From the Web site, drug-addiction.com
Hydrocodone is an orally active analgesic and antitussive Schedule II narcotic that is marketed in multi-ingredient Schedule III products.
Hydrocodone has an analgesic potency similar to or greater than that of oral morphine. Sales and production of this drug have increased significantly in recent years (a four-fold increase between 1990 and 2000), as have diversion and illicit use. Trade names include AnexsiaA, HycodanA, HycomineA, LorcetA, LortabA, TussionexA, TyloxA, VicodinA, and VicoprofenA. These are available as tablets, capsules, and/or syrups. Generally, this drug is abused by oral rather than intravenous administration. Currently, about 20 tons of hydrocodone products are used annually in the United States.
Hydrocodone abuse has been escalating over the last decade. There has been large scale diversion of hydrocodone. For example, an estimated 7 million dosage units were diverted in 1994 and over 11 million in 1997. In 1998 there were over 56 million new prescriptions written for hydrocodone products and by 2000 there were over 89 million. From 1990 the average consumption nationwide has increased by 300 percent. In the same period there has been a 500 percent increase in the number of Emergency Department visits attributed to hydrocodone abuse with 19,221 visits estimated in 2000. In 1997, there were over 1.3 million hydrocodone tablets seized and analyzed by the DEA
laboratory system. A recent petition submitted to the DEA has requested a review of the control status of all hydrocodone-containing products.

There are over 200 products containing hydrocodone in the U.S. In its most usual product forms, hydrocodone is combined with acetaminophen (Vicodin, Lortab), but it is also combined with aspirin (Lortab ASA), ibuprofen (Vicoprofen), and antihistamines (Hycomine). Both tablet and liquid forms of hydrocodone are available (e.g., Tussionex)

Hydrocodone is abused for its opiate-like effects. It is similar to morphine in relieving abstinence symptoms from chronic morphine administration. The Schedule III status of hydrocodone-containing products has made them available to widespread diversion by “bogus call-in prescriptions” and
thefts. Three dosage forms are typically found (5, 7.5, and 10 mg) and their behavioral effects can last up to 5 hours. The drug is most often administered orally. The growing awareness and concern about AIDS and blood-borne pathogens easily transmitted by syringe needle use, has made the oral bioavailability of hydrocodone attractive to the typical opiate abuser.

As with most opiates, the adverse effects of hydrocodone abuse are dependence and tolerance development. Its co-formulation with acetaminophen has also increased the likelihood of acetaminophen-induced hepatic necrosis with high dose acute dosing, but slow escalation of dose over time seems to
protect the liver during high dose chronic exposures seen with this drug.