The Philadelphia Inquirer

PHILADELPHIA – Dr. James Kmetzo knows that Diltiazem is usually the drug of choice for high blood pressure.

But then his choices explode. Cardizem, Dilacor and Tiazac are all brand names for Diltiazem. But should he prescribe Cardizem CD, Cardizem SR, Cardizem LA, Dilacor XR or Tiazac? All four come in varying doses, some taken once a day, some twice, some crushable, others not.

Most of the time, it’s the insurance coverage and pharmacist that decide. “I know that it’s Diltiazem and I can write any two letters after it and it gets filled correctly,” said Kmetzo, a cardiologist.

Not always. Last month, the Food and Drug Administration called a closed-door meeting with pharmaceutical companies and watchdog groups to address the issue. They agreed to study the problem, but the solution remains elusive.

Many of the CD, XL and SR medications are designed to treat heart disease or mental illness, such as depression or anxiety. Most are higher-dose forms meant to be released slowly. Doctors say taking a more potent form incorrectly can result in seizures or a sudden drop in blood pressure, leading to fainting, falls and even death.

In 1996, an 83-year-old woman died after mistakenly being switched from immediate-release medication for her high-blood pressure to a time-release formula. By chewing the Cardizem CD tablets instead of swallowing them, she released the drug more quickly into her bloodstream, according to the Institute for Safe Medication Practices, an industry watchdog group.

Experts say the problem worsened as more drugs in multiple forms came on the market. Several pharmacists said they typically saw incorrect prescriptions two or three times a shift.

In an ongoing study at the Albany Medical Center, the director of pharmacy found that more than 600 errors annually were the result of those two letters at the end of a drug’s name.

Patients often aren’t paying attention. Consumers read their medication labels less than half the time, according to a 2005 study by the American Pharmacists Association.

“There are a lot of errors, and some have had a significant impact on patients, causing permanent impairment and death,” said Linda Hanold, chair of the National Coordinating Council for Medication Error Reporting and Prevention, which coordinated the conference.

“It’s not an epidemic, but as more and more drugs enter the market, there’s more confusion, and we need to address the issue now when it’s still early.”

The suffix issue started about 20 years ago when drug companies began developing new versions of medication. The original goal had good intentions – to develop slower-releasing pills to be taken once or twice a day instead of multiple times.

Because it was the same medication, the drug companies had to find a way to distinguish the new time-release forms from the earlier pills. They started adding two letters at the end of the name: XL, CD, SR and LA.

The letters have no standard meaning. The letters “SR” on one drug, such as the blood pressure medicine Verapamil SR, means it is given once a day. On another drug, Wellbutrin SR, it’s twice a day. Sometimes generic version letters do not match the brand name.

There are no FDA regulations on suffixes, said Michael Cohen, president of the Institute for Safe Medication Practices, which wants the names to be standardized. When the letters started appearing, he said, mistakes started happening almost immediately. In the last decade, his group received hundreds of medication mix-up reports due to suffix mistakes.

“Walk into any pharmacy and ask about this problem – everyone is talking about it,” said Cohen, a pharmacist himself. “There’s no directory of these suffixes, and we don’t know what they mean; the letters are just meaningless.”

Richard Centafont, director of pharmacy for Philadelphia’s Main Line Health, said it’s a matter of vigilance on the part of the doctor, the pharmacist and the patient. “We see some doctors forgetting to write them down, and the suffixes themselves are so confusing that they can be construed for Roman numerals,” Centafont said. “It can be very dangerous.”

The pharmaceutical industry acknowledges the problem but does not know how to fix it. The FDA and other agencies do not specifically look at mistakes due to suffix errors.

“We don’t know how the mistakes are occurring and how large the problem is,” said Rosemary Cook, an assistant vice president for the Pharmaceutical Research and Manufacturers Association in Washington, the industry’s main lobbying group.

FDA officials say they take suffixes into consideration when approving a drug name and have changed some names. One problem with regulating names is how to address those already on the market.

“That’s our dilemma, because the last thing we want to do is cause more confusion,” said Carol Holquist, director for the division of medication errors in the FDA’s office of drug safety. “What was promising about the meeting was that everyone recognized it was a problem.

For Kmetzo, the best solution is to streamline drug production.

“We don’t need that many different Cardizem drugs, so the industry is bringing it on themselves,” Kmetzo said. “Go work on other drugs instead that we can use.”