Influence of low temperature on bronchodilatation induced by terbutaline administered by metered dose or dry powder inhalers in asthmatics.

Low temperatures may affect dose delivery efficacy and clinical effectiveness of medication aerosols. In this study we examine the effect of cold ambient temperature on the bronchodilatation produced by terbutaline delivered from a chlorofluorocarbon pressurized metered dose inhaler (pMDI) compared to a multi-dose dry powder inhaler (DPI). Fourteen stable asthmatics were studied on two consecutive days. On day 1, after measuring FEV1 at room temperature (22 degrees C), each patient was randomized to receive 500 microg of terbutaline delivered from pMDI or DPI stored for 24 h at 22 degrees C with FEV1 recorded 20 min post-dose; then, patients were placed in a chamber at -10 degrees C, and af…