Codeine
Codeine is a naturally occurring opioid derived from poppies. Codeine is a pro-drug of morphine, meaning that it is converted into morphine in the body. The morphine then binds to mu-opioid receptors found on the outsides of nerves in the brain and elsewhere. This stimulation of the neurones produces the effects of codeine. With continued use, however, the nervous system will get used to this stimulation and adapt its activity to account for the activation of mu-opioid receptors. If the codeine is removed, the nervous system then no longer functions normally on its own, leading to withdrawal symptoms.
Codeine is a powerful analgesic (painkiller) that provides feelings of euphoria, sedation and relaxation, and also side effects including nausea, dizziness and constipation. Different people react differently to codeine because of individual variation in the liver enzymes that convert codeine to morphine, and so some people may feel its effects for longer or more intensely than others. Codeine varies in strength, shop bought co-codamol that is mixed with paracetamol is between 5-8mg, but you can get codeine tablets up to 60mg.
Medically, codeine is used for the treatment of acute moderate pain due to its action as a pain killer; the short-term treatment of diarrhoea due to its constipation effects; and as a treatment for dry cough, due to its ability to suppress the cough reflex in the brain.
Codeine is a central nervous system (CNS) depressant. This means that it slows down fundamental physiological processes, including breathing and the heartbeat. Taking too much codeine can result in dangerous respiratory depression, meaning you stop breathing. This is more common with stronger, synthetic opioids, but it is also more likely to occur if you take codeine with other CNS depressants such as alcohol. IF you take too much co-codamol (codeine mixed with paracetamol), you could be at risk of liver damage from the paracetamol.
Like other opioids, you can become physically dependent on codeine. If you use codeine as recommended by a doctor, you are less likely to become physically dependent. However, continued recreational use or self-medicating with codeine could put you at greater risk.
Taking codeine daily for a prolonged period of time will likely cause physical and mental dependence and also have long-term effects on your body. It can cause constipation, reduced sex drive, muscle twitches and irregular periods. If you become dependent on codeine, you will most likely experience withdrawal symptoms when you come off the drug. These will be opposite to the effects of the drug, such as diarrhoea, sweating, agitation, sleeping difficulties, and shaking. Talk to a doctor if you are worried about addiction or stopping codeine consumption.
Avoid taking codeine in combination with alcohol or other depressants, due to the risk of respiratory depression. If you think someone is having an opioid overdose, immediate medical attention is required. Symptoms of overdose include slow, irregular or shallow breathing, pinpoint pupils, weak pulse, bluish lips and nails, and muscle spasms. Naloxone reverses opioid overdose by removing morphine from the mu-opioid receptor. If you use opioids, or spend time around people who do, you can get a naloxone nasal spray. You can order naloxone online, or get it for free from your local drug and alcohol support service, who will also train you on how to use it.
Codeine interacts with many other drugs, most dangerously with alcohol, other opioids, GHB, promethazine, and benzodiazepines like Valium. Combining codeine with other depressants could lead to excess drowsiness and, in extreme circumstances, respiratory failure and death. Combining with other opiates could increase withdrawal effects, which can be very serious. Codeine also causes constipation, and so other drugs that do the same, such as clozapine, could cause intestinal obstruction.
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