Thrombocytosis in the Offspring of Female Mice Receiving dl-Methadone 1

Abstract

Subcutaneous methadone administration (2.5 mg/kg/day) to female mice beginning 2 weeks prior to conception and continuing through weaning resulted in a significant increase in the number of circulating platelets (1650 × 10³ vs 1150 × 10³/mm³), an increase in marrow megakaryocytes per high power field (12.22 vs 9.59) and an increase in the percentage of young megakaryocytes (34.5 vs 28.4) in the offspring but not in the mothers. The effect was maximal 14 days after birth and diminished by 28 days. Injection of 5 mg/kg/day resulted in similar findings but the changes persisted for 35 days. These findings are consistent with those noted in the infants of human polydrug abusers and suggest that methadone plays a role in similar abnormalities in humans.