The rising rates of diabetes mean the condition now accounts for nearly a 10th of the annual NHS drugs bill in England, official figures show.
Some £725m was spent on diabetes drug in 2010-11 - 8.4% of the total bill.
The figure was 41% more than the £513m spent five years ago when diabetes accounted for 6.6% of the budget, the NHS Information Centre data showed.
This compares to an 11% rise in the overall cost of the drugs bill between the two periods.
One in every 25 prescription items now dispensed is for diabetes, the data showed.
Most of the rise is down to the treatment of type 2 diabetes, which is linked to obesity and unhealthy lifestyles.
Many people are on a combination of drugs to try to keep their blood sugar levels under control, and two out of three items now dispensed manage the body's own production of insulin.
The next most commonly issued drugs are injectable insulins, which are vital when the pancreas cannot produce enough of the hormone itself.
Insulin works by keeping the level of sugar in the bloodstream within a normal range.
Bridget Turner, from Diabetes UK, said while the figures seemed high, the use of such drugs helped to prevent even more serious problems developing.
"This report reinforces that diabetes is one of the biggest health challenges this country faces.
"The long-term costs of poor diabetes management, such as caring for someone who's had a heart attack or stroke, lost their sight or lower limb, far outweigh those of the drugs that help prevent such complications."
The rise in spending on diabetes drugs comes after the number of people with the condition has jumped by nearly a fifth in the past five years to over 2.3m.
But the Department of Health said the rise in spending was not solely linked to the trend in cases.
A spokeswoman added: "The continued upward trend is not down to rising cases alone and a number of factors need to be considered such as increased access to new and more effective medicines and the move towards prescribing medicines preventatively."
