Showing posts with label codeine. Show all posts
Showing posts with label codeine. Show all posts

Sunday, October 17, 2010

Codeine Blues: End of the Line for an Opiate with Issues


Canada, UK consider phasing out the drug.

Among the many memorable anecdotes that have been uttered at the opening of an AA or NA meeting, surely one of the great ones is this: “I’m an addict, and a heroin junky. I went to the dentist today, and he sent me home with a prescription for Tylenol 3. And I thought: Do I really want to endanger my sobriety over a shitty buzz like codeine?”

Canada and the United Kingdom are ready to phase it out entirely. The U.S. Food and Drug Administration (FDA) issued a warning about it for nursing mothers as far back as 2007. Codeine, widely popular for its low euphoriant effects, and subsequent (if theoretical) decreased potential for abuse, may not be as strong as morphine and dilaudid, but it is perhaps the most commonly prescribed opiate in the world—and it comes with a major flaw. Unlike other opiates, codeine is very unpredictable in its interactions with an enzyme called CYP2D6. This enzyme is a primary workhorse in the body’s process of breaking down and excreting many different drugs. Poor metabolizers produce less of this crucial enzyme, which means that drugs are broken down and excreted at a much slower pace (See my earlier post ).

 Specifically, as two physicians recently wrote in the Canadian Medical Association Journal (PDF),
“polymorphisms occur in the cytochrome P450 isoenzyme CYP2D6 that enhance codeine metabolism to morphine.” In 2007, following the death of an infant nursed by a codeine-using mother, the FDA “warned nursing mothers that if they took codeine after childbirth, their newborns might be at risk for a morphine overdose,” according to a New York Times report.

Alternatively, other metabolizers may have little or no reaction to codeine-based medications. Drugs of abuse severely complicate these enzymatic issues, since addicts and alcoholics are not known for volunteering information about their condition to medical or hospital personnel.

Testing for the enzyme is possible, but not likely to catch on with cash-strapped medical and dental centers. Dr. Noni MacDonald at the University of Halifax and Dr. Stuart MacLeod at the University of British Columbia argue in the CMAJ that 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.” The younger the user, the more susceptible he or she will be to these effects, “possibly because of age-related maturation differences in the blood-brain barrier.” The authors warned that serious side effects “including life-threatening respiratory depression,” have also been reported in adults.

The ultrafast metabolizing variant of CYP2D6 is not evenly distributed throughout the world’s population. The number of people in danger of experiencing high morphine levels after codeine use range from 40% in North Africa to 3% in Europe, the authors say. Rates in the U.S. are 8%, meaning roughly one in ten Americans risk an adverse reaction when taking codeine.

Since the groups at highest risk are infants and children, nations have taken various steps to mitigate the risk. “Switzerland sets the minimum age for codeine-based treatment at 1- years, the Netherlands at 1 year, the United States at 3 years and Canada at 2 years.”

Despite these controls, the authors strongly argue for “a more direct approach,” calling for doctors to “stop using the prodrug codeine altogether and instead use its active metabolite, morphine. Not only is the metabolism of morphine more predictable that that of codeine, but also it’s cheaper.” So codeine is just not consistently good at what it does. Problem is, an opiate doesn’t have to be good to be great, as innumerable codeine addicts can attest.

The argument in Canada made sense to Britain’s watchdog agency for medicines, the Medicines and Healthcare products Regulatory Agency (MHRA). According to a report in The Independent by science editor Steve Connor, the MHRA “wrote to medical authorities in the UK warning that its experts have advised that all over-the-counter liquid cough medicines containing codeine should no longer be used in children under the age of 18,” and that “the risks of [over-the-counter] cough medicines for children containing codeine outweigh the possible benefits.”

Codeine is typically offered in paired form, with either acetaminophen or aspirin, as protection against opiate abuse. In theory, a drug abuser would be likely to trigger a Tylenol overdose before reaching an opiate overdose on codeine pills. However, it is perfectly possible to maintain an active opiate addiction on prescription Tylenol 3s, Fiorinal, or Phenergan cough syrup, among other drugs.

And finally, I would not be revealing any great secrets by suggesting that the extraction of codeine from a codeine-acetaminophen tablet through basic solubility and filtration procedures may not be something one needs to be a chemistry major to pull off. 

The OTC medicine industry in the UK views all of this as a tired argument. A spokesperson for Britain’s Proprietary Association, which represents over-the-counter manufacturers, said: "There has already been a long-drawn-out discussion of codeine. If its value as a pain reliever had not outweighed the risks then it would have been withdrawn and the point is that codeine still has a value as a pain reliever.”


Sunday, July 5, 2009

Common Medicines That Can Kill You [Guest Post]


Legal but lethal.

[Today’s post was written by Kat Sanders, who regularly blogs on the topic of pharmacy technician certification. She welcomes your comments and questions at her email address: katsanders25@gmail.com.]

Medicines are supposed to save lives, but as with all things that are not used responsibly, they end up killing people more often than not when they are abused. It’s not just illegal drugs that kill; even the ones that are prescribed have the potential to become dangerous when they are not used as they are supposed to be. While we know that heroin, crack and other illegal substances cause death in the event of an overdose, we are not aware of many others that are relatively unknown, but just as dangerous. The below list is not exhaustive but details just a few of the drugs that could lead to death if abused.

NPF: Non-Pharmaceutical Fentanyl has been responsible for more than 1000 deaths (those that have been reported--there are definitely going to be many more that went unnoticed or unreported) between 2005 and 2007, according to the US Center for Disease Control and Prevention (CDC). NPF is a painkiller, one that is also illegally produced and sold because of its narcotic effects. Since it is much cheaper than heroin, sales are high, as are the deaths that it is responsible for. What people do not realize is that when this drug is produced illegally, it is 30 to 50 times more potent and risky than heroin.

Codeine: We would hardly think that the cough syrups we obtain over the counter could end up killing us, but the codeine they contain is a narcotic that causes hallucinations if taken in large amounts. And when cough syrups are abused, they could end up being potentially dangerous, like the case of Chad Butler, the rapper more popularly known as Pimp C. The singer already suffered from sleep apnea, and large amounts of codeine combined with sleep apnea is apparently enough to cause respiratory problems and cause death.

Acetaminophen (Paracetamol): While paracetamol alone cannot cause death, if you are a habitual drinker, your liver is already weak and damaged. And when you take large doses of paracetamol under such conditions, you may start feeling the symptoms in a day or two; you may experience a stomach ache, vomit, and feel pretty ill. Death, if it occurs, happens after four or five days after the overdose, if you do not take any treatment at all in the interim.

Opioid painkillers and Anti-depressants: This combination was responsible for killing up and coming actor Heath Ledger. The star, who was said to be increasingly despondent and depressed, was on anti-anxiety drugs and painkillers as part of his prescription. An overdose (a combination of six different drugs that included sedatives and painkillers) found him dead, just before the release of the blockbuster movie The Dark Knight, the latest in the Batman series and the one that saw him winning a posthumous Oscar for his devilish portrayal of the Joker.
The CDC reports that accidental drug overdoses are responsible for the death of more than 22,000 Americans every year. In fact, it is the second leading cause of preventable deaths, next to automobile accidents. And this is why we need to be extra careful and exercise caution when handling drugs and medicines.

Photo Credit: Canwest News Service

Related Posts Plugin for WordPress, Blogger...