<prompt> Drug of choice for pneumocystis carinii isDoxycyclineCotrimoxazoleTetracyclineDapsone  <response>: The treatment of choice for PCP is trimethoprim-sulfamethoxazole TMP-SMX, given either IV or PO for 14-21 days .TMP-SMX, which interferes with the organisms folate metabolism, is at least as effective as alternative agents and is better tolerated. Ref Harrison 19th edition pg 1019 Davidson edition23rd pg 587 