Influence of Pneumocystis carinii Pneumonia on Serum and Tissue Concentrations of Pentamidine Administered to Rats

SUMMARY Pentamidine Isethlonate was administered by the tracheal route to control rats and Immunodepressed rats with Pneumocystls carlnli pneumonia (PCP). The serum concentration of pentamidine base 20 min after the administration was higher In the PCP rats (309 ± 165 ng/ml) than In the control animals (71 ± 36 mg/ml; p < 0.001); 90 min aftar the Injection the proportion of the pentamidine administered was lower In the right lung of the PCP rats (29 ± 15%) than In the control rats (57 ± 23%; p = 0.038); the proportion of pentamidine In the left kidney was higher In the PCP rats (14 ± 4%) than In the control animals (4 ± 2%; p < 0.001).Respiratory clearance of 99mTc-DTPA, an Index of the permeability of the respiratory epithelium, was higher In the PCP rats (1.84 ± 0.42 %/mln) than In the controls (0.44 ± 0.11 %/mln; p < 0.001). We conclude that the more rapid diffusion of pentamidine from the alveolar lumen to the pulmonary circulation Is explained by the Increased aiveolocaplllary permeability as a result of pneumocystosls.