Codeine is a member of the opioid family of drugs that is derived from the opium poppy and synthesized in a laboratory to create an analgesic drug that is common prescribed for the treatment of mild to moderate pain, cough and sometimes diarrhea.
Codeine is the second-most predominant alkaloid in opium, at up to three percent. Although codeine can be extracted from natural sources, a semi-synthetic process is the primary source of codeine for pharmaceutical use. It is considered the prototype of the weak to midrange opioids (tramadol, dextropropoxyphene, dihydrocodeine, hydrocodone, oxycodone). Codeine-only products can be obtained with a prescription as a time release tablet (e.g., Codeine Contin 100 mg and Perduretas 50 mg). Codeine is also marketed in cough syrups with zero to a half-dozen other active ingredients, and a linctus (e.g., Paveral) for all of the uses for which codeine is indicated. Codeine or 3-methylmorphine (a naturally occurring methylated morphine) is an opiate used to treat pain, as a cough medicine, and for diarrhea. Codeine-only products can be obtained with a prescription as a time release tablet (e.g., Codeine Contin 100 mg and Perduretas 50 mg). Codeine is also marketed in cough syrups with zero to a half-dozen other active ingredients, and a linctus (e.g., Paveral) for all of the uses for which codeine is indicated. Codeine phosphate is an opioid analgesic (pain reliever) drug used to treat many causes of mild to moderate pain. Codeine phosphate is available in a generic form termed codeine. Common side effects of codeine phosphate include drowsiness, lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, stomach pain, sweating, constipation, itching, or rash. Codeine phosphate may be habit-forming.  Codeine is an opiate whose active ingredient is found in many different medications that treat pain, cough, and diarrhea. Brand names of drugs containing codeine for pain relief include Tylenol #3, Tylenol #4, Soma Compound with Codeine, Fiorinal with Codeine, Fioricet with Codeine, and Capital and Codeine. Codeine works by blocking responses to pain, suppressing your cough reflex, and causing drowsiness. Like all drugs related to or derived from opium, codeine is a narcotic (also known as an opiate) and is a controlled substance. The Drug Enforcement Administration (DEA) classifies codeine as a Schedule II or III controlled substance. However, low doses of codeine are still sold over-the-counter (OTC) in some states. Brand names of drugs containing codeine for pain relief include Tylenol #3, Tylenol #4, Soma Compound with Codeine, Fiorinal with Codeine, Fioricet with Codeine, and Capital and Codeine. Codeine works by blocking responses to pain, suppressing your cough reflex, and causing drowsiness. BRAND NAMES: none. DRUG CLASS AND MECHANISM: Codeine is a narcotic pain-reliever and cough suppressant similar to morphine and hydrocodone. Moreover, a small amount of codeine is converted to morphine in the body. The precise mechanism of action of codeine is not known; however, like morphine, codeine binds to receptors in the brain (opioid receptors) that are important for transmitting the sensation of pain throughout the body and brain. Tablets of codeine in combination with aspirin or paracetamol (paracetamol /Tylenol) made for pain relief are listed as Schedule III; and cough syrups are Schedule III or V, depending on formula. The paracetamol/codeine pain-relief elixir (trade name Tylenol Elixir with Codeine) is a Schedule IV controlled substance. Codeine-only products can be obtained with a prescription as a time release tablet (e.g., Codeine Contin 100 mg and Perduretas 50 mg). Codeine is also marketed in cough syrups with zero to a half-dozen other active ingredients, and a linctus (e.g., Paveral) for all of the uses for which codeine is indicated. The drug is habit-forming when taken repeatedly and sustained use of codeine can lead to a number of physical and psychological dependence factors that are difficult to treat. Codeine can be a dangerous substance if it is not taken exactly as prescribed or if the drug is taken with other medications or alcohol. Codeine and alcohol can have deadly side effects because both of these substances cause central nervous system depression that can lead to come, seizures, and death. Talk to your doctor if you are a regular drinker and you have been prescribed codeine for the treatment of cough or pain. Codeine is a member of the opioid family of drugs that is derived from the opium poppy and synthesized in a laboratory to create an analgesic drug that is common prescribed for the treatment of mild to moderate pain, cough and sometimes diarrhea. Codeine and alcohol can have deadly side effects because both of these substances cause central nervous system depression that can lead to come, seizures, and death. Talk to your doctor if you are a regular drinker and you have been prescribed codeine for the treatment of cough or pain. Uses of This Medicine. Codeine is used to relieve mild to moderately severe pain. It belongs to the group of medicines called narcotic analgesics (pain medicines). This medicine acts on the central nervous system (CNS) to relieve pain. When codeine is used for a long time, it may become habit-forming, causing mental or physical dependence. 
https://en.wikipedia.org/wiki/Codeine https://en.wikipedia.org/wiki/Codeine http://www.rxlist.com/codeine-phosphate-side-effects-drug-center.htm http://www.everydayhealth.com/drugs/codeine http://www.everydayhealth.com/drugs/codeine http://www.medicinenet.com/codeine/article.htm https://en.wikipedia.org/wiki/Codeine http://www.codeine.com/about/what-is-codeine.html http://www.codeine.com/about/what-is-codeine.html http://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0009704/?report=details
what is codeine