Polypharmacy an 'Escalating Issue' in Older Cancer Patients

Roxanne Nelson

July 14, 2011

July 14, 2011 — The treatment of cancer patients who are older adults is often complicated by the use of multiple medications for comorbid conditions, which increases the risk for adverse drug reactions and drug interactions. New strategies are needed to overcome this escalating issue of polypharmacy in elderly cancer patients, according to a review published online July 7 in the Lancet Oncology.

Polypharmacy presents a number of challenges for physicians who treat older patients with cancer, and greater recognition of the problem is needed, say the authors, Judith Lees, BPharm, senior pharmacist at the Royal Adelaide Hospital Cancer Centre, in Australia, and Alexandre Chan, PharmD, from the National University of Singapore and the National Cancer Centre Singapore.

In their review, they propose some practical solutions to guard against the negative outcomes of polypharmacy, which include discontinuing potentially inappropriate medications and increasing awareness by health professionals of clinically meaningful drug interactions.

"In the setting of an older cancer patient, if the cancer diagnosis now reduces their life expectancy, it makes sense that medications for long-term benefit might no longer be useful and a consolidation process is the next valid step, in consultation with all treating teams and the patient," Ms. Lees said in an interview.

In the next 20 years, about 70% of all cancers diagnosed in the United States will be in older adults. "This issue is not going away, so we need to be aware and work on management strategies," she said.

"Our review found that rational polypharmacy is increasing in older patients as more therapeutic options become available for disease treatment and/or prevention," Ms. Lees told Medscape Medical News. "This does not necessarily mean that medications were overprescribed; however, some studies we reviewed did indeed find that drug problems existed as a result of multiple medications before the patient started cancer treatment."

Cancer therapy itself often requires multiagent regimens that include both antineoplastic agents and supportive therapies. But cancer treatment regimens are often further complicated with over-the-counter (OTC) medications and, increasingly, complementary and alternative medicines (CAM). The authors also point out that the individuals at the highest risk for polypharmacy are those who see multiple physicians, have prescriptions dispensed at several pharmacies, have concurrent comorbidities, and who are elderly.

Better Assessment Needed

William Douglas Figg Sr., PharmD, MBA, who was approached by Medscape Medical News for independent comment, agreed that multiple prescribers and multiple pharmacies are a large part of the problem. Another issue is that oncologists are often hesitant to alter medications prescribed by other specialists.

"There is also clearly a medication history problem, one that could be cleaned up with electronic medical records," said Dr. Figg, who is senior scientist and head of the clinical pharmacology program and molecular pharmacology section at the Center for Cancer Research, National Cancer Institute, in Bethesda, Maryland. "OTC is often forgotten, but more importantly, the underreporting of herbal and CAMs is a real issue."

Drug–CAM interactions are a real concern, he emphasized. "We know that some of those agents can either increase metabolism or decrease metabolism," he said. "Some can alter absorption. These might alter the anticancer agents we are giving."

"I think the bottom-line message is that we need to do a better job of making sure we know all the medications elderly patients are taking," said Dr. Figg. "Ensure there is no drug–drug interaction or drug–CAM interaction, and try to streamline their medications. Also make sure they are using 1 pharmacy to get all of their medications."

Polypharmacy Common

Previous research suggests that polypharmacy is common in elderly cancer patients, note the authors. A Canadian study reported that 92% of patients 65 years or older were taking a median of 5 prescribed medications before the start of any cancer treatment (Drugs Aging. 2009;26:519-536). That study might have underestimated total medication use because CAMs were not recorded.

Another study conducted at a university hospital in the United States found that 96% of patients 44 to 85 years of age were taking a mean of 5.5 prescription drugs in the 3 days before their next cycle of chemotherapy (J Oncol Pharm Pract. 2008;14:123-130). In addition to the prescribed medications, 71% of patients reported using a mean of 2.2 OTC drugs, and 69% were taking vitamins, herbs, or other supplements.

The authors note that patients might not volunteer information or discuss their use of CAMs with their physician, but that it is essential for all members of the medical team to be aware of any such medicines that their patient is taking to prevent possible adverse outcomes.

"Healthcare professionals need to ask and patients need to know the importance of telling us everything they are taking so that we can ensure no adverse drug outcomes," said Ms. Lees.

Managing Polypharmacy

After patient medications have been established, either all patients or those at high risk for drug interactions need to be screened, Ms. Lees and her coauthor write. Another important issue is the ability to recognize the clinical significance of many reported drug interactions and to assess whether a drug interaction is responsible for an adverse event or whether the malignancy might be contributing to it.

Thus, improved recognition of clinically meaningful drug interactions is imperative. "A technique for investigation of drug reactions specifically in patients receiving chemotherapy might prove a practical solution, especially in elderly patients on more than 1 medication," they write.

Other recommendations for managing polypharmacy in this population include the rational discontinuation of drugs that are potentially inappropriate, that can potentially be discontinued in collaboration with a patient's primary care doctor, and that might include agents such as tricyclic antidepressants and sedating antihistamines.

Another recommendation, they write, is to consider changing drugs that are commonly used by cancer patients and are associated with a high frequency of adverse drug events, such as anticoagulants (specifically warfarin).

They also recommend assessing drugs used for primary or secondary prevention for their appropriateness, in terms of long-term benefit, in patients with metastatic disease.

The authors have disclosed no relevant financial relationships.

Lancet Oncol. Published online July 7, 2011. Abstract