The United States wasted $418 billion last year on unneeded medications, with the poorest states bearing the brunt.

Mississippi, with the lowest median household income in the country, wasted the most money on prescription medications lacking clinical value, overspending by 1,622.76 per resident. The next seven most wasteful states were either in the South or pretty close: Arkansas, Alabama, Kentucky, Tennessee, South Carolina, New Mexico, and Oklahoma.

The U.S. in 2008 spent 15.2 percent of its GDP on health care, far more than any other country in the world, with 10 percent of that money going to prescription drugs — by far, America's third most profitable industry.

Dr. Steve Miller presented the data Tuesday in Orlando at a meeting held by Express Scripts, one of the country's largest pharmacy benefits management company. Miller said the U.S. wastes money where people can least afford it, as the health care system hemorrhages money in spending on expensive prescription drugs and pharmacies when alternatives exist. Waste also happens when patients fail to adhere to their medication therapies, he said.

In the breakdown:

"$55.8 billion was spent unnecessarily on higher-priced medications when more affordable, clinically equivalent alternatives were available.

$93.1 billion could have been saved if patients would have used the most cost-effective and clinically appropriate pharmacies, including home delivery and specialty. This savings includes $33.5 billion in lower drug costs, as well as $59.6 billion in avoided medical costs attributed to the higher adherence rates associated with home delivery and specialty pharmacies.

An additional $269.4 billion was spent on avoidable medical and pharmacy expenses as a result of patients not remaining adherent to their medication treatments. This total does not include the $59.6 billion in adherence savings directly associated with better pharmacy choices."

Millers said Southern states, those with the poorest incomes and highest rates of chronic disease, wasted the most, compared to the least wasteful states in the Northeast and Midwest. Vermont wasted the least amount of money but still squandered just over $1,000 per resident, for a total of approximately $626 million.