bactrim -- is it an effective toxoplasmosis prophylaxis

Question

A few years ago I had toxoplasmosis -- since then I have been on a maintenance dose of sulfadiazine,daraprim,and leucorvin calcium. My dr. said this prophylaxis also covered me for pcp. I went off the drugs a few months ago because of a skin reaction -- and as a result ended up getting pcp. My t-cells are 200. My Dr. told me that bactrim will protect me from getting toxo -- again and the drug doesn't seem to effect my skin. My concern is that the last time I got toxo -- 5 years ago I was on bactrim and it didn't protect me at that time my tcell were below 50. Should I worry if I only take bactrim -- I'm really don't want to get toxo -- again

Answer

There is some cross-activity between pyrimethamine(Daraprim)/sulfa used for toxo and trimethoprim/sulfa (Bactrim) used for PCP. Studies have shown that toxo therapy appears to protect people from PCP and that PCP prophylaxis with T/S protects people from getting toxo. That is not quite the same thing as showing that T/S adequately protects people from a relapse of toxo. Since your T cells are right at the margin, you might want to play it safe by taking maintenance therapy for your toxo that would also provide some protection against PCP. You don't say if it was figured out which medicine you reacted to, but reasonable options, depending on what was thought to have caused the rash, include: dapsone/pyrimethamine, clindamycin/pyrimethamine plus dapsone, or atovaquone. If your T cells go above 200 for at least 3 months and your viral load is well-controlled, you and your doctor may feel comfortable stopping the toxo maintenance therapy in the future.