Doris Obinna
Following the Federal Government’s ban of cough syrups with codeine content, in reaction to widespread addiction, the searchlight has beamed on codeine, easily one of the world’s most common painkillers. The question on most people’s lips is this: Is codeine a curse or blessing?
Studies have show that codeine may be unsafe, ineffective and potentially addictive when taken regularly.
Growing concern about codeine, which has been used as a painkiller for about 200 years, has emerged from recent DNA studies showing that people with different genetic make-ups respond differently to the opioid drug, which is inactive until it is broken down inside the body into highly addictive morphine.
The variability of people’s response to painkillers containing codeine, combined with its potentially addictive nature when taken regularly, led Professor Noni MacDonald of Dalhousie University in Halifax, Nova Scotia, and Professor Stuart MacLeod of the University of British Columbia, in Vancouver, to ask whether the time has come to phase out the drug completely.
In an explosive editorial published in the journal of the Canadian Medical Association, MacDonald and MacLeod said the public perception of codeine as a safe drug was fostered by its widespread availability in many over-the-counter painkillers, sold in Britain as well-known brands such as Nurofen Plus, Solpadine Max and Panadol Ultra as well as generic products.
According to them, “however, recent advances in our understanding of pharmacogenetics raise serious concerns about the safety of codeine, including emerging evidence that the narcotic can cause death even at conventional doses. Has the time come to phase out codeine altogether?”
Scientists have already identified some genetic factors that significantly affect the rate at which codeine is broken down into morphine by the liver. These genetic factors vary within the general population, making the response to codeine highly unpredictable from one person to the next, MacDonald and MacLeod said.
“All of these genetic variations can have potentially serious clinical consequences. The wrong combination can result in toxic levels of morphine, even at conventional doses of codeine. For infants and young children in particular, this can be deadly because age appears to be a key factor in susceptibility to adverse effects of morphine,” they said.
A Lagos doctor, Sunday Olalekan, sees codeine as a narcotic. According to him, it is used for treating pain and suppressing cough, adding: “It should not be used when nursing or for children under age 12.”
He said codeine, “by itself, is categorised as a Class II controlled drug, like morphine,” adding: “Combined with other drugs it is Class III (tablet) or Class V (liquid). Like all opioids there are risks of dependence and addiction.”
Olalekan said: “More serious adverse effects include severe low blood pressure, adrenal insufficiency and accidental ingestion.”
The doctor said since codeine was a narcotic “it has a potential for abuse. Therefore, patients with current or previous drug addiction problems should be monitored closely for addiction. Dependence and addiction can occur with codeine, even at prescribed dosages when taken over long periods. Misuse of codeine can lead to serious cardiac arrest and sudden death. It is important to be aware of drug interactions, effects on pregnancy and nursing mothers, as well as common side effects on the user.”
On the safety of codeine, he said: “As far as advantages go, codeine has a pretty decent safety profile. Also, you can use it as an antitussive as well as an analgesic. It does come in many doses and dosage forms. It is now the most potent opiate that is not a C2. This means it can be prescribed electronically as well as the other means.”
Codeine and how it works (mechanism of action)
Codeine is a narcotic pain-reliever and cough suppressant similar to morphine and hydrocodone. 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.
Codeine increases tolerance to pain and decreasing discomfort. However, the pain will still be apparent to the patient. In addition to reducing pain, codeine also causes sedation drowsiness and depresses breathing. Codeine frequently is combined with acetaminophen (Tylenol) or aspirin for more effective pain relief.
Codeine is habit forming (addictive). Mental and physical dependence can occur but are unlikely when used for short-term pain relief. Using codeine during pregnancy can cause opioid withdrawal syndrome in the newborn, which may be life-threatening.
Yes, you need a prescription for codeine. In US, it is a schedule II controlled substance.
Side effects of codeine
The most frequent side effects of codeine include: Lightheadedness, dizziness, nausea, vomiting, short of breath, sedation, allergic reactions, constipation, abdominal pain, rash and itching
There is also life-threatening respiratory depression, severe low blood pressure and adrenal insufficiency.
The dosage
The usual adult dose of codeine for pain is 15-60 mg every 4-6 hours as needed. The dose for cough is 10 to 20 mg every 4-6 hours as needed. The maximum dose for treating cough is 120 mg every 24 hours.
Benefit of codeine
Opioids remain good treatment for acute pain and cancer pain syndromes. Indeed, “recent studies of physicians specialising in pain, as well as those who do not, have shown that prescription of long-term opioids is increasingly common,” said a report.
According to a report by John Hopkins Medicine, as reported in hopkinsartritiscenter.org, “several controlled trials have documented the effectiveness of opioids in the treatment of chronic non-malignant pain such as low back pain, post-herpetic neuralgia, and painful peripheral neuropathy. These studies support the use of opioids to provide direct analgesic actions and not just to counteract the unpleasantness of pain. In the treatment of chronic low back pain, transdermal fentanyl significantly decreased pain and improved functional disability.
“In a randomised, double-blind, placebo controlled trial, controlled-release oral opioids were more effective than tricyclic antidepressants in decreasing the pain of post-herpetic neuralgia. Other studies have documented the presence of opioid receptors in the peripheral tissues activated by inflammation. These findings suggest a role for opioids in the treatment of chronic inflammatory diseases such as rheumatoid arthritis and connective tissue disorders.
“The use of opioids for the treatment of non-inflammatory musculoskeletal conditions is more confusing. A randomised double-blind, placebo-controlled crossover study of oral controlled release morphine was performed in patients with chronic regional, soft tissue musculosketal pain conditions that were resistant to codeine, anti-inflammatory agents and anti-depressants. Although patients experienced a decrease in pain, they did not experience significant psychological or functional improvement. In contrast, another randomised, placebo-controlled clinical trial in patients with chronic non-malignant pain found that treatment with controlled-release codeine reduced pain as well as pain-related disability.”