Which iontophoresis medication is used for pain and what polarity should it have?

• A. Lido (+) pain
• B. DEX (-) inflammation
• C. Saline (-) scars
• D. Acetic Acid (-) calcifications

Answer: (A)

Delivering drugs via iontophoresis depends on the drug’s electrical charge. Positively charged medications are driven into tissue by the positive electrode (the anode), because like charges repel and push the ions away into the body. For pain control, lidocaine is used because it’s a local anesthetic that is positively charged in solution, so applying positive polarity effectively delivers it to the painful area.

So, lidocaine with positive polarity is the best choice for pain relief in iontophoresis. The other options point to different targets (inflammation, scar tissue, calcifications) and involve drugs with different charges, which is why they’re not used for pain in this context.