Although there aren't any perfect solutions to creating a formulary free of drug-drug interactions, there are things you can do to limit problems.
Sometimes even the best-laid treatment plans can crash upon a pharmacy counter, where dangerous — even deadly — combinations of prescription drugs are too often dispensed.
Pharmacists don't want to make errors, Michael Cohen, president of the Institute for Safe Medication Practices, an advocacy group in Warminster, Pa., concedes. "But," he asks, "when the system puts them in a position of having to fill over two hundred prescriptions in an eight-hour shift, with numerous telephone interruptions and no chance to go to the bathroom, do you really believe that they're not going to make an error at some point?"
This is not to imply that pharmacists' errors are the only cause of deadly drug interactions. In such a quickly changing field, many variables come into play.
In the past 18 months, for instance, the Food and Drug Administration has removed several drugs from the market because they were dangerous; the FDA has issued warnings about others. Diet drugs, antihypertensive medications and pain killers have been taken off shelves because they interacted negatively with other drugs, making some people sick and killing others. An FDA warning has even been issued about an antacid.
Most health care professionals agree that it's nearly impossible to create a formulary in a hospital or pharmacy chain that's completely free of any danger of unsafe drug interactions. However, some ways HMOs can greatly minimize the risks are by:
Encouraging patients to tell each doctor and/or pharmacist they visit about all current over-the-counter or prescription medications they're taking as well as important clinical conditions that may contraindicate specific drugs.
Telling physicians to ask patients about current medications when taking histories. (Having the patient fill in a form is not enough.)
Prodding pharmacists to make full use of current computer systems instead of ignoring the built-in software warnings that are designed to flag drug problems.
Asking pharmaceutical companies to be more aware of the fact that the names they're giving products, as well as the packaging, could confuse busy physicians and pharmacists.
Tim Birner, director of pharmacy for Harvard Pilgrim Health Care in Boston, points out that formularies should serve as a guide "for physicians to implement the best therapeutic regimen for each patient." This, along with the pharmacy and therapeutics committee's decisions about a drug's efficacy, safety and cost, are the criteria Harvard Pilgrim uses to decide what to add to its formulary. Birner says, "We ask, 'Why aren't people compliant with this medicine? Does it make them drowsy or bother their stomachs?'"
And formulary managers, reiterates Cohen, should be aware of working conditions. Sometimes a desire to cut costs may be a temptation to break tablets in halves or quarters. For instance, a physician may prescribe 36 milligrams of a medication to be taken in four doses a day. (Nine milligrams per pill.) The pharmacist may only have pills containing 18 milligrams of the medication. Cutting the 18-milligram pills in half solves the problem, right? Maybe. "It's the same dose, but the patient gets confused and sometimes winds up taking more or less than he should," says Cohen.
He suggests that hospital and HMO formulary managers have "continuous quality improvement" programs at their pharmacies. This, he added, could involve counseling patients, separating medications that have similar names and/or packaging, and reporting on errors at other pharmacies.
Cohen also proposes that pharmaceutical manufacturers and pharmacists assist the FDA in deciding whether the name or packaging of a proposed medication may cause physicians or pharmacists to confuse it with other products already on the market.
But don't hold your breath for brand name reviews, warns Richard Waltermire, senior vice president of Pharmacy Gold, the large pharmacy benefit manager.
"Pharmaceutical companies do have advisory committees that will ask pharmacists from different disciplines to review a product," says Waltermire, "but manufacturers spend a lot of money on developing the name and so, unless there are some real safety and danger issues out there, the manufacturers are not going to change a name just on a recommendation."
Waltermire, like Harvard Pilgrim's Birner, thinks that preventing adverse drug-drug interactions begins with the pharmacy and therapeutics committee, which should carefully outline the criteria a patient must meet in order to be eligible for a drug that is coming onto the formulary.
"Who are the perfect candidates?" asks Birner. "How many do you cover? We don't want to try to sell this drug to everybody who can pay for it."
Pharmacy guidelines were created to prevent serious and avoidable toxicity in patients receiving multiple medications, points out Robert Fontana, M.D., gastroenterologist and assistant professor of internal medicine at the University of Michigan in Ann Arbor. "However, in certain instances, the prescribing physician may be aware of the increased risk and choose to treat the patient as requested and override the precautionary warning," he says. "I am concerned that formulary managers may create too many detailed rules and guidelines that can impair the delivery of quality care. From my own experience, pharmacy and formulary committees can at times excessively restrict the availability of effective medications due to safety concerns that may actually result in poorer quality of care, delay in treatment and prolonged hospitalization. These issues are particularly problematic for patients who are seriously ill or have refractory systems from a clinician's perspective."
Like much else in this fast-paced world, information plays a crucial role. Putting that information into computers derails many potential problems. Pharmacy benefits managers as well as pharmacists use hardware and software that are often sold as a unit by vendors. This equipment provides up-to-date data on negative drug interactions, recent drug trials and pricing information. Sounds good, right? But just because most pharmacists have computers, doesn't mean they have the same software. And if they do, it doesn't mean that they know how to use it properly.
"Pharmacists have the option to turn off drug-disease checking and drug-contraindication checking if they choose to," says John Frady, a research manager for QS1 of Spartanburg, S.C., a software vendor. "When we send the system, it's turned on for all the edits."
QS1 takes drug information compiled by companies like First Data Bank, a supplier of drug pricing and interaction information based in San Bruno, Calif., and puts it into software that is sold to independent pharmacies all over the country. The information includes names of prescription drugs; data on contraindications, duplicate therapies and drug monographs; and lists of prices. The software, Frady adds, can show that a particular drug is contraindicated for any disease the patient may have, as well as other medications the patient may be taking.
One thing the software can't do, however, is keep the drug interaction feature on if the pharmacist elects to turn it off. "It's not what should be, but in reality this is what's occurring," says Jack M. Rosenberg, Pharm.D., Ph.D., professor of pharmacology and pharmacy at Long Island University and director of the International Drug Information Center. "Everything should be done to prevent this." But, in fact, little can be done because, when you come right down to it, HMOs cannot force pharmacists to keep the drug-drug interaction warning light on. From such stubbornness mistakes are born.
"You can have a physician prescribe a combination that's contraindicated," says Rosenberg. "The pharmacy goes ahead and fills it. God knows why. The nurse administers it. And most of the time nothing happens. Pharmacists not catching combinations that are known to be contraindicated happens all the time."
But pharmacists aren't the only ones who need to be on their toes.
"If you're a health professional, there's no excuse to not keep up to date with what's happening with all the drugs," says Rosenberg. "Whether you're a physician, nurse, pharmacist, whatever: Have an awareness! And don't override software programs that are in place to protect you. Most of the good pharmacy systems have provisions to avoid these drug interactions."
And although responsibility often rests with pharmacists and physicians for harmful drug-drug interactions, it may someday shift to the managed care company, warns Alan Lyles, Ph.D., assistant professor of health policy and management at Johns Hopkins University.
"If a managed care plan takes an insurance premium to provide comprehensive services for people enrolled, there is an expectation of performance of duty that will probably grow to include that," he says.
Martin Kohl , a free lance, has written about law and medicine for 30 years.