Morphine is metabolized in the liver to morphine-6-glucuronide and morphine-3-glucuronide, both of which are excreted by the kidneys. In the setting of renal failure, these metabolites can accumulate, resulting in a lowering of the seizure threshold. Morphine should therefore be used with caution with mild renal impairment and be avoided in the setting of renal failure.
they gave a hint of increased creatinine level, plus older age can give a slowed down metabolism and CNS symptoms
can someone explain how morphine is degraded into active metabolites that accumulate? I couldn't find any sources that state this fact. Isn't it metabolized through the P450 system and excreted in urine?