To : Karen Re : Drug peaks and troughs A moms plasma and the milk compartment are normally in equilibrium, that means than when the moms plasma levels drop, the drug leaves the milk compartment and reenters the moms plasma. Drugs that enter milk, can also exit as well. This occurs for most, but not all, drugs. So a mom would not necessarily need to pump and dump her milk. Regards Tom Hale, Ph.D.