Oxycodone is an opioid analgesic medication synthesized from thebaine. It was developed in 1916 in Germany, as one of several new semi-synthetic opioids with several benefits over the older traditional opiates and opioids; morphine, diacetylmorphine(heroin) and codeine. It was introduced to the pharmaceutical market as Eukodal or Eucodal and Dinarkon. Its chemical name is derived from codeine - the chemical structures are very similar, differing only in that the hydroxyl group of codeine has been oxidized to a carbonyl group (as in ketones), hence the -one suffix, the 7,8-dihydro-feature (codeine has a double-bond between those two carbons), and the hydroxyl group at carbon-14 (codeine has just a hydrogen in its place), hence oxycodone.
Oxycodone is commercially made from thebaine, an opiate alkaloid and minor component of opium.
Side effects
The most commonly reported effects include constipation, euphoria, fatigue, dizziness, nausea, lightheadedness, headache, dry mouth, pruritus, and diaphoresis. It has also claimed to cause dimness in vision due to miosis. Some patients have also experienced loss of appetite, nervousness, anxiety, abdominal pain, diarrhea, dyspnea, and hiccups, although these symptoms appear in less than 5% of patients taking oxycodone. Rarely, the drug can cause impotence, enlarged prostate gland, and decreased testosterone secretion.
Withdrawal related side effects
There is a high risk of experiencing severe withdrawal symptoms if a patient discontinues oxycodone abruptly. Therefore therapy should be gradually discontinued rather than abruptly discontinued. Drug abusers are at even higher risk of severe withdrawal symptoms as they tend to use higher than prescribed doses. Withdrawal symptoms are also likely in neonates born to mothers who have been taking oxycodone or other opiate based pain killers during their pregnancy. The symptoms of oxycodone withdrawal are the same as for other opiate based pain killers and may include the following symptoms.
- Anxiety
- Nausea
- Insomnia
- Muscle pain
- Fevers
- Flu like symptoms
Dosage and administration
Oxycodone can be administered orally, intranasally, via intravenous/intramuscular/subcutaneous injection, by vapourizing/smoking or rectally. The bioavailability of oral administration averages 60-87%, with rectal administration yielding the same results. Injecting oxycodone will result in a stronger effect and quicker onset.
Oxycodone tablets, oxycodone with acetaminophen (paracetamol), are routinely prescribed for post-operative pain control. Tablets are available with 2.5, 5, 7.5, 10 or 15 mg of oxycodone and varying amounts of acetaminophen. Oxycodone is also used in treatment of moderate to severe chronic pain. Both immediate-release and sustained-release oxycodone are now available (OxyNorm and OxyContin in the UK). There are no comparative trials showing that oxycodone is more effective than any other opioid. In palliative care, morphine remains the gold standard. However, it can be useful as an alternative opioid if a patient has troublesome adverse effects with morphine.
OxyContin is available in 10 mg (white), 15 mg (black), 20 mg (pink), 30 mg (brown), 40 mg (yellow), 60 mg (red), and 80 mg (green) in the U.S. and Canada, and 160 mg (blue) in Canada only. Because of its sustained-release mechanism, the medication is typically effective for eight to twelve hours. The 160 mg tablets were removed from sale due to problems with overdose, but have been re-introduced for limited use under strict medical supervision. On October 18, 2006, the FDA gave approval for four new dosage strengths, to wit, 15, 30, 45, and 60 mg. After removing the colored outer coating, which weighs 8 mg (approx.), the mass of a standard 80 mg OxyContin tablet is 256 mg (approx.): 80 mg of oxycodone hydrochloride and 176 mg (approx.) of innactive material, making the formulation 31% pure (approx.) by weight.
Generic OxyContin was introduced in 2005 (80 mg) and 2006 (10, 20, and 40 mg). However, because of numerous law suits related to the addictive and abuse potential of the medicine, generic manufacture (alternatively reported as except by Dava) ceased on December 31, 2007. Oxycodone/APAP pills are still avaliable through prescription only.
The controlled (sustained)-release preparations are essential to provide a background plasma level of analgesia in anyone with persistent pain. The immediate release preparations are useful for breakthrough pain, which can break through the controlled-release baseline medication. There are no trials to show that one manufacturer produces a more effective oxycodone product than any other.
Abuse
Oxycodone is a drug subject to abuse. The drug is included in the sections for the most strongly controlled substances that have a commonly accepted medical use, including the German Betäubungsmittelgesetz III (narcotics law), the Swiss law of the same title, UK Misuse of Drugs Act (Class A), Canadian Controlled Drugs and Substances Act (CDSA), Dutch Opium Law (List 1), Austrian Suchtmittelgesetz (Addictives Act), and others. It is also subject to international treaties controlling psychoactive drugs subject to abuse or dependence.
The abuse of OxyContin and its generic equivalents has greatly increased since the introduction of the sustained-release form of oxycodone. Illegal distribution of OxyContin occurs through pharmacy diversion, physicians, doctor shopping, faked prescriptions, and robbery, all of which divert the pharmaceutical onto the illicit market. In Australia alone during 1999 and 2000, more than 260,000 prescriptions for narcotics and codeine-based medications were written to almost 9,000 known abusers at a cost of more than $750,000 AUD (approx $602,000 US). Purdue Pharma and its top executives pleaded guilty to felony charges that they misbranded and misled physicians and the public by claiming OxyContin was less likely to be abused, less addictive, and less likely to cause withdrawal symptoms than other opiate drugs. The company also paid millions in fines relating to aggressive off-label marketing practices in several states.
