Spending on prescription drugs continues to rise but not at the white-hot pace of a few years ago.

Does your wallet beg to differ? The company reporting this trend considered drug utilization as well as drug costs. Most of last year's drug spending increase was due to a 5.4 percent jump in utilization, while unit costs rose 3.1 percent, says the report.

In other words, more people are using certain types of prescription drugs — and some of them might surprise you.

Slower Growth

In 2004, the cost of prescription drugs increased 8.5 percent, says the 2005 Drug Trend Report from Medco Health Solutions. The New Jersey-based company manages prescription drug programs and operates the largest mail-order and Internet pharmacies.

Prescription drug spending has been dropping for the past five years from a high of 16.4 percent in 1999, says Medco. In 2003, the spending growth figure was 10.2 percent.

Numbers are based on Medco's clients. The report mainly focuses on drug classes, not specific brand names.

Top 10 Trend Drivers

Judging by the report, our hearts, bones, aches and pains, mental health, and diabetes are driving many prescription drug purchases.

Lipid-lowering drugs had a 16.5 percent increase in use and remain the "largest contributor to plan spending and the largest single driver of drug trend," says Medco.

Drugs used to treat arthritis had "exceptionally high" spending growth of 49.5 percent, according to the report. While many of these drugs are used to treat arthritis, they have several other indications for treatment of conditions, such as psoriasis.

Eight other drug classes were also named top trend drivers: high blood pressure medications, respiratory drugs, anticoagulant/antiplatelet drugs, diabetes drugs, seizure medications, osteoporosis drugs, narcotic pain relievers, and drugs for cancer and transplants.

Surge in Drugs for ADHD, Sleep Problems

Spending on ADHD drugs grew 30 percent in 2004 — and not just among kids.

Use of ADHD drugs grew 23 percent among young adults (aged 20-34), who spent 40 percent more on those prescriptions than before. More baby boomers and seniors also used ADHD drugs in 2004. Use was up 33 percent in adults aged 39-49 and 36 percent in adults aged 50-64.

More Americans were also apparently tossing and turning at night, then calling their doctors about it in the morning.

Spending on drugs for sleep woes, including insomnia, rose 19 percent, says Medco. Cost hikes and increased use each accounted for about 9 percent of that growth, says the report, noting that generic versions of a leading drug in that class are expected in 2006.

Antibiotics, Non-Narcotic Pain Relievers Down

Spending declines were reported in antibiotics, estrogen/progestin therapy, antianxiety drugs, and cough and cold remedies.

Other drug classes cooled off a bit. Non-narcotic pain relievers, antidepressants, and ulcer and heartburn drugs showed slow rates of spending growth, says Medco.

Some of those shifts may stem from recent headlines.

Medco's report notes concerns about possible health risks of Cox-2 inhibitor pain relievers, controversy about use of antidepressants among children and adolescents, findings about women's hormone replacement therapy, and "growing clinical interest in prudent prescribing of antibiotics" among children.

Antibiotic use was down 7.2 percent overall, and it dropped 12.8 percent among children, says Medco.

Use by Children, Teens, Young Adults

The report offers a snapshot of the most commonly used drug classes by each age group:

"Children primarily take medications for respiratory conditions (including asthma and allergies), behavioral disorders, and infections," says the report.

For young adults (aged 20-34), oral contraceptives, antidepressants, antibiotics, and allergy drugs were commonly used drug classes. Spending on antidepressants, oral contraceptives, and antibiotics slowed or declined in that age group.

Though young adults are often considered to be in the prime of life, they showed high growth for heart-related drugs (30 percent growth for anticoagulant/antiplatelet drugs and 11 percent for lipid-lowering drugs). "This signals the emergence of cardiovascular conditions as an important driver of medication use in this age group," says the report.

Use by Baby Boomers, Seniors

"For members aged 35 to 49, central nervous system drugs (neurology, mental health, and pain) account for the largest share of drug spending," says Medco. Rheumatological and lipid-lowering drugs were the strongest trend drivers in that age group.

For adults aged 50-64, lipid-lowering drugs and drugs for high blood pressure, depression, and diabetes were commonly used drug classes.

As for seniors (aged 65 and older), "the most commonly used medications are for cardiovascular conditions, including high cholesterol, high blood pressure, and heart failure," says the report.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Medco Health Solutions: "2005 Drug Trend Report." News release, Medco Health Solutions.