Hydrocodone or dihydrocodeinone is a semi-synthetic opioid derived from two of the naturally occurring opiates, codeine and thebaine. Hydrocodone is an orally active narcotic analgesic and antitussive. It is commonly available in tablet, capsule, and syrup form and is often compounded with other analgesics like paracetomol or ibuprofen. It is marketed, in its varying forms, under a number of trademarks, including Vicodin, Symtan, Anexsia, Dicodid, Hycodan (or generically Hydromet), Hycomine, Hycet, Lorcet, Lortab, Norco, Novahistex, Hydrovo, Duodin, Kolikodol, Orthoxycol, Mercodinone, Synkonin, Norgan, and Hydrokon. Hydrocodone was first synthesized in Germany in 1920 and was approved by the FDA on 23 March 1943 for sale in the United States under the brand name Hycodan.
As a narcotic, hydrocodone relieves pain by binding to opioid receptors in the brain and spinal cord. It can be taken with or without food as desired. When taken with alcohol, it can intensify drowsiness. It may interact with monoamine oxidase inhibitors, as well as other drugs that cause drowsiness. It is in FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks. In addition, a newborn of a mother taking the medication may exhibit breathing problems or withdrawal symptoms. Common side effects include dizziness, lightheadedness, nausea, drowsiness, constipation, vomiting, and euphoria. Some less common side effects are allergic reaction, blood disorders, changes in mood, mental fogginess, anxiety, lethargy, difficulty urinating, spasm of the ureter, irregular or depressed respiration, and rash.
Hydrocodone can become habit-forming, which leads to physical and psychological addiction, but the potential for addiction varies from individual to individual depending on unique biological differences. Sales and production of this drug have increased significantly in recent years, as have diversion and illicit use. In the U.S., pure hydrocodone and forms containing more than 15 mg per dosage unit are considered Schedule II drugs. Those containing less than or equal to 15 mg per dosage unit in combination with acetaminophen or another non-controlled drug are called hydrocodone compounds and are considered Schedule III drugs. Hydrocodone is typically found in combination with other drugs such as paracetamol, aspirin, ibuprofen and homatropine methylbromide. The purpose of the non-controlled drugs in combination is often twofold. 1) To provide increased analgesia via drug synergy. 2) To limit the intake of hydrocodone by causing unpleasant and often unsafe side effects at higher than prescribed doses (See Below). In the UK it is listed as a Class A drug under the Misuse of Drugs Act 1971. Hydrocodone is not available in pure form in the United States due to a separate regulation, and is always sold with an NSAID, acetaminophen, antihistamine, expectorant, or homatropine. The cough preparation Codiclear DH is the purest US hydrocodone item, containing guaifenesin and small amounts of ethanol as active ingredients. In Germany and elsewhere, hydrocodone is available as single-active-ingredient tablets as Dicodid (by analogy to the original manufacturer's other products Dilaudid and Dinarkon and others) available in 5 and 10 mg strengths.
The presence of acetaminophen in hydrocodone-containing products deters many drug users from taking excessive amounts. However, some users will get around this by extracting a portion of the acetaminophen using cold water, taking advantage of the water-soluble element of the drug. It is not uncommon for addicts to have liver problems from consuming excessive amounts of acetaminophen over a long period of time; taking 10,000 to 15,000 milligrams (10 to 15 grams) of acetaminophen in a period of 24 hours typically results in severe hepatotoxicity, and doses in the range of 15,000–20,000 milligrams a day have been reported as fatal. It is this factor that leads many recreational users to use only single entity opiates such as Oxycodone. One of the major problems today with the illicit use of hydrocodone, especially in younger populations, is that users may not be aware that hydrocodone pills contain acetaminophen. Consuming more than 4,000 milligrams of acetaminophen a day can cause liver damage, jaundice, and even liver failure if the drug is being taken in narcotic effect seeking dosages for an extended period of time.
Daily consumption of hydrocodone should not exceed 40 milligrams in patients not tolerant to opiates. However, the 2006 PDR (Physicians Desk Reference) clearly states that Norco 10, containing 10 milligrams of hydrocodone and 325 milligrams of APAP (viz., acetaminophen or paracetamol), can be taken at a dosage of up to twelve tablets per day (120 milligrams of hydrocodone). Such high amounts of hydrocodone are only intended for opiate-tolerant patients, and titration to such levels must be monitored very carefully. This restriction is only limited by the fact that twelve tablets, each containing 325 milligrams of APAP, puts the patient right below the 24-hour FDA maximum of 4,000 mg of APAP. Some specially compounded products are routinely given to chronic pain patients in doses of up to 180 mg of hydrocodone per day. Symptoms of hydrocodone overdosage include respiratory depression, extreme somnolence, coma, stupor, cold and/or clammy skin, sometimes bradycardia, and hypotension. A severe overdose may involve circulatory collapse cardiac arrest and/or death. Mixing hydrocodone with alcohol, cocaine, amphetamines, methylphenidate, benzodiazapines, barbiturates, and a number of other medication can have severe adverse reactions including but not limited to: heart failure, heart attack, respiratory distress, pulmonary failure, liver or kidney failure, jaundice, amnesia, seizures, blackouts and coma. Mixing acetaminophen with other NSAID analgesics like sulindac can cause serious damage to organs.
Combining an opioid such as hydrocodone with another analgesic can increase the effectiveness of the drug without increasing opioid-related side effects (e.g., nausea, constipation, sedation). Another argument for combining hydrocodone with acetaminophen is that it limits the potential for abuse. In tolerant users, hydrocodone can be taken in large doses relatively safely, but acetaminophen is fatally toxic to the liver in large quantities.