Vicodin / Hydrocodone
Hydrocodone was first synthesized in Germany in 1920. It is an semi-synthetic opioid analgesic (pain killer) made from the opium derivatives codeine and thebaine.
Although not as strong as morphine or oxycodone is is still considered to be dependence causing if taken for long enough.
In addition to taking LSD to try and cure his migraine in the episode 'Distraction', Dr. Gregory House (played by Hugh Laurie in the Fox TV show 'House') is dependent on Vicodin.
Many of House's drug issues mirror those of Sherlock Holmes (House - Holmes / Homes) dependence on both morphine and cocaine - both return to heavy drug use when there are no cases to deal with.