Chelation drug interactions

• Tetracyclines / Fluoroquinolones
  • Interaction: Bind multivalent cations ($C{a}^{2+},M{g}^{2+},F{e}^{2+}$) in Milk, Antacids, Iron pills. t
  • Result: $\downarrow$ Absorption (separate by 2 hrs).
• Penicillamine
  • Interaction: Inactivates Vitamin B6.
  • Result: Neuropathy, Sideroblastic anemia. Supplement B6.
• Dimercaprol (BAL)
  • Interaction: Formulated in Peanut Oil (Avoid in peanut allergy).
  • Contraindication: Do not give with Iron (toxic complex).
• Deferoxamine
  • Interaction with Vitamin C (Ascorbic Acid): Vit C increases iron availability/mobilization for chelation.
  • Risk: While it enhances excretion, co-administration can transiently ↑ cardiac iron toxicity leading to severe cardiac dysfunction.
• EDTA
  • Interaction: Non-selective chelation of serum Calcium.
  • Result: Fatal Hypocalcemia (Tetany). Must use Calcium Disodium ($CaN{a}_2$) form.