The Effect of Benzalkonium Chloride on the Paradoxical Bronchoconstriction with Antiasthmatic Respirator Solution / 소아알레르기및호흡기학회지

Recently, some cases of paradoxical bronchoconsthction with the use of nebulized antiasthmatic respirator solutions have been reported. This study was performed to determine whether benzalkonium chloride, contained in several antiasthmatic respirator solutions as a preservative, may cause paradoxical bronchoconstriction. This was accomplished by comparing the FEV(1) change after Ventolin (benzalkonium containing salbutamol) nebulization with the FEV(1) change after Respolin autohaler (benzalkonium free sa1butamol) inhalation within the same patient. This study consisted thirty patients with stable asthma who regularly attend the allergy clinic at Wallace Memorial Baptist Hospital. Patients were excluded from the study if they had respiratory disease or were taking any other medications. The results are as knows: 1) The baseline FEV(1) in the Ventolin group was 73+/-1O(% predicted) and 74+/-10(% predicted) in the Respolin autohaler group, showing no statistical difference in baseline FEV(1) between the two groups. 2) FEV(1) was decreased in 9 subjects(3096) after Ventolin nebu1ization and in 1 subject(3396) after Respolin autohaler inhalation, showing that the incidence of FEV(1) fall was higher in the Vento1in group than in the Respo1in autohaler group(p<0.OO5, one-tailed t-test). 3) Considering the cases with increased FEV(1) after inhalation, FEVl was increased by 9+/-7 (% predicted) in the Vento1in group and 7+/-5(% predicted) in the Respolin autohaIer group, suggesting that bronchodi1ator effects of both medications are similar. 4) Mild coughing occurred in 4 subjects(13396), and mild chest tightness in 1 subject(33%) in the Ventolin group. These symptoms resolved without any treatment. No side effects were reported by subjects in the Respolin autohaler group. In conclusion, these results strongly suggest that the paradoxical bron-choconstriction occurring with nebulized antiasthmatic respirator solutions is due to the ingredient benzalkonium chloride. Therefore we recommend that a benzalkoniulm free salbutamol product should be used for asthmatic patients, or if a product such as Ventolin which contains benza1konium chloride must be used, we recommend that it should be administered cautiously.

Evaluation of Theophylline Dosing Equation in Korean Infants with Bronchial Asthma / 소아알레르기및호흡기학회지

It has been reported that theophylline clearance is lower in Korean infants than in Americans, suggesting that dose requirements for theophylline in Korean infants will be 1ower than those in Americans. Therefore, we reviwed patients charts retrospectively to formulate the new theophylline dosing equation appropiate to Korean infants. We reviewed patient charts of 111 asthmatic infants who received intravenous aminophy1line and oral theophylline in Wa1lace Memorial Baptist Hospital. We set the therapeutic serum concentration at 5-15microgram/ml in Korean infants based on response rate to theophylline therapy, which is supported by National Institute of Health Expert Panel Recommendations. Doses required to achieve a therapeutic serum concentration increased with age. The mean dose among the infants less than 4 months of age was 578+/-154mg/kg/day and increased to 10.12+/-1.78mg/kg/day after 8 months (p<0.0001). The relationship between age and dosage requirements can be expressed by the least squares determination of the linear regression :Dose (mg/kg/day) = 557 + 0.14 X (age in weeks). The coefficient of correlation for this relationship is 0.67(p<0.0001). Half-lives of elimination among the infants studied correspondingly decreased with age. In conclusion, this study showed that the relationship between age and dosage requirements in Korean infants may be different from those in Americans. Therefore, we strongly suggest that it is required to formulate a new theophylline dosing equation appropriate for Korean infants through well-designed prospective studies.