Opportunistic Infections & Other Complications: Pneumocystis Carinii Pneumonia (PCP)


Opportunistic Infections & Other Complications: Pneumocystis Carinii Pneumonia (PCP)

Seattle Treatment Education Project (STEP) Perspective, Vol. 5, No. 2 - July 1993 * 127 Broadway E. Ste 200 Seattle, WA 98102
Laury McKean, RN

Although the incidence of Pneumocystis carinii pneumonia is declining due to more widespread use of prophylactic strategies, it is still a common opportunistic infection (po-b10-1489, po-b10-1441). One study assessed the reasons of the occurrence of PCP and found that most cases of PCP occurred in individuals who were unaware of their HIV status, particularly heterosexuals. Incidence was also high in individuals who knew their HIV status yet received either no or poor medical care, particularly intravenous drug users (PO-B10-1514). These findings exemplify the need for improvement in educating individuals on the importance of HIV testing and early medical care.

One of the main hurdles left to overcome regarding PCP prophylaxis is alternatives for individuals who are intolerant to TMP-SMX or dapsone. Presently, the standard alternative is aerosolized pentamidine. However, approximately 10% of individuals receiving aerosolized pentamidine experience breakthrough pcp. One study presented at the conference dealt with the dilemma of what to prescribe when individuals intolerant to TMP- SMX and dapsone experience breakthrough PCP despite aerosolized pentamidine prophylaxis. Out of 1151 individuals receiving aerosolized pentamidine, 131 experienced breakthrough pcp. Even though repeated breakthrough is inevitable once initial breakthrough PCP has occurred using aerosolized pentamidine, the majority of individuals were given only aerosolized pentamidine for prophylaxis once they recovered (WS-B14-2). This underscores the desperate need for further research in alternative choices such as aerosolized pentamidine combined with dapsone, TMP, or atovaquone, as well as desensitization to TMP-SMX.

Desensitization to TMP-SMX is becoming more widespread as increasing positive data emerges. Desensitization is a procedure in which individuals previously hypersensitive to TMP-SMX (as evidenced by fever and/or rash) are started on a very small amount of the drug and the dosage is gradually increased until the full dose is achieved. In one poster presented, 18 of 22 individuals were successfully desensitized. The procedure was stopped in four individuals due to the recurrence of rash or fever (PO-B10-1482). Although this was the only poster concerning desensitization presented at the conference, many similar studies are published in the medical literature. Desensitization should definately be considered by health care providers if prior hypersensitivity to TMP-SMX was not severe.

There were only a few posters concerning the treatment of pcp. One was a study comparing atovaquone (Mepron) to intravenous pentamidine in the treatment of mild to moderate PCP in 109 individuals. The study concluded atovaquone was as effective and was significantly better tolerated. However there was a trend towards more individuals failing therapy due to lack of response with atovaquone (po-b10-1421). One factor which may contribute to lack of response in some individuals using atovaquone is the drug's poor oral bioavailability. Currently the drug must be taken with a large amount of fat (preferably 23 grams with each dose) for optimal absorption. The manufacturer is presently working on a new liquid formulation with improved bioavailabilty.
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Always watch for outdated information. This article first appeard in 1993. This material is designed to support, not replace, the relationship that exists between you and your doctor.

Copyright © 1993 - Seattle Treatment Education Project (STEP) - All rights reserved. Noncommercial reproduction is encouraged. STEP is published four times a year by the Seattle Treatment Education Project, 127 Broadway East, 3rd Floor, Seattle, WA 98102.    Email: step100@aol.com  STEP web page

This information is designed to support, not replace, the relationship that exists between you and your doctor.
©1993. AEGIS.