Demerol
Meaning of Demerol: A drug displaced by its own breakdown product, which relieves no pain, lingers longer than the parent drug, and irritates the nervous system.
Definition of Demerol
Demerol is a brand name for meperidine, an opioid painkiller once used widely for moderate to severe pain. Like other opioids it binds receptors in the brain and spinal cord and blunts the perception of pain. Its use has narrowed considerably, largely because the body converts it into a long lasting breakdown product with no pain relieving effect of its own.
What is normeperidine and why does it matter?
It is what remains after the liver has worked on meperidine. Normeperidine does not relieve pain, but it does act on the nervous system, and its effect is excitatory rather than sedating: tremor, twitching, agitation and, at high enough levels, seizures. Two things make it awkward. It hangs about far longer than the parent drug, so it accumulates when doses are repeated, and it is cleared by the kidney, so it builds up faster in anyone whose kidneys are working poorly. Nothing about the pain relief warns that this is happening, and the standard antidote for opioid overdose reverses the parent drug without touching the metabolite.
How does it compare with other opioids?
| Feature | Meperidine | Most other strong opioids |
|---|---|---|
| Duration of relief | Short, often a few hours | Comparable or longer, with long acting forms available |
| Active metabolite | Builds up and irritates the nervous system | Metabolites usually inactive or still pain relieving |
| Use for lasting pain | Poorly suited, since repeat dosing is the problem | Routinely used when an opioid is indicated |
An older belief held that meperidine was gentler on the muscular ring at the outlet of the bile duct, and was therefore better for pain from gallstones or the pancreas. Comparative work has not supported the claim, and it is no longer treated as a reason to choose the drug.
Where does it still appear?
In short, single dose situations, where accumulation has no time to occur: pain during a brief procedure, or immediately after one. It also has a distinct and useful effect on the violent shivering that can follow anesthesia, which it suppresses more reliably than other opioids do. Against that sit its interactions. Combined with drugs that raise serotonin levels, particularly the older class of antidepressants known as monoamine oxidase inhibitors, meperidine can provoke a dangerous reaction of fever, rigidity and confusion that other opioids are far less likely to cause.
Also known as
Used in a sentence
Demerol was given for short-term pain relief following the procedure.
Good to know
The breakdown product of meperidine relieves no pain, lasts longer than the drug itself and accumulates with repeated doses or reduced kidney function, which is the main reason the drug is little used for sustained pain control.