PCP = Pneumocystis carinii pneumonia; HIV = human immunodeficiency virus; NA = not available because HIV disease has significant mortality over this time range, the proportions after 1 yr present very small sample sizes, and data are unreliable. All proportions are calculated with censoring at time of death or withdrawal.

All references are preliminary communications; except changes in data with confirmation and follow-up or both.

aThe higher relapse rate on zidovudine (AZT) may be artifactual because of delay to start zidovudine therapy from episode of PCP.

b Represent confirmed episodes of PCP on a 300-mg dose of aerosolized pentamidine every 4 wk.

The European trial studied patients without a history of PCP. In this primary-prophylaxis trial, 223 patients seropositive for HIV were randomized to receive 300 mg pentamidine isethionate or 300 mg sodium isethionate by Respirgard II nebulizer every 28 days [38]. Another entry criterion was a CD4 cell count of less than 200 cells/mm3. The study was terminated with a mean follow-up of about 1 yr, when 23 cases of PCP had occurred in the placebo group and eight cases in the treatment group. These investigators concluded that aerosolized pentamidine was about 60-70% effective in preventing the first episode of PCP. However, three of the eight events in the treated group occurred in the first 2 mo of the study, suggesting that the patients may have had prodromal PCP at the time of randomization or that a loading dose may be appropriate. This study confirmed the wisdom of the early FDA approval of primary prophylaxis without specific data in this patient group.

Aerosolized pentamidine does not provide perfect prophylaxis. Nevertheless, most relapses are mild, with a case fatality rate of less than 5% [36]. Lowery and colleagues reviewed the radiographic pattern of relapse in patients on a 30-mg dose of aerosolized pentamidine and found a striking increase in upper lobe relapses, a finding that correlates with the predicted deposition of most of the drug in the lower lobes [39]. The use of a higher, 300-mg dose may ameliorate this problem, but breathing patterns that encourage apical deposition, such as occasional exhalation to residual volume and supine position, may also decrease apical reoccurrence [40,41]. Contraindicated is breath holding at increased lung volumes, which would decrease apical deposition.

Comparisons of the performance of two nebulizers in the delivery of pentamidine and their effectiveness in a community-based clinical trial have been reported [42]. The systems employed were the Respirgard II and the Fisoneb. Both systems provided comparable protection against PCP. The study supported the effectiveness of aerosolized pentamidine as a solid second-line prophylaxis for HIV-infected individuals who are tolerant to trimethoprim/sulfamethoxazole or dapsone.

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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