Screening for Illicit Drug Use in Drug Development Studies

Abstract

Increased attention is being focused on illicit drug use in the general public, but little information exists on the pattern of illicit drug use for volunteers for Phase I. The Upjohn Research Clinics, Kalamazoo, MI, conducted a retrospective survey of the incidence of positive drug screens found in the subject population of Phase I studies initiated between 1987 and 1989. Research subjects were recruited from a pool of 8,052 males and females over the age of 17 years. The use of illicit drugs was recorded for 621 (7.7%) of these subjects.

There was a total of 99 studies of which only 57 (58%) actually required drug screens. Of these studies with drug screens, 17,033 tests were completed with 377 tests (1.4%) in 291 individual subjects reporting positive for illicit drugs including cannabinoids, amphetamines, cocaine, opiates, benzodiazepines, and barbiturates. Most but not all studies requested screening for all six drugs listed.

The drugs encountered in decreasing order of frequency (total number of requested individual tests; number and percent of positive tests) were: cannabinoids (n = 2,921; 168, 5.8%), amphetamines (n = 3,066; 110, 3.6%), barbiturates (n = 3,039; 35, 1.2%), cocaine (n = 3,176; 36, 1.1%), opiates (n = 1,861; 18, 1.0%) and benzodiazepines (n = 2,970, 10, 0.3%).

The number of overall research studies and the percent of studies requiring drug screens has remained relatively constant over the last three years (1987, 35, 57%; 1988, 35, 60%; 1989, 29, 59%). Conclusion: The frequency and pattern of illicit drug use mirrors the general population. Recommendations are made as to how to more effectively screen for polysubstance use (eg, alcohol consumption plus illicit drugs) or how to monitor illicit drug use while subjects are participating in clinical trials.