QUESTION: I do not know if DMSA is contraindicated in people with sulfa allergy, I get mixed information?
ANSWER: Mixed information because people confuse “sulfa” and “thiol” issues and they are not always the same but do crossover. ‘Sulfa’ allergy is a true Type-1 reaction to specifically the sulfonamide molecule and close relatives (as in thiazide drugs). It has little to do with the sulfur moiety in the sulfonamide molecule. Thiols (such as sulfur bearing compounds ALA, NAC, DMSA, DMPS, Glutathione…) cause different reactions usually due to slow SUOX function and other downstream metabolic issues in the processing of the sulfites.
SO One may have terrible thiol reactions and actually have no issue with sulfonamides, and vice versa. Clinically what we do is: if one has a documented thiol issue we support SUOX and re-try the thiol later. If a Sulfanomide allergy we continue with thiol therapy but start low in case they are one of those cross reactors (which is rare but not unheard of).
