EFFECTS OF TIMING, DOSAGE, AND DURATION OF MORPHINE INTAKE DURING PREGNANCY ON THE AMOUNT OF MORPHINE IN MECONIUM IN A RAT MODEL

Meconium drug analysis is a new and sensitive test for detecting the i ntrauterine exposure of infants to drugs of abuse. To explore other po tential, diagnostic use of the test, we studied, in timed pregnant rat s, the relationship between timing, dosage, and duration of morphine a dministration to the dam and the concentration of morphine, analyzed b y radioimmunoassay, in their pups' meconium. The term 'meconium' refer s to both the intestine and its contents. Due to the minute size of th e pups' intestines, the intestinal contents were not separated from th e intestines. The mean morphine concentration in meconium was found to be significantly (p < 0.05) higher in the groups treated with a highe r morphine dose (10 vs. 5 mg/kg/day), longer duration of treatment (7- 20 vs, 18-20 days), or treated during the last week of gestation (14-2 0 vs, 1-6 or 7-13 days), We conclude that the concentration of a drug in the meconium is related to amount, timing, or duration of the drug exposure of the fetus, in utero. The quantitative analysis of drugs in the meconium, therefore, provides added information which enhances th e diagnostic use of the test.