A urinalysis-based study of buprenorphine and non-prescription opioid use among patients on buprenorphine maintenance

Objectives: To understand the pattern of use of opioid-substitution therapy (OST) and opioid abuse among patients on buprenorphine maintenance using urinalysis. Materials and Methods: The study was conducted at a tertiary care de-addiction center. We reviewed the laboratory record of all consecutive urine samples sent for drug analysis over a period of 1 year. In all, 179 consecutive urine samples were included in the analysis. The chi-square test was used to compare opioid abuse among those testing positive and negative for buprenorphine on urinalysis. Additionally, in order to assess the potential impact of the prescribed induction and maximum dose of buprenorphine on the findings, we carried out the independent-samples t test. Level of statistical significance was kept at P<0.05 for all the tests. Results: Urinalysis failed to detect buprenorphine in 44.7% of the samples. Rate of detection of dextropropoxyphene was significantly higher among buprenorphine-negative samples (P<0.005). The prescribed induction dose of buprenorphine was significantly lower among those testing positive for heroin. This was found for both buprenorphine-positive (P<0.005) as well as buprenorphine-negative samples (P<0.005). Conclusions: These findings support the routine use of urine drug screening among individuals on OST.