A 55-year-old Caucasian woman was diagnosed with type 2 DM 15 years prior to presentation. Her DM remained uncontrolled with fasting blood glucose (BG) values ranging between 300 mg/dl and 400 mg/dl, and as high as 500 mg/dl in the recent past as measured by her Ascensia  Contour  which reports plasma values. Her most recent hemoglobin A1C (A1C) was 8.0% and previously was 8.4%. Antidiabetic medications included metformin 500 mg TID, glimepiride 4 mg BID, and NovoLog  70/30 Mix FlexPen 50 units BID. The patient reported adherence to all drug therapies, no previous hypoglycemic symptoms or episodes, and received diet counseling at most appointments. Other medical conditions and medications included the following: obesity (body mass index [BMI] 40.3, 110 kg) treated with diet and exercise, insomnia treated with zolpidem 10 mg qHS prn, depression treated with bupropion XL 300 mg daily and alprazolam 0.5 mg TID, hypertension treated with valsartan/hydrocholorthiazide 160/25 mg daily, dyslipidemia treated with rosuvastatin 10 mg daily, and heartburn treated with lansoprazole 30 mg daily.
Due to continued elevated BG values, sitagliptin was added to her current therapy; no other medication alterations were made at this time. As the patient's creatinine clearance (CrCl) was normal (serum creatinine [SCr] 0.7 to 0.8 mg/dl) sitagliptin was dosed at 100 mg daily, which she administered at 6 AM. At the patient's visit, 10 days later, she reported fasting, lunch-time, and afternoon BG values of 200 mg/dl, 100 mg/dl, and 200 mg/dl, respectively. She was particularly concerned about several low values around 50 mg/dl that consistently occurred at 10 AM with symptoms of diaphoresis, tachycardia, and ataxia. In response, glimepiride was discontinued, and her insulin was slowly self-titrated downward to 36 units BID. All other medications and doses were maintained. Two months following sitagliptin initiation her A1C had decreased to 6.7% and her morning BG values ranged between 108 and 130 mg/dl while evening values were always less than 170 mg/ dl. Periodically BG levels nadired in the upper 60s mg/dl with minimal hypoglycemic symptoms.
Approximately one year after sitagliptin initiation, the patient's Medicare Part D plan required a prior authorization (PA). The patient was unable to pay full price for sitagliptin and was without the medication for three days. During this time all other medication doses remained the same and she experienced no symptoms of hypoglycemia or documented BG less than 70 mg/dl. While the insurance provider was contacted the patient was provided with samples of sitagliptin and again mild hypoglycemic events immediately presented.
The PA was submitted with proof of efficacy (decline in A1C) and other medications previously and currently used. The PA was promptly rejected and an appeal was denied. During a follow-up phone conversation, a representative from the Medicare Part D provider explained sitagliptin would continue to be rejected because of the off-label combination with insulin regardless of the patient's disease state improvements. The clinician plans to provide the patient with sitagliptin samples until she is able to switch Medicare Part D plans in hopes of regaining sitagliptin coverage.