Americans spent more money on insulin glargine in 2015 than any other drug, and more than half of the 20 biggest-selling drugs for the year are regularly prescribed to patients with diabetes, according to the Agency for Healthcare Research and Quality.

The estimated total expenditure for insulin glargine was $11.1 billion in 2015 – an increase of 81% in just 2 years, data from the Medical Expenditure Panel Survey (MEPS) show. The cholesterol-lowering drug rosuvastatin was the second highest–selling drug in 2015 with total spending of $6.8 billion. Other drugs among the year’s 10 best sellers that are used regularly by patients with diabetes were atorvastatin (fourth overall at $6.3 billion), insulin aspart (seventh at $4.8 billion), sitagliptin (eighth at $4.6 billion), insulin isophane (ninth at $4.4 billion), and pregabalin (tenth at $4.2 billion).

Drugs used by patients with diabetes also took up half of the next 10 spots in the list: gabapentin was 11th, insulin detemir was 12th, metformin was 14th, insulin lispro was 16th, and metformin-sitagliptin was 20th, according to the MEPS data.

The drugs in the MEPS top 10 for 2015 – the most recent year for which data are available – that are not commonly prescribed for diabetes were the asthma/chronic obstructive pulmonary drug fluticasone-salmeterol (third at $6.7 billion), the gastroesophageal reflux disease drug esomeprazole (fifth at $5.3 billion), and aripiprazole (sixth at $5.2 billion), which is used to treat schizophrenia and bipolar disorder.