THE EFFECT OF CODEINE IN ANTI-COUGH SYRUP ON MORPHINE SCREEN

Background: Codeine is a lawfully permitted ingredient of anti-mid and anti-cough medicine that is readily available to the public at drug stores In Taiwan. Drug abusers often use it as a substitute for morphine while out of heroin and try to make an excuse to evade the law and say that they have only taken anti-cough syrup when morphine is detected in their urine. The purpose of this study is to try to propose criteria for codeine intake using a multiple lower dose model in normal therapeutic situations. Methods: Ten healthy volunteers each received, in two days, a total of 8 doses of cough syrup containing 4.5 mg of codeine per dose. Urine specimens were collected regularly during and in 3 days after syrup use. The urine specimens were analyzed by EIA screening test and GC-MS confirmation test. Results: Positive screen was noted during syrup use and 18-30 hour after the last dose of medication. The ratios of morphine to codeine were all less than one during syrup use and 12 hour after the last dose of syrup. Only 3.1% of the urine specimens, the ratio of the concentrations of morphine to codeine were between I and 3 when the concentrations of morphine and codeine were both very low i.e. below the cut-off values. Conclusion: The results may be used as a reference for the interpretation of urine analysis after the intake of multiple doses of anti-cough syrup with codeine. The criteria for codeine intake may be proposed as codeine concentration larger than 300 ng/mL and the ratio of morphine to codeine to be less than 3.
Hsu C, Hung D, Yang D. Division of Toxicology, Emergency Department, Taichung, Taichung Veterans General Hospital, [...]