The speed in which a drug is eliminated from the body is determined by various factors, such as your age, the condition of your kidneys and liver, as well as the drug(s) you took.

Each drug has something known as a half-life, which is how long it takes the body to get rid of half of the dose of a particular drug. If you stopped taking the drug, then it will keep eliminating half until there is nothing left.

The general rule of thumb is to multiply the drug’s half-life by 5.5 for a rough estimate of how long it takes to leave the body. You can find that information in the drug manufacturer’s prescribing information.

Using Harvoni (ledipasvir/sofosbuvir) as an example, ledipasvir has the longer half-life in this combination, at 47 hrs. Using the formula, it comes to 258.5 hrs or almost 11 days.

Most of the other hep C drugs are eliminated more quickly. Ribavirin has a long half-life and may take 39 days or more.