The pharmacokinetics, a term used to describe the process of how a drug is absorbed, distributed within the body, metabolized and excreted, varies for all SSRIs. They are almost always administered orally. In general SSRIs are absorbed relatively slowly but completely usually taking between 3 to 8 hours. The active drugs in SSRIs bind to proteins, most often a1-acid glycoprotein, and are transported through the bloodstream and metabolized in the liver to varying degrees.