Methadone and buprenorphine are commonly used as oral substitutes in opiate maintenance programs to treat persons who are dependent on heroin. During these programs, patients are not allowed to continue using illicit drugs. Abstinence can easily be monitored by urine tests with immunochemical methods. It is well known that the intravenous abuse of heroin substitutes like methadone or buprenorphine has become common as well. The methadone-prescribing physician has no opportunity to check whether the opiate maintenance treatment patient takes his substitution medicines orally as intended or continues with his intravenous misuse now substituting the methadone instead of injecting heroin. In Germany, substitutes are available as liquids and tablets that contain carbohydrates as adjuvants. Sucrose is used to increase viscosity in liquids, while lactose is needed for pressing tablets (e.g., Methaddict® and Subutex®). In case of oral ingestion, disaccharides are broken down into monosaccharides by disaccharidases in the small intestine. These monosaccharides are absorbed into the blood stream by special monosaccharide transporters. Disaccharidases do not exist in blood, thus sucrose and lactose are not split if substitute medicines are injected intravenously. Our assumption, therefore, was that they are excreted unchanged in urine. We investigated a method for the detection of disaccharides in urine as markers of intravenous abuse of substitutes. Urine samples of 26 intravenous substitute abusers showed all positive results for lactose (76.9%) and/or sucrose (73.1%). The method is assumed to be useful to detect intravenous abuse of substitutes.
