Differences and similarities of morphine and oxycodone.

This review summarises the current knowledge of the effects of morphine and oxycodone. The analgesic effect is estimated to be equal. However, the relative potency of oxycodone is variably higher which increases the risk of over- and underdosing. The time to onset of analgesia following intravenous or oral administration of oxycodone is shorter than the one of morphine. This, among other factors, may lead to a higher risk of addictive behaviour.