The thiazolidinediones rosiglitazone (Avandia) and pioglitazone (Actos) are peripheral insulin sensitizing agents used to treat hyperglycemia in patients with type 2 diabetes; one or the other is often used as a second or third agent with metformin (Glucophage, and others) and/or a sulfonylurea such as glimepiride (Amaryl, and others). A recent report suggested that rosiglitazone may increase the incidence of myocardial infarction (MI) and cardiovascular mortality.

A reader has questioned why the label for the COX-2 selective NSAID celecoxib (Celebrex, and generics), which contains a sulfonamide moiety, states that it is contraindicated for use in patients with an allergy to sulfonamides, while the labels of some other sulfonamide drugs recommend either caution or no precautions at all. The concept of cross-reactivity among sulfonamide drugs, particularly between antibacterial and nonantibacterial sulfonamides, has been controversial for many years.

The FDA has approved Synjardy (Boehringer Ingelheim/Lilly), a fixed-dose combination of the sodium-glucose co-transporter 2 (SGLT2) inhibitor empagliflozin (Jardiance) and metformin (Glucophage, and others), for treatment of patients with type 2 diabetes not adequately controlled on either of these drugs alone or already being treated with both empagliflozin and metformin. It is the third SGLT2 inhibitor/metformin combination to be approved in the US.

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).

Sitagliptin (Januvia) and metformin (Glucophage, and others) are now available in a single tablet (Janumet - Merck) for treatment of type 2 diabetes. The combination is approved by the FDA for use in patients not adequately controlled by sitagliptin or meformin alone or in those already taking both drugs. Metformin is also available in combination with the thiazolidinediones pioglitazone and rosiglitazone and with the sulfonylureas glipizide and glyburide.

The FDA has approved the sodium-glucose co-transporter 2 (SGLT2) inhibitor ertugliflozin (Merck) for treatment of adults with type 2 diabetes, both alone (Steglatro) and in fixed-dose combinations with metformin (Segluromet) and sitagliptin (Steglujan). Ertugliflozin is the fourth SGLT2 inhibitor to be approved in the US. All four are available in combination with metformin and three are available in combination with a dipeptidyl peptidase-4 (DPP-4) inhibitor (see Table 3).