• accidents;
  • automobile driving;
  • drug prescriptions;
  • drug utilization;
  • risk assessment;
  • traffic


• Some commonly prescribed medications can be a hazardous to traffic safety.

• Fifteen categorization systems are currently available in Europe. However, none of these systems clearly reports the methodology that was followed in order to categorize medications that impair driving.

• None of the existing categorization systems are currently implemented at European level.


• This study describes standardized and harmonized criteria to categorize medications according to their potential to impair fitness to drive.

• This study proposes a European categorization system of medications that impair driving that covers all the most frequently prescribed medications.

• The proposed categorization system can be seen as a tool to improve prescribing and dispensing procedures of medications that impair driving as well as an instrument to make patients aware of the role medications play in traffic safety.

AIMS To illustrate (i) the criteria and the development of the DRUID categorization system, (ii) the number of medicines that have currently been categorized, (iii) the added value of the DRUID categorization system and (iv) the next steps in the implementation of the DRUID system.

METHODS The development of the DRUID categorization system was based on several criteria. The following steps were considered: (i) conditions of use of the medicine, (ii) pharmacodynamic and pharmacokinetic data, (iii) pharmacovigilance data, including prevalence of undesirable effects, (iv) experimental and epidemiological data, (v) additional data derived from the patient information leaflet, existing categorization systems and (vi) final categorization. DRUID proposed four tiered categories for medicines and driving.

RESULTS In total, 3054 medicines were reviewed and over 1541 medicines were categorized (the rest were no longer on the EU market). Nearly half of the 1541 medicines were categorized 0 (no or negligible influence on fitness to drive), about 26% were placed in category I (minor influence on fitness to drive) and 17% were categorized as II or III (moderate or severe influence on fitness to drive).

CONCLUSIONS The current DRUID categorization system established and defined standardized and harmonized criteria to categorize commonly used medications, based on their influence on fitness to drive. Further efforts are needed to implement the DRUID categorization system at a European level and further activities should be undertaken in order to reinforce the awareness of health care professionals and patients on the effects of medicines on fitness to drive.