Well, 'Love and Other Drugs' isn't based on a real-life event. The plot and characters were created for the film to engage the audience and tell a compelling fictional tale.
I'm not entirely sure which specific 'bear on drugs' true story you are referring to. There could be various anecdotes or real - life incidents involving bears and drugs in different contexts, such as in nature where a bear might accidentally ingest drugs left in the wild, or in some strange and perhaps unethical human - bear interaction scenarios related to drug use.