Full Clinical Explanation of Lillian’s Medication Risk

Lillian recently enrolled in PACE. Although Lillian is only taking 6 medications, she is still at high risk due to multi-drug interactions (Medication Risk Score = 27). She is likely to experience preventable medication-related problems. Lillian’s CareKinesis pharmacists and PACE doctors sought to re-evaluate her medications, optimize her therapy, and reduce her medication risk.

Lillian’s Medication List:

  • Tolterodine
  • Fluvoxamine
  • Gabapentin
  • Hydrocodone/Acetaminophen
  • Amlodipine
  • Rosuvastatin

1. Competing medications
Lillian is prescribed hydrocodone PRN and fluvoxamine QD, both of which are metabolized by CYP2D6. Fluvoxamine demonstrates a greater affinity for CYP2D6, preventing the activation of hydrocodone into its active metabolite, hydromorphone. We expect this interaction to result in inadequate pain relief from the hydrocodone doses administered concurrently with fluvoxamine. Evaluate Lillian’s pain and consider alternative therapy for pain management.

Fluvoxamine is an inhibitor of CYP2C9, the metabolizing pathway of rosuvastatin. Administration of these two agents may result in significantly increased concentrations of rosuvastatin, which may contribute to muscle pain and other adverse events. Using duloxetine will eliminate this interaction, but like fluvoxamine, may be problematic for co-administered hydrocodone doses.

2. Anticholinergic burden
Tolterodine has an anticholinergic burden of 3/3. Highly anticholinergic medications contribute to falls and other adverse effects, such as cognitive impairment, constipation, and dry mucous membranes. Consider a trial discontinuation to assess Lillian’s response to the medication by assessing the number of urges/voids. If minimal, evaluate benefits and risks prior to restarting therapy.

3. Sedative burden
Lillian was prescribed gabapentin 100mg TID for neuropathy and anxiety. Subtherapeutic doses of gabapentin may not be providing adequate pain relief. In an effort to reduce Lillian’s overall sedative burden (her score = 10), polypharmacy, and mitigate multi-drug interactions, consider discontinuing gabapentin and fluvoxamine and initiating duloxetine monotherapy. Duloxetine, an SNRI, has proven effective for the treatment of neuropathy, depression, and anxiety. It has a sedative burden score of 2 and may reduce the need for additional therapies.