Figure 1

Effect of Loratadine Dose and Exposure Time on Response to Radiation. (A) Cells were treated with 75 μM loratadine for various times prior to irradiation to 6 Gy. The radiation modifying effect increased with exposure time. Toxicity of loratadine alone was minimal until exposure exceeded 18 hrs. (B) Cells were treated with loratadine (0, 10, 25, 50, 75, 150, 300, and 450 μM) for 24 hrs prior to irradiation. A radiation modifying effect was only observed with a 75 μM dose. Toxicity of loratadine alone increased with dose and 100% of the cells were killed at doses above 75 μM (data not shown). Cell survival is corrected for the toxicity of loratadine alone. The figure represents the mean ± SD for 3 experiments.