Safe feeding window

Simple one-compartment pharmacokinetic model: maternal plasma concentration halves every half-life. After 5 × T½ about 3% remains. The calculator shows when that window opens. Applies to a single dose of drugs without milk accumulation.

Sources

NIH LactMed – Drugs and Lactation Database
Hale TW. Medications and Mothers' Milk, Springer 2019, ch. 1.
Rowland M, Tozer TN. Clinical Pharmacokinetics and Pharmacodynamics, 4th ed. Lippincott 2011 (single-compartment model).