Knowing that the elderly are more prone to slower metabolism (along with unknown poor metabolism genotypes), they experience far more ADRs, adverse drug reactions, than the non-elderly. Most of the FDA warnings/contraindications for medications and gene-drug interactions are for when the patient is a genetic poor metabolizer for one of the involved CYPs (P450s), AND the drug of interest inhibits the involved CYP enzyme, thus raising the plasma levels of the drug. It's a double whammy. In the case of Kava, at least in vitro, it is known to inhibit many of the P450s involved in drug metabolism. Not knowing the patient's P450 genotype status, and not knowing what current medications she is on, along with introducing Kava could be dangerous for possible ADRs occurring. These ADRs would be whatever side effects are listed in the PIs of the drugs she is currently taking. Hope this helps.