Comparative efficacy of two doses of nebulized colistimethate in the eradication of Pseudomonas aeruginosa in children with cystic fibrosis.
BACKGROUND
Cystic fibrosis (CF) affects the respiratory and digestive systems. It evolves toward deterioration of pulmonary function through colonization with Pseudomonas aeruginosa. There is no consensus with respect to its eradication. Nebulized colistimethate is used for eradication treatment, but the optimal dose and duration is yet to be determined.


OBJECTIVE
To compare the efficacy of two doses of nebulized colistimethate (30 mg versus 75 mg twice daily) for the eradication of P aeruginosa in children with CF and intermittent colonization.


METHODS
A cohort study with both historical (30 mg) and prospective (75 mg) arms was conducted from 1999 to 2003. Medical records were used to collect data.


RESULTS
Eighty-one patients were recruited in the retrospective group, for a total of 111 treatment courses. Twenty patients were recruited in the prospective group, for a total of 20 events. There was no statistically significant difference in the rate of eradication of P aeruginosa at days 28 and 90, neither when comparing the doses of colistimethate nor duration of treatment. There was a statistically significant difference (P=0.004) between days 1 and 90 in all analyzed subgroups (regardless of dose or duration of treatment) for forced vital capacity only. In the group of patients in whom eradication was achieved at day 28 (after receiving a three-week treatment course of colistimethate), 50% of patients developed a new infection 5.75 months later, on average, regardless of the dose administered. In the group of patients who achieved eradication at day 90 (after receiving a 15-week treatment course of colistimethate), 50% of the 14 patients developed a new infection after an average period of 7.3 months (P=0.28).


CONCLUSIONS
There is no difference in the efficacy between a 30 mg dose and a 75 mg dose of colistimethate for P aeruginosa eradication in children with CF and intermittent colonization.
Department of Pharmacy, CHU Sainte-Justine, Montreal, Canada.
Marie-Sophie
MS
Brochet
Anne-Cathrine
AC
McDuff
Jean-François
JF
Bussières
Elaine
E
Caron
Geneviève
G
Fortin
Denis
D
Lebel
Jacques-Edouard
JE
Marcotte
D000293:Adolescent; D002353:Carrier State / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D003091:Colistin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D003550:Cystic Fibrosis / Q000150:complications / Q000382:microbiology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007223:Infant; D053208:Kaplan-Meier Estimate; D009330:Nebulizers and Vaporizers; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D055502:Secondary Prevention
C004691:colistinmethanesulfonic acid; D003091:Colistin