Tramadol

Tramadol is a molecule that is significant in our world today. It has two chiral centers which are labeled in the picture below. Stereochemistry is also assigned where the OH group on the first chiral center is pushed forward, and the hydrogen on the second chiral center is pushed back. 

Tramadol  is prescribed to adults who experience mild to severe pain. It is an extended release medicine, therefore it is relevant to patients who experience pain around the clock. Tramadol is an opiate agonist. This is a class of medicine which changes the way a person experiences pain by increasing the neural synaptic levels of norepinephrine. 

Sources: 

http://www.nlm.nih.gov/medlineplus/druginfo/meds/a695011.html

http://bja.oxfordjournals.org/content/88/4/563.full