dcb asked
I was reading about the metabolizing enzyme CYP2D6. It said Prozac is a strong inhibitor, with an 80% decrease in clearance. Could this be why Norco (hydrocodone/acetaminophen) side effects seem to last 2-3 days? Such as dizziness, clumsiness, etc
Answer
There is a minor interaction between Prozac (fluoxetine) and hydrocodone and caution is advised when using both together. In some cases, Prozac can decrease the overall effect of hydrocodone. However, this interaction doesn't necessarily preclude the use of both together.
Prozac is an inhibitor of the metabolizing enzyme CYP2D6 in the liver. This means that Prozac lessens the activity of this enzyme.
Hydrocodone, while active in it's own right, is metabolized in the body to multiple metabolites including norhydrocodone and hydromorphone. Hydromorphone is more potent than hydrocodone and is responsible for the majority of the analgesic activity. Theoretically, inhibition of CYP2D6 will decrease the metabolism of hydrocodone, decreasing conversion to hydromorphone, leading to an overall lessened effect from the medication.
While the interaction exists between Prozac and hydrocodone, it doesn't appear to make a significant clinical difference in most patients. If you are having lessened effects from your hydrococone prescription and are on Prozac, the interaction could be one reason why.
Conversely, if you are particularly sensitive to the effects of hydrocodone (the parent compound), the decrease in metabolism due to the Prozac interaction could potentially make it last longer in the body. Generally though, any side effect experienced from the medication should not last more than one day.
