum layer on the skin if such layers are present The transdermal parasiticidal formulation may be a solution including a therapeutically effective amount of levamisole anthelmintic agent dissolved in a solution including isopropyl myristate and D-limonene. This base formulation is highly compatible with other compounds and various other actives may be added to this formulation.
