Tuesday, May 09, 2006

PCP prophylaxis

User submitted question:

A patient of mine has RA-ILD and is on methotrexate. She will be on it for at least 3 months (or longer if it works). Do you prophylax for PCP with Bactrim in this case?

4 comments - CLICK HERE to read & add your own!:

Baleeiro said...

Is she on steroids as well or just MTX?

Baleeiro said...

I haven't looked this up recently but in the non-HIV, non-leukemia population, steroids (with or without other immunomodulators) are the biggest risk factor to developing PCP. I Pts who will be on chronic steroids on the equivalent of 30 mg/day of prednisone or more PCP prophilaxis should be considered. Especially if the steroids are coupled with cyclosporine or cyclophosphamide...
With MTX alone, I don't think there is as strong a recommendation to prophilaxe everyone.

none said...

She is on mtx alone. Thanks.

Jennings said...

Most studies I could find only reported cases where the steroid was in combination with some other underlying immunosuppressive process or another immunosuppressive drug.
One groups showed PCP risk in steroids alone; this group (Nihon Kokyuki Gakkai Zasshi. 43(12):725-30, 2005) analyzed 74 interstitial pneumonia patients receiving glucocorticoid therapy, of whom 7 patients developed PCP. At the time of PCP diagnosis, the average duration of the glucocorticoid therapy was 71 days and the average daily dose of prednison was 37 mg.
Another group specifically looked at HIV-negative patients with connective tissue disease on immunosuppressives. Most patients that developed PCP were on glucocorticoids (32/34, 94%) and 24 of that 32 were on combo therapy with either cytoxan (19) or methotrexate (n=5). But there is little that I could find showing that methotrexate alone increases the risk. I suppose any drug that causes lymphopenia would increase susceptibility.