Some medications are CYP2D6 inhibitors and reduce or even completely block the conversion of codeine to morphine. The most well-known of these are two of the selective serotonin reuptake inhibitors , paroxetine Paxil and fluoxetine Prozac as well as the antihistamine diphenhydramine Benadryl , and the antidepressant bupropion Wellbutrin, also known as Zyban. Other drugs, such as rifampicin and dexamethasone , induce CYP isozymes and thus increase the conversion rate.
CYP2D6 converts codeine into morphine, which then undergoes glucuronidation. Life-threatening intoxication, including respiratory depression requiring intubation, can develop over a matter of days in patients who have multiple functional alleles of CYP2D6, resulting in ultra-rapid metabolism of opioids such as codeine into morphine.
Evidence supporting the hypothesis that ultrarapid metabolizers may get greater analgesia from codeine due to increased morphine formation is limited to case reports. Guidelines released by the Clinical Pharmacogenomics Implementation Consortium CPIC advise against administering codeine to ultrarapid metabolizers, where this genetic information is available.
The CPIC also suggests that codeine use be avoided in poor metabolizers, due to its lack of efficacy in this group. Codeine and its metabolites are excreted almost entirely by the kidney, mainly as conjugates with glucuronic acid. Chemistry[ edit ] Relation to other opioids[ edit ] Codeine has been used in the past as the starting material and prototype of a large class of mainly mild to moderately strong opioids; such as hydrocodone in Germany , oxycodone in Germany , dihydrocodeine in Germany , and its derivatives such as nicocodeine in Austria.
In general, the various classes of morphine derivatives such as ketones, semisynthetics like dihydromorphine , halogeno-morphides, esters, ethers, and others have codeine, dihydrocodeine, and isocodeine analogues.
As an analgesic, codeine compares weakly to other opiates. Related to codeine in other ways are codoxime , thebacon , codeine-N-oxide genocodeine , related to the nitrogen morphine derivatives as is codeine methobromide, and heterocodeine , which is a drug six times stronger than morphine and 72 times stronger than codeine due to a small re-arrangement of the molecule, viz.
Drugs bearing resemblance to codeine in effects due to close structural relationship are variations on the methyl groups at the 3 position including ethylmorphine a. While having no narcotic effects of its own, the important opioid precursor thebaine differs from codeine only slightly in structure.
Pseudocodeine and some other similar alkaloids not currently used in medicine are found in trace amounts in opium as well. History[ edit ] Codeine, or 3-methylmorphine, is an alkaloid found in the opium poppy , Papaver somniferum var. Opium poppy has been cultivated and utilized throughout human history for a variety of medicinal analgesic, anti-tussive and anti-diarrheal and hypnotic properties linked to the diversity of its active components, which include morphine, codeine and papaverine.
Until the beginning of the 19th century, raw opium was used in diverse preparations known as laudanum see Thomas de Quincey 's Confessions of an English Opium-Eater , and paregoric elixirs , a number of which were popular in England since the beginning of the 18th century; the original preparation seems to have been elaborated in Leiden , the Netherlands around by a chemist named Lemort; in the London Pharmacopoeia mentions an Elixir Asthmaticum, replaced by the term Elixir Paregoricum "pain soother" in The progressive isolation of opium's several active components opened the path to improved selectivity and safety of the opiates-based pharmacopeia.
Codeine is the most widely used opiate in the world, [43] [44] and is one of the most commonly used drugs overall according to numerous reports by organizations including the World Health Organization and its League of Nations predecessor agency. It is one of the most effective orally administered opioid analgesics and has a wide safety margin. These products also contain other ingredients that can add to the risks. Two commonly misused cough and cold medicines are: Cough syrups and capsules containing dextromethorphan DXM.
These OTC cough medicines are safe for stopping coughs during a cold if you take them as directed. Taking more than the recommended amount can produce euphoria a relaxed pleasurable feeling but also dissociative effects like you are detached from your body. These prescription medications contain an opioid drug called codeine, which stops coughs, but when taken in higher doses produces a "buzz" or "high.
How Cough and Cold Medicines Are Misused Cough and cold medicines are usually sold in liquid syrup, capsule, or pill form. I feel panicky if I forget to put some in my purse. She lives with her parents and works hard to fund her studies, giving piano, maths and English lessons to children on the side. When the year-old events manager from Brighton began suffering from a bad back, that caused headaches and pain in his neck, he started taking codeine-based painkillers to allow him to carry on working.
Six months later, he's still taking them - despite the warning on the packets that they should not be taken for more than three days. The painkillers give me the peace of mind that I'll be able to do so. I'm at a crucial stage in building my career and savings so that I can eventually buy a house. I feel that it's not something I should have at my age. When she was 16, her mother, eager to end her daughter's constant stress headaches, brought home a packet of Syndol, an OTC painkiller containing paracetamol and codeine.
Most days, she would take two tablets - on bad days, it could be four or six. But neither she nor her parents realised there was anything wrong:
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