oxycodone

Oxycodone is an opioid analgesic medication synthesized from thebaine. Its name is derived from codeine - the chemical structures are very similar, differing only in that the hydrogen on the codeine is oxidised to a hydroxyl group, hence 'oxy' and the hydroxyl group from the codeine becomes a ketone group, hence 'oxycodone.' The third difference to codeine is the 7,8-dihydro-feature (Codeine has a double-bond between those two carbons).

It is effective orally and is marketed in combination with aspirin (Percodan, Endodan, Roxiprin) or paracetamol/acetaminophen (Percocet, Endocet, Roxicet, Tylox) for the relief of pain. More recently, ibuprofen has been added to oxycodone (Combunox). It is also sold in a sustained-release form by Purdue Pharma under the trade name OxyContin as well as generic equivalents, and instant-release forms Endone, OxyIR, OxyNorm, Percolone, OxyFAST, and Roxicodone. Roxicodone is available in 5, 15, and 30 mg tablets. OxyContin is currently available in 5, 10, 15, 20, 30, 40, 45, 60, 80 and 160 mg tablets (although note that not all of these dosages are marketed in the USA) and, due to its sustained-release mechanism, is 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. Outside the U.S. OxyContin is also available in a 5 mg tablet. On October 18, 2006, the FDA gave approval for three new dosage strengths, 15mg, 30mg, and 45mg. OxyNorm is available in 5, 10, and 20 mg capsules and tablets; also as a 1 mg/1 ml liquid in 250 ml bottles and as a 10 mg/1 ml concentrated liquid in 100 ml bottles.

In the United States, oxycodone is a Schedule II controlled substance both as a single agent and in combination with products containing acetaminophen, ibuprofen or aspirin.

Chemical structure

The chemical structure of oxycodone is the methylether of oxymorphone: 3-methyl-oxymorphone. It could also be described as 14-hydroxy-7,8-dihydro-codeinone. It is principally supplied as its hydrochloride salt: oxycodone hydrochloride.

Bioavailability

Oxycodone can be administered orally, intranasally, via intravenous/intramuscular/subcutaneous injection, or rectally. The bioavailability of intranasal administration averages between 46-47%, but can be as much as 75%. Oral oxycodone is the most efficient means of administration, having an absorption of 60-87%. Rectal administration yields the same results. Injecting oxycodone will result in a stronger effect and quicker onset.

Medical use

oxycodone/paracetamol tablets] tablets of varying dose] Percocet tablets (Oxycodone with acetaminophen) are routinely prescribed for post-operative pain control. Oxycodone is also used in treatment of moderate to severe chronic pain. Both immediate release oxycodone and sustained-release oxycodone are now available (OxyContin and OxyNorm in the UK. There is no evidence that oxycodone is more effective than any other opioid and 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.

The potency ratio between oxycodone and morphine is still uncertain. The manufacturers claim oxycodone is twice as potent as morphine, but most studies show a much lower potency of between 1.3 to 1.7 times more potent, with an approximate mean of 1.5 time greater potency.

Nausea, drowsiness, constipation, lightheadedness, rash or itchiness, dizziness, and emotional mood disorders are the most frequently reported side effects. Other side-effects can also include dry mouth and slightly decreased testosterone levels in men. Oxycodone accumulates in patients with renal or liver impairment and dose reductions may be needed.

As with all other Opioids tolerance and dependence are rarely problems when these drugs are taken by patients in pain and given with the support of specialist in pain or palliative care.

History

Oxycodone is an opioid agonist, and as such is a variation on an ancient theme beginning with the simple consumption or smoking of the alkaloid-bearing parts of Papaver somniferum, the opium poppy, first cultivated circa 3401 BC in lower Mesopotamia. Ancient Sumerians, Assyrians, Babylonians, and Egyptians found that smoking the extract derived from the seedpods yielded a pleasurable, peaceful feeling throughout the body. The Sumerians called the poppy plant "Hul Gil" or "joy plant". Cultivation and use spread quickly to the rest of the Levant and the Arabian Peninsula, eventually reaching India and China.

Oxycodone is a semi-synthetic opioid derived from the alkaloid thebaine, unlike most early opium-derived drugs which instead used the morphine or codeine alkaloids also found in the plant. Oxycodone was first synthesized in a German laboratory in 1916, a few years after the German pharmaceutical company Bayer had stopped the mass production of heroin due to addiction and abuse by both patients and physicians. It was hoped that a thebaine-derived drug would retain the analgesic effects of morphine and heroin with less of the euphoric effect which led to addiction and over-use. To some extent this was achieved, as oxycodone does not "hit" the central nervous system with the same immediate punch as heroin or morphine do and it does not last as long. The subjective experience of a "high" was still reported for oxycodone, however, and it made its way into medical usage in small increments in most Western countries until the introduction of the OxyContin preparation radically boosted oxycodone use.

Recreational use

The introduction of OxyContin in 1995 resulted in increasing patterns of abuse. Unlike Percocet, whose potential for abuse is limited by the presence of paracetamol, OxyContin contains only oxycodone and inert filler. Abusers simply crush the tablets, then either ingest the resulting powder orally, intranasally, via intravenous, intramuscular or subcutaneous injection (by dissolving the powder), or rectally to achieve rapid absorption into the bloodstream. Injection of OxyContin is particularly dangerous since it contains binders which enable the time release of the drug. Often mistaken as the time release, the outside coating of the pill is merely used as a color code for different dosage amounts,even though it can removed by saliva or wetness. The vast majority of OxyContin-related deaths are attributed to ingesting substantial quantities of oxycodone in combination with another depressant of the central nervous system such as alcohol or benzodiazepines. While high doses of oxycodone can be fatal to an opiate-naïve individual in and of itself, lethal overdoses of only oxycodone rarely occur. It was once thought that opioids would be less subject to recreational (ab)use when one or more additional analgesics are added, since, for example, the amount of paracetamol present in higher doses of Percocet causes stomach upset and liver damage. However, it has been demonstrated that abusers seeking the euphoric "high" are not deterred by these potential side effects or toxicities. Abusers soon discovered that extremely simple methods to separate the ingredients exist, particularly due to the widely disparate solubility of the alkaloids and analgesics in water ("cold water extraction").

Oxycodone Use]

Oxycodone has similar effects to morphine and heroin, and appeals to the same abuse community. Armed robberies of pharmacies where the robber demanded only OxyContin, not cash, have occurred. In some areas, particularly the eastern U.S., OxyContin has been the drug of greatest concern to enforcement authorities, although trustworthy data on the actual incidence of "Oxy abuse" have been difficult to establish.

Because oxycodone is highly regulated, when acquired illegally it is quite expensive. Black market prices in Washington, DC, and Portland, Maine, for example, have been reported to reach upwards of one dollar per milligram, though it is more typical to pay $50 for an 80-milligram tablet on the streets of Washington. In parts of Kentucky, particularly in Appalachia, the cost is nearly $1.25/mg. Legally acquired OxyContin is however rather expensive, costing as much as 400 US dollars for a normal month supply. Again, in mid-2006, brand-name or similar-quality generic (e.g., Watson, Purdue) eighty-milligram tablets sold for approximately nine dollars apiece whereas low-end generics (e.g., Teva, referred to in slang as "footballs" after their shape) scarcely pushed five dollars.

In Australia OxyContin is covered by the Pharmaceutical Benefits Scheme, and a patient can potentially get up to sixty tablets for as little as $4.90AUD in total. This has led to Federal tightening of restrictions from May 2006 (see Regulation below). The 20mg tablet can fetch $30AUD-$50AUD on the Gold Coast black market. As such there are professional "Doctor shoppers" making a tidy profit each week from OxyContin.

Like other opioids, oxycodone can be fatal at high doses or when combined with depressants such as alcohol or Benzodiazapines. Several documented fatalities from OxyContin abuse have been made public; however, these have done little to deter the combined use of the drug with other CNS depressants.

In early 2006 on the U.S. East Coast there were multiple anecdotal reports of "fake" OxyContin 80mg tablets, especially in Philadelphia and New York City. These fake OxyContin consisted mainly of sugar and were of poor quality, noting the distinct green color which differs from commercially made tablets. There have also been multiple reports of fake OxyContin 80mg tablets that contained Fentanyl.. The most commonly diverted dosages are the 40mg and 80mg strengths.

Manufacturer and patents

varieties.jpg|frame|left|Formulations containing oxycodone and other analgesics.] OxyContin was first introduced onto the market by Purdue Pharma L.P. in 1995. This pharmaceutical company was founded in 1892 in New York City, and is currently a privately owned company that operates solely within the United States. The different branches within this company include, Purdue Pharma L.P., The Purdue Frederick Company, Purdue Pharmaceutical Products L.P., and Purdue Products L.P. (www.pharma.com). It has multiple patents for their drug OxyContin, but has recently been involved in a series of on going legal battles deciding on whether or not these patents are valid. On June 7th, 2005, the United States Court of Appeals for the Federal Circuit upheld a decision from the previous year that some of Purdue’s patents for OxyContin could not be enforced. This decision allowed and led to the immediate announcement from Endo Pharmaceutical Holdings, Inc. that they would begin launching a generic version of all four strengths of OxyContin. Purdue, however, had already made negotiations with another pharmaceutical company (IVAX Pharmaceuticals) to distribute their brand OxyContin in a generic form. This contract was severed, and currently Watson Pharmaceuticals is the exclusive U.S. distributor of the generic versions of OxyContin Tablets. The agreement stipulates that "Purdue will manufacture and supply oxycodone HCI controlled-release tablets to Watson, which will market, sell, and distribute the authorized generic product in 10, 20, 40, and 80 milligram dosages in the United States".

Purdue Pharma L.P. is based out of Stamford, Connecticut, and is the site of the company’s headquarters. Manufacturing takes place at three different sites, which include: Purdue Pharmaceuticals L.P., a plant located in Wilson, North Carolina, The P.F. Laboratories Inc. in Totowa, New Jersey, and Rhodes Technologies L.P. located in Coventry, Rhode Island. Purdue Pharma L.P. also has research labs located in Cranbury, New Jersey. OxyContin is currently legally and illegally distributed throughout the U.S., Canada, and Mexico. Legal distribution takes place from the P.F. Laboratories Inc. in Totowa, New Jersey. Since the drug is a controlled substance, a prescription is required to obtain it, and is shown to be most frequently prescribed in the eastern U.S.. Purdue also exports OxyContin to wholesale distributors in Mexico and Canada. However, they have experienced increasing levels of illicit drug trafficking with the distribution outside of the U.S. that has led to certain responsive actions. The pill exported to Mexico is stamped with the letters "EX" instead of the customary "OC," and similarly the pills to Canada read "CDN." Purdue stopped exporting to Canada in 2001, and instead Canada imports the drug from a manufacturer in England. Despite these problems, OxyContin is one of the leading opioid painkillers on the market. In 2001, OxyContin was the highest sold drug of its kind, and in 2000, over 6.5 million prescriptions were written.

Chemistry

Oxycodone is made, commercially, from thebaine, an opiate alkaloid and minor component of opium. Uniquely, it has stimulating properties, as compared to other opiates, which is responsible for the subjective speedy quality of oxycodone some users report. The 14 hydroxy group increases potency by about 50% over hydrocodone. The 14 cinnamyl ester is 114x morphine in potency.

Regulation

Regulation of oxycodone (and opioids in general) differs according to country, with different places focusing on different parts of the "supply chain".

Regulation in Australia

In Australia a General Practitioner can prescribe for short term treatment without consulting another practitioner or government body. Ongoing treatment requires approval from their state Health Department.

Only twenty tablets are normally available per prescription on the Pharmaceutical Benefits Scheme, Australia's government-funded pharmaceutical insurance system. Prescriptions for larger quantities require prior approval from Medicare Australia. These prescriptions (i.e. for chronic pain or cancer patients) require the prescriber to have referred the patient to another medical practitioner to confirm the need for ongoing treatment with narcotic analgesics.

Pharmacists must record all incoming purchases of oxycodone products, and maintain a register of all prescription sales for inspection by their state Health Department on request. In addition details of all Pharmaceutical Benefits Scheme prescriptions for oxycodone are sent to Medicare Australia. This data allows Medicare Australia to assist prescribers to identify doctor-shoppers via a telephone hotline.

Regulation in Canada

In Canada, Oxycodone is a controlled substance under Schedule I of the Controlled Drugs and Substances Act (CDSA). Every person who seeks or obtains the substance without disclosing authorization to obtain such substances 30 days prior to obtaining another prescription from a practitioner is guilty of an indictable offence and liable to imprisonment for a term not exceeding seven years. Possession for purpose of trafficking is guilty of an indictable offence and liable to imprisonment for life.

Regulation in Hong Kong

In Hong Kong, oxycodone is regulated under Schedule 1 of Hong Kong's Chapter 134 Dangerous Drugs Ordinance. It can only be used legally by health professionals and for university research purposes. The substance can be be given by pharmacists under a prescription. Anyone who supplies the substance without a prescription can be fined $10,000(HKD). The penalty for trafficking or manufacturing the substance is a $5,000,000 HKD (Hong Kong dollar) fine and/or life imprisonment. Possession of the substance for consumption without license from the Department of Health is illegal with a $1,000,000 (HKD) fine and/or 7 years of jail time.

Regulation in the USA

Regulation of prescription drugs comes from many different areas. The Food and Drug Administration (FDA) approves drugs for medical use, as well as sets regulations for the marketing of drugs, including controlled substances. The Drug Enforcement Administration (DEA) on the other hand, receives its regulatory authority from the Controlled Substances Act (CSA) U.S.C. §§ 801-971, which "mandates that DEA prevent, detect and investigate the diversion of legally manufactured controlled substances while, at the same time, ensuring that there are adequate supplies to meet the legitimate medical needs in the United States".

Part of the regulation of prescription drugs is connected to their marketing and advertising. The FDA has authority over this sector under the Food, Drug, and Cosmetic (FD&C) Act and its implementing regulations. The Division of Drug Marketing, Advertising, and Communications (DDMAC) is "responsible for regulating prescription drug advertising and promotion," and has a "mission is to protect the public health by ensuring that prescription drug information is truthful, balanced, and accurately communicated". Simplified, Oxycodone is a schedule II controlled substance, which means to be filled there must be a written prescription which cannot have refills, nor can it be called in to a pharmacy by a physician.

Illicit Use

OxyContin is becoming an increasingly more publicized and known drug to the general public. The discovery of its recreational benefits has led to an illicit underground market. Due to acts such as pharmacy diversion and "doctor shopping" the drug is widely available to those without a prescription. The increased misuse of the drug has led to a higher number of emergency department mentions and deaths associated with oxycodone. Between 1994 and 2001 there was a reported 352% increase in ER visits related to all forms of Oxycodone usage

See also

• Opioids
• Codeine
• Drug addiction
• Thebaine

External links

• http://www.minervamedica.it/pdf/R02Y2005/R02Y2005N07A0451.pdf Oxycodone: Pharmacological profile and clinical data in chronic pain management minervamedica.it. Minerva Anestesiologica, 2005;71:451-60. pdf file
• http://www.drugs.com/pdr/percocet_tablets.html Percocet Drug Information from Thomson Healthcare database
• http://www.addictionsearch.com/treatment_articles/article/oxycodone-addiction_14.html Article on Oxycodone Addiction

• http://www.reuters.com/article/healthNews/idUSWBT00695020070510?src=051007_1225_DOUBLEFEATURE_ Oxycontin makers and executives plead guilty to coverup of dangers and addictive qualities

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Category:Morphinans Category:Semisynthetic opioids