How potent is meperidine compared to morphine?

Meperidine, also known as pethidine, is an opioid analgesic that is considered to be less potent than morphine. Specifically, meperidine has a potency that is roughly about one-tenth that of morphine. This means that, in terms of pain relief, it would take approximately 10 milligrams of meperidine to achieve the same level of analgesia that can be achieved with 1 milligram of morphine.

The use of meperidine has declined in clinical practice due to its side effects and relatively short duration of action compared to morphine. In addition, the fact that it can cause toxic metabolites, particularly normeperidine, which can lead to seizures when accumulated, has made clinicians wary of its use. Overall, understanding the potency difference is crucial for safe and effective pain management in patients, ensuring that dosages are administered accurately to achieve desired therapeutic effects while minimizing risks.