A device (12) and method are provided for percutaneous transdermal delivery of a potent pharmacologically active agent. The agent is dissolved in water to form an aqueous coating solution having an appropriate viscosity for coating extremely tiny skin piercing elements (10). The coating solution is applied to the skin piercing elements (10) using known coating techniques and then dried. The device (12) is applied to the skin of a living animal (e.g., a human), causing the microprotrusions (10) to pierce the stratum corneum and deliver a therapeutically effect dose of the agent to the animal.