TABLE
| GLP-1 | DPP-4 | |||
|---|---|---|---|---|
| Exenatide1 | Liraglutide2 | Sitagliptin3 | Saxagliptin4 | |
| Route | Subcutaneous | Subcutaneous | Oral | Oral |
| Frequency | Twice daily | Once daily | Once daily | Once daily |
| Relation to meals | Within 60 min prior to eating | With/without food | With/without food | With/without food |
| Timing | Before the 2 main daily meals, ≥6 h apart | Any time of day | Any time of day | Any time of day |
| Dosing, initial | 5 μg BID; increase to 10 μg BID after 1 mo if needed for glucose control | 0.6 mg OD x 1 week, then 1.2 mg OD; increase to 1.8 mg OD if needed for glucose control | 100 mg OD | 2.5 mg or 5 mg OD |
| Dosing, renal disease | Do not use if CrCl <30 mL/min or in ESRD; use with caution in patient with renal transplantation | No adjustment; use with caution | CrCl ≥30 to <50 mL/min, 50 mg OD; CrCl <30 mL/min or ESRD requiring dialysis, 25 mg OD | CrCl ≤50 mL/min or ESRD requiring hemo-dialysis, 2.5 mg OD |
| BID, twice daily; CrCl, creatinine clearance; ESRD, end-stage renal disease; OD, once daily. | ||||
Case 1
During your discussion with this building contractor, you begin to talk about the GLP-1 agonists and DPP-4 inhibitors as treatment options. You begin to discuss the need to self-inject the GLP-1 agonist, when he interrupts you and tells you that he does not want to hear anything about insulin or other medications that would require him to self-inject, because his work environment and schedule would make this impossible.
While his feelings are understandable, open communication with this patient can do much to allay his concerns. Although concerns about injecting outside the home are common with insulin, the need for this with a GLP-1 agonist is unlikely because of the twice-daily exenatide and once-daily liraglutide dosing schedules and the lack of need to intensely monitor blood glucose levels. However, if the patient eats breakfast at work or doesn’t eat breakfast at all, this may become an issue with exenatide because of the need to eat within 60 minutes of taking a dose.
Concerns about self-injecting also can be addressed by showing patients the pen injection device and its small-gauge needle and instructing them in its use. Having a patient self-inject the first dose in the office can relieve much anxiety. Patients often comment about how easy and painless it is to inject themselves. One caution, however, is that if a patient self-injects a dose of exenatide in the office, he or she must be reminded of the need to eat within the next hour.
Talking about risks
Case 3
During your discussion with this 68-year-old woman about modifying her therapy, you include the GLP-1 agonists and DPP-4 inhibitors as treatment options. She replies, “Yes, I’ve seen information about them at my job at the library. They can cause cancer, can’t they?”
This comment highlights the importance of talking openly with patients to help them make good decisions about their health. Discussions often focus on the anticipated benefits of medications, but as we know, there are risks associated with every medication choice. Initially discussing risks with this patient could avoid having her return to the office angry with you for not warning her before she began taking the medication.
In this situation, as part of your discussion about liraglutide, you could refer her to the manufacturer’s Web site for information about the Risk Evaluation and Mitigation Strategy (REMS) program for liraglutide, sitagliptin, and saxagliptin. You also could provide her with the patient medication guide included with the program. REMS programs have been implemented for several glucose-lowering medications, since implementation of the REMS program by the US Food and Drug Administration (FDA) in 2007; these include exenatide, liraglutide, pioglitazone with or without glimepiride, rosiglitazone with or without glimepiride, and sitagliptin with or without metformin. Medication guides and other information are available online from the FDA at http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm111350.htm.
Medication cost
Case 3
You continue your discussion with this 68-year-old part-time librarian about the benefits and risks of insulin, a thiazolidinedione, and a glinide, as well as a GLP-1 agonist and a DPP-4 inhibitor. Suddenly she asks you how much these medications cost.
The cost of health care in general and medications in particular continue to dominate discussions. This is especially true for medications that have arrived on the market more recently, including the GLP-1 agonists and the DPP-4 inhibitors, which range in cost from about $7 to $14 per day.9-12 These agents, however, may be covered by health insurance, so cost to the patient may be limited to copays. The lower risk of hypoglycemia observed with the GLP-1 agonists and DPP-4 inhibitors compared with some other glucose-lowering therapies may make it possible to perform self-monitoring of blood glucose less frequently, but this is an individual patient issue.