Studying The Effects Of Drugs On Driving

Reducing the incidence of motor vehicle accidents (MVAs) that occur because of drug-impaired driving is a public health priority. There are more than 20,000 FDA-approved drugs on the market currently, many of which contain psychoactive or sedative pharmaceutical ingredients which could alter the ability to operate a motor vehicle. Systematically identifying drugs that may increase the potential for MVAs is a critical component in safe and effective drug development.

In 2015, the draft guidance detailing the FDA’s current thinking and expectations around how and when to assess a new drug’s ability to affect driving was released to address this concern. In November of 2017, after receiving industry feedback, the FDA finalized the guidance entitled Evaluating Drug Effects on the Ability to Operate a Motor Vehicle and maintained all of the key aspects of the draft guidance. The guidance proposes a tiered approach of pharmacological/toxicological, epidemiological, and standardized behavioral assessments to evaluate possible drug effects on driving, starting early in clinical development. The inclusion of these assessments represented a dramatic shift in the design of early phase studies as most early clinical studies only assessed self-reported adverse events related to cognition. The guidance requires direct measurement of the effects.

Not every drug will be required to undergo this tiered evaluation. First we must consider the conditions for use of the drug and the intended patient populations. For example, an anesthetic used for surgery will not need to undergo in-depth cognitive assessments, as long as the time-course of the pharmacokinetics shows that drug levels are minimal by the time patients leave the hospital. On the other hand, drugs intended for chronic (including chronic-intermittent) outpatient use by adults who drive will most likely need to be evaluated to assess their effects on driving, whether they are psychoactive or non-psychoactive. Although there is a focus on psychoactive drugs in the new guidance, there is also clear indication that special care is needed during the development of non-psychoactive drugs, since they can also indirectly impair the ability to drive.