Meperidine is similar to morphine in many ways. However, with very high blood levels of meperidine – but not morphine – can be expected to cause which of the following? (AIPG 2011)
|B||Heightened response to pain|
|C||Intense biliary tract spasm|
|D||Psychosis-like state, possibly seizures|
a. High or frankly toxic serum levels of meperidine can cause seizures in addition to typical morphine-like effects including analgesia and ventilatory depression, or hypertension and a psychosis-like state.
b. It appears that administration of naloxone to combat excessive effects of meperidine may increase the risk of seizures. Meperidine causes less biliary tract spasm than morphine, so when bile duct disease is present and only short-term analgesia is indicated, meperidine may be preferred.
c. Because of the toxicity risk, meperidine should not be used for more than brief analgesic effects. The rather unique adverse effects attributed to meperidine are probably due to a major metabolite, normeperidine. A weak opioid analgesic, propoxyphene (structurally related to methadone), can produce similar toxic reactions. One of its metabolite, norpropoxyphene, is thought to be the cause.