This study has a number of limitations, including reliance on prescription data as a measure of medication use, the use of emergency department visits as the primary outcome measure (so crashes that did not require medical services would not have been included), and the possibility of unmeasured confounders due to its observational design, and the fact that it was based on patients with commercial health insurance.
In a commentary discussing the results, the authors note how the use of short-acting medication may not be as effective at improving driving performance late in the evening; they say that “health care professionals should ensure that both the medication and dosage are optimal for a particular patient-driver, that the medication coverage is adequate for the particular patient’s driving routine, and that the medication prescribed is not responsible for worse driving as its effects wear off (rebound effect).”