ABSTRACT
INTRODUCTION: Despite the fact that buprenorphine is effective, well tolerated and due to its pharmacological profile a very safe drug, the impact of long-term buprenorphine substitution therapy on complex psychomotor and cognitive function predicting driving ability is not yet clear. Therefore, a prospective comparison between patients receiving sublingual buprenorphine and a control group of untreated, healthy volunteers was performed. METHODS: Treated and untreated subjects were matched for age and sex, with three control subjects selected for every buprenorphine patient. Patients using unreported drugs were included in the intention-to-treat (ITT) analysis; the remaining patients were analysed as the per-protocol (PP) group. The test battery comprised the assessment of: performance during stress, visual orientation, concentration, attention, vigilance and reaction time. The primary endpoint was defined as the sum of the relevant scores of the tests after z-transformation of the individual scores. RESULTS: 30 patients with sublingual buprenorphine treatment (7.7±3.9 mg per day) were matched to 90 controls. 19 patients were excluded from the PP-analysis because of additional unreported drug intake. Significant non-inferiority could be demonstrated for the PP-group (p<0.05) as well as for the ITT-group (p<0.001). CONCLUSION: Patients receiving a stable dose of sublingual buprenorphine showed no significant impairment of complex psychomotor or cognitive performance as compared to healthy controls. However intake of illicit drugs as well as the lack of social reliability are major problems in this specific patients group. Despite of the absence of a relevant impact of the drug on driving ability, those patients do not seem to be qualified for getting their driving license.
Subject(s)
Attention/drug effects , Buprenorphine/therapeutic use , Cognition/drug effects , Narcotic Antagonists/therapeutic use , Opioid-Related Disorders/drug therapy , Psychomotor Performance/drug effects , Adult , Automobile Driving , Buprenorphine/administration & dosage , Buprenorphine/adverse effects , Chronic Disease , Control Groups , Female , Humans , Male , Middle Aged , Narcotic Antagonists/administration & dosage , Narcotic Antagonists/adverse effects , Opioid-Related Disorders/rehabilitation , Prospective Studies , Reaction Time/drug effects , Time Factors , Visual Perception/drug effectsABSTRACT
OBJECTIVE: Development of a rational and enforceable basis for controlling the impact of cannabis use on traffic safety. METHODS: An international working group of experts on issues related to drug use and traffic safety evaluated evidence from experimental and epidemiological research and discussed potential approaches to developing per se limits for cannabis. RESULTS: In analogy to alcohol, finite (non-zero) per se limits for delta-9-tetrahydrocannabinol (THC) in blood appear to be the most effective approach to separating drivers who are impaired by cannabis use from those who are no longer under the influence. Limited epidemiological studies indicate that serum concentrations of THC below 10 ng/ml are not associated with an elevated accident risk. A comparison of meta-analyses of experimental studies on the impairment of driving-relevant skills by alcohol or cannabis suggests that a THC concentration in the serum of 7-10 ng/ml is correlated with an impairment comparable to that caused by a blood alcohol concentration (BAC) of 0.05%. Thus, a suitable numerical limit for THC in serum may fall in that range. CONCLUSIONS: This analysis offers an empirical basis for a per se limit for THC that allows identification of drivers impaired by cannabis. The limited epidemiological data render this limit preliminary.
