How long will medication stay in my body after I stop taking it?
The length of time medication remains in the body depends on the type of medication. The speed at which it is removed is measured in “half-lives.” A half-life is the amount of time it takes for the level of medication in the blood to fall by half. Medications have a wide range of half-lives. For example, some are as low as 1 1/2 hours and others can take over 100 hours. Mothers who take medication that is not safe during breastfeeding can generally resume breastfeeding after five half-lives. At that point, only 3% of the starting dose will be present. If the drug has a half-life of three hours, the mother could typically resume breastfeeding after five half-lives, or 15 hours. More toxic chemotherapy drugs require a minimum of seven half-lives.