Testing human hair for drugs of abuse. i. individual dose and time profiles of morphine and codeine in plasma, saliva, urine, and beard compared to drug-induced effects on pupils and behavior

The time course of appearance of morphine and codeine in beard after single dose administration in two human subjects was monitored by radioimmunoassay and confirmed by gas chromatography/mass spectrometry. Both morphine and codeine appeared in beard approximately 78 days after drug administration at a time when drug levels in urine, plasma, and saliva were not detectable and drug-induced effects had disappeared. Drug levels in beard appeared to be dose-related suggesting that hair analysis can provide evidence of time and degree of drug exposure.