Antibodies to drugs as indicators of chronic drug use. An alternative to toxicological hair analysis.

An ELISA method for detection of specific antibodies to morphine-protein conjugate (MPC) in humans and animals was elaborated. In humans, antibodies could be detected predominantly as the IgM class of immunoglobulins. Elevated levels of such antibodies were found in about 50% of opiate addicts and morphine-treated rats. In the case of prolonged and regular drug use with the time since the last drug intake not exceeding 2 months, elevated levels of antibodies to MPC were detected more frequently (up to 75%). Antibodies to MPC, detected in opiate addicts, were specific to MPC, morphine and beta-endorphin. A similar approach was applied to the detection of antibodies to ephedrone (amphetamine-like derivative of ephedrine) in case of its chronic use.