Which current modality is typically used for iontophoresis?

• A. Direct current
• B. Symmetrical biphasic
• C. High voltage galvanic
• D. Pulsed biphasic

Answer: (A)

Iontophoresis relies on a steady, unidirectional electric current to push charged drug ions through the skin. Using direct current provides a constant electromotive force, so ions move in one direction from the delivery electrode into underlying tissues over the treatment period. If the current were alternating or pulsed biphasic, the polarity would reverse during the cycle, causing ions to migrate back and forth and resulting in little net drug delivery. High voltage galvanic setups aren’t the standard because iontophoresis typically uses low-amplitude direct current to maintain safe, controlled, and predictable dosing.