Duloxetine hydrochloride (Cymbalta - Lilly), a selective serotonin and norepinephrine reuptake inhibitor (SNRI) available for treatment of depression, has also been approved by the FDA for treatment of neuropathic pain associated with diabetic peripheral neuropathy (DPN). Duloxetine is one of two drugs approved specifically for management of neuropathic pain due to diabetes; the other, pregabalin (Lyrica - Pfizer), will be marketed soon and will be reviewed in the next issue of The Medical Letter.

The FDA has approved Basaglar (Lilly/Boehringer Ingelheim), a "follow-on" 100 units/mL insulin glargine product similar to Lantus (Sanofi), which recently went off patent. A 300 units/mL formulation of insulin glargine (Toujeo) was approved in 2015.

Sitagliptin phosphate (Januvia - Merck) is the first dipeptidyl-peptidase-4 (DPP-4) inhibitor to be marketed for treatment of type 2 diabetes. It has been approved by the FDA for oral use as monotherapy or in combination with metformin (Glucophage, and others), pioglitazone (Actos) or rosiglitazone (Avandia).

Exenatide injection (Byetta - Amylin/Lilly), a synthetic peptide that stimulates release of insulin from pancreatic beta cells, has been approved by the FDA as adjunctive therapy for patients with type 2 diabetes who have not achieved optimal glycemic control on metformin (Glucophage, and others), a sulfonylurea, such as glyburide (DiaBeta, and others), or both. Exenatide is not indicated for use with insulin.

Rosiglitazone, the second thiazolidinedione derivative to be marketed in the USA for treatment of type 2 diabetes, has been approved by the FDA for use either alone or combined with meformin.

Liraglutide (Victoza – Novo Nordisk), a glucagon-like peptide-1 (GLP-1) receptor agonist given by subcutaneous injection, has been approved by the FDA for treatment of patients with type 2 diabetes. It can be used alone or in addition to oral antidiabetic drugs such as metformin (Glucophage, and others) or glimepiride (Amaryl, and others). Liraglutide is not recommended for first-line therapy and is not approved for use with insulin.

Canagliflozin (kan" a gli floe' zin; Invokana – Janssen), a sodium-glucose co-transporter 2 (SGLT2) inhibitor, has been approved by the FDA for oral treatment of type 2 diabetes.

Miglitol, an oral alpha-glucosidase inhibitor similar to acarbase, is now available for treatment of type 2 diabetes.

Saxagliptin (Onglyza - Bristol-Myers Squibb), the second oral dipeptidyl peptidase-4 (DPP-4) inhibitor to be marketed in the US, has been approved by the FDA for treatment of adults with type 2 diabetes.

The FDA has approved Jentadueto XR (Boehringer Ingelheim/Lilly), a once-daily extended-release formulation of the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin and the biguanide metformin, for oral treatment of type 2 diabetes. Linagliptin and metformin have been available for years in a twice-daily immediate-release combination (Jentadueto). Once-daily extended-release formulations combining metformin with the DPP-4 inhibitors saxagliptin (Kombiglyze XR) and sitagliptin (Janumet XR) are also available.