What is Codeine?
Codeine is a natural opiate derived from opium and also produced synthetically. It is effective as an analgesic, a cough suppressant and in treating diarrhea. It is used for the control of mild to moderate pain. It is commonly used in combined preparations, often with acetaminophen, aspirin or ibuprofen. More complex mixtures may be used in a number of proprietary cough syrups.
How does codeine work?
Codeine is metabolized to morphine in the liver through the activity of enzyme CYP2D6. The analgesic properties of codeine are derived from the morphine and codeine has no analgesic effect of itself. Codeine will not be effective in individuals lacking the CYP2D6 enzyme or who are taking any other drug which inhibits the action of this enzyme.
What does codeine look like?
Codeine is available in a large number of presentations, both alone and in combinations as well as in injectable form and in the form of a variety of cough syrups. Tablets are usually round, white and scored and are supplied in strengths of 15, 30 and 60 mg, with the respective strength in milligrams imprinted.
Codeine dosing and administration
The standard adult oral dosage of codeine is between 15 and 60 mg every four hours as needed for pain. No more than 260 mg should be taken in any 24 hours. Tolerance to codeine may develop relatively rapidly so that dosages above 60 mg are likely to give diminishing returns in terms of the level of pain relief compared to the increased incidence of adverse side effects. Codeine treatment should be tapered off gradually as abrupt cessation may lead to withdrawal symptoms.
Common adverse effects from codeine
The most common side effects of codeine are lethargy, lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, sweating and constipation. Other adverse effects may include allergic reactions, mood swings, abdominal pain and itching. More serious side effects which occur infrequently are hypotension, palpitations, syncope, anorexia, diarrhea, dry mouth, gastrointestinal problems, pancreatitis, anxiety, fatigue, headache, insomnia, agitation, vertigo and visual disturbances.
Codeine warnings and precautions
Extreme care must be taken if codeine is administered concurrently with any of the drugs listed in the next section as having possible interactions. Because codeine has strong potential for tolerance, dependence and abuse, it should never be taken in higher doses or for a longer period than prescribed. Withdrawal symptoms may occur if treatment is stopped abruptly. Codeine is intended for oral use only and abuse of this drug may cause overdose and death. This risk is increased if the drug is taken with alcohol or other narcotic drugs.
Interactions with codeine
Codeine may have dangerous interactions with other opioids, antihistamines, antipsychotics, anxiolytics and any other medication which acts on the central nervous system. These may include sedatives, hypnotics, anesthetics, emetics, tranquilizers and alcohol. The use of these together with codeine may result in dangerously suppressed respiration, profound sedation, coma and death. These combinations should therefore be used with caution. Other opioid analgesics should not be administered at the same time as codeine, Also to be avoided are anticholinergics, antidepressants, MAOIs and metabolic enzymes.