New research asserts that methylnaltrexone appears to extend survival in people receiving opioid for advanced cancer pain. Methylnaltrexone is approved for the treated of opioid-related constipation.
Evidence indicated that treated cancer pain with opioids can actually shorten people’s lives.
Mthylnaltrexone blocks the receptor that is involved in the progression of tumors without diminishing the painkilling power of opiates. Therefore the apparent survival benefit makes sense.
A retrospective analysis of two clinical trials of patient with advanced cancer who were being treated with opioids lived 20 days longer if they received methylnaltrexone instead of a placebo.
The study is the result of a research project that started in 1979 but took a drastic turn when a pharmacologist tried to help a friend that was constipated from the morphine being used to treat his cancer pain.
In an effort to find a molecule that would stop the constipating effect of opioids by blocking their receptors in the gut but would also preserve the analgesic effect, a morphine-blocking drug was established.
Methylnaltrexone appears to provide relief for patients who have not been helped by conventional laxatives.
The reason why some patients don’t respond is unclear, but genes could play a role. When the drug works, it works very fast.
The patients did suffer from some adverse effects such as cramping, but almost all of the patients wanted more of the drug because it was so relieving to them.
The study found that opioids appear to enhance the blood supply around tumors and enhance their growth. Other studies have reinforced the link between opioid use and cancer progression.
However researchers acknowledge that some other studies had failed to find a link between opioid use and cancer progression. Clinicians should wait for further evidence.