1, 2, 3, 4, and 5), naproxen, indomethacin, diclofenac, and others, as well as more complex mixtures, including such mixtures as aspirin + paracetamol + codeine ± caffeine ± antihistamines and other agents, such as those mentioned above. Codeine-only products can be obtained with a prescription as a time release tablet. 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. Injectable codeine is available for subcutaneous or intramuscular injection only; intravenous injection is contraindicated, as this can result in nonimmune mast-cell degranulation and resulting anaphylactoid reaction. Codeine suppositories are also marketed in some countries. Side effects
Common adverse effects associated with the use of codeine include drowsiness and constipation. Less common are itching, nausea, vomiting, dry mouth, miosis, orthostatic hypotension, urinary retention, euphoria, and dysphoria. Rare adverse effects include anaphylaxis, seizure, acute pancreatitis, and respiratory depression. As with all opiates, long-term effects can vary, but can include diminished libido, apathy, and memory loss. Some people may have allergic reactions to codeine, such as the swelling of skin and rashes.Tolerance to many of the effects of codeine, including its therapeutic effects, develops with prolonged use. This occurs at different rates for different effects, with tolerance to the constipation-inducing effects developing particularly slowly for instance. A potentially serious adverse drug reaction, as with other opioids, is respiratory depression. This depression is dose-related and is a mechanism for the potentially fatal consequences of overdose.
It is thus legal to possess codeine without a prescription, provided that it is compounded with at least one other active or inactive ingredient and that the dosage of each tablet, capsule, etc. does not exceed 100 mg or 2.5% concentration in the case of liquid preparations. The exemptions do not to apply to any preparation of codeine designed for injection. United States
In the United States, codeine is regulated by the Controlled Substances Act. Federal law dictates that codeine be a Schedule II controlled substance when used in products for pain-relief that contain codeine alone or more than 80 mg per dosage unit. Codeine without aspirin or acetaminophen (Tylenol) is very rarely available or prescribed in order to discourage abuse. Tablets of codeine in combination with aspirin or acetaminophen (paracetamol) and intended for pain relief are listed as Schedule II, requiring a physical paper-copy (aka triplicate) of the physician ordered prescription. Cough syrups are classed as Schedule III, IV or V, depending on formulation. For example, the acetaminophen/codeine antitussive liquid is a Schedule IV controlled substance.Some states have chosen to reclassify codeine preparations at a more restrictive schedule in order to lower the instances of its abuse. Minnesota, for instance, has chosen to reclassify Schedule V some codeine preparations (e.g. Cheratussin) as a Schedule II controlled substance.Schedule V Controlled Substances
Substances in this schedule have a low potential for abuse relative to substances listed in Schedule IV and consist primarily of preparations containing limited quantities of certain narcotics.