Iontophoresis uses which type of electrical current?

• A. Direct current
• B. Alternating current
• C. Pulsed current
• D. No current

Answer: (A)

Iontophoresis relies on a steady, unidirectional electric field to move charged drug ions through the skin. Direct current provides that constant, one-way push, creating a continuous driving force that pushes ions from the delivery electrode into the tissues. If the current were alternating, the field would reverse direction repeatedly, canceling net ion movement and dramatically reducing or stopping delivery. A pulsed current can deliver bursts of current but doesn’t provide the same steady delivery as a continuous direct current, and having no current means there’s no driving force at all. The rate of ion transport is proportional to the current, so maintaining a direct, constant current is essential for predictable dosing.