PACE Case: Amputation Risk Averted

A 62-year-old female PACE participant has a past medical history of Type 2 diabetes (T2DM), heart failure, urinary incontinence, hypercholesterolemia, obesity, and lower limb amputation. The participant was recently enrolled in a PACE facility and her prescriber requested that a polypharmacy medication safety review be conducted to re-evaluate her medication regimen and reduce her MedWise Risk Score™, which was 19 out of 50 (moderate).

Based on her past medical history, the CareKinesis clinical pharmacist focused primarily on the following medications:

  • Canagliflozin 100 mg, daily
  • Linagliptin, 5 mg, daily
  • Humalog® Mix 75/25 KwikPen, 40 units subcutaneously QAM and 30 units QPM
  • Oxybutynin ER 5 mg, daily
  • Amlodipine-Benazepril 10 mg-20 mg, daily

Participant Assessment:
At the time of review, the CareKinesis pharmacist found that the participant’s blood sugar levels were inconsistent and trending high. The pharmacist noted that canagliflozin has a black box warning because it is associated with a two-fold increase in lower limb amputations, especially in patients with a history of cardiovascular disease. Given the participant’s past history of lower limb amputation, heart failure, and hypercholesterolemia, the CareKinesis pharmacist identified that canagliflozin may be an inappropriate medication to treat her T2DM. Her insulin regimen may also be suboptimal to control her Hemoglobin A1c (HbA1c) and changes may be needed.

Clinical Pharmacist Recommendation:

  • The CareKinesis pharmacist alerted the prescriber of the participant’s risk for lower limb amputation with canagliflozin, and recommended to re-evaluate benefit versus risk and consider discontinuation.
  • Prior to providing recommendations to re-evaluate the current insulin regimen, the CareKinesis pharmacist inquired if the participant has been adherent with her insulin regimen and a consistent diet and if she was using the proper technique for administration. As it was assessed that the participant has not been adherent to her insulin regimen, it was recommended to provide her and her caregiver with education and counseling to improve adherence. In an effort to further improve the participant’s adherence and optimize the current insulin regimen, the CareKinesis pharmacist also recommended a change to a basal insulin, such as insulin glargine, to provide peak-less coverage over 24 hours.
  • Additionally, the CareKinesis pharmacist mentioned that her overactive bladder may be resulting from her uncontrolled diabetes, which causes polyuria. If her diabetes management is optimized and her blood sugar levels improve, then a trial discontinuation of oxybutynin should be considered. This would also mitigate a potential competitive inhibition interaction. Since amlodipine has greater affinity to CYP3A4, with co-administration, oxybutynin concentrations may be greater than expected, further increasing risk of potential adverse drug events, including anticholinergic effects.

Prescriber Response and Outcome:
The prescriber agreed with the recommendations, and the following changes were made:

  • Canagliflozin 100 mg daily was discontinued.
  • Humalog Mix 75/25 Kwikpen was changed to insulin glargine (Basaglar) daily to provide basal coverage and improve adherence to the regimen.
  • Education was provided and the clinical team followed up closely with her for improved adherence to her medication regimen.
  • Since her blood sugars were better controlled, the Prescriber decided to trial discontinuation of oxybutynin ER 5 mg, daily.

With these changes, the participant’s MedWise Risk Score™ decreased to 12 out of 50, which is considered low risk, resulting in an estimated savings of $5,000 annually in medical costs.

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