What statement indicates that a client with CYP2D6 low polymorphism may not respond effectively to codeine?

The statement indicating that a client with a CYP2D6 low polymorphism may not respond effectively to codeine is one that expresses a lack of pain relief. In this case, the comment reflects that the medication "doesn't work for me, it does nothing for my pain," highlighting the individual's poor response to codeine.

Codeine is metabolized into its active form, morphine, by the enzyme CYP2D6. Variations in the CYP2D6 gene can affect enzyme activity, leading to differences in how individuals metabolize codeine. Those with low activity polymorphisms produce less or no active morphine from codeine, resulting in insufficient pain relief. Therefore, when a client states that codeine has no effect on their pain, it strongly suggests that their metabolism of the drug is impaired due to their genetic profile.

In contrast, statements reflecting quick onset of effects or prior efficacy do not indicate issues with drug metabolism and response. While one might report significant pain reduction or previous benefit from codeine, these do not specifically relate to current efficacy as affected by CYP2D6 polymorphism.