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 More than half the patients in a recent study reported taking
prescription medications, over-the-counter drugs or herbal
supplements along with chemotherapy, and roughly one in six patients
were using products that put them at risk for potentially harmful
drug interactions.
“Patients with cancer frequently use herbal supplements and other
medications,” said lead study author Dr. Allan Ramos-Esquivel of the
University of Costa Rica in San Jose.
“These patients are at high risk of herb-drug interactions and
drug-drug interactions,” he told Reuters Health.
Ramos-Esquivel and colleagues surveyed 149 newly diagnosed cancer
patients about prescription or over-the-counter drugs and herbal
supplements they were taking as they started on new anti-cancer
therapies.
Working with a clinical pharmacist, the researchers identified 36
potential interactions in 26 patients, or 17 percent. The
researchers then notified the oncologist who prescribed the
anti-cancer drugs, and in all cases, oncologists modified the
patients’ therapy.
“The treatment of cancer has shifted in the past decade to the use
of more oral agents,” said John Bossaer of East Tennessee State
University in Johnson City. Bossaer, who wasn’t involved with this
study, has researched drug interactions and anti-cancer drugs.
“Because these newer drugs are taken orally, many patients (and I
fear some clinicians) perceive them as safer,” he told Reuters
Health by email. “While these oral agents do not generally cause the
life-threatening toxicities of IV chemotherapy, they cause many
other side effects, which can be worsened by other medications.”
Herbal-drug interactions, in particular, are concerning because of
unanswered questions and scientific gaps, Bossaer added. Herb-drug
interactions go unnoticed because formal drug interaction studies
don’t typically include them.
“Moreover, many patients do not openly disclose their use of herbal
medications, either because of fear of judgment from their physician
or assuming their use isn’t related to their treatment,” he said.
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In this study, 84 patients, or 56 percent were using herbal
supplements at the time of their first cancer drug prescription.
Using two or more medicinal products in addition to the anti-cancer
therapy was associated with a two times higher risk of a drug
interaction, the authors found.
“It is not as black and white as it may seem,” Bossaer said.
For example, he explained, the prostate cancer drug enzalutamide
decreases the effectiveness of several medications, including
ticagrelor, which is often used after stent placement for heart
disease. A drug interaction may put the patient at greater risk for
a heart attack, which isn’t typically noticed until the heart attack
happens.
“This nuance requires both extensive drug and clinical disease-state
knowledge,” Bossaer said. “This is exactly what clinical pharmacists
are trained to do.”
A limitation of the study is that it relies on the self-reporting
nature of the questionnaire. Future research should better identify
drug and herbal interactions with chemotherapy, the study authors
wrote in the Journal of Oncology Practice.
“Patients or family members of patients should explicitly ask if a
clinical pharmacist has checked their medications for any
significant drug interactions,” Bossaer said. “Some may require a
medication change, and others may require more frequent lab
monitoring.”
SOURCE: http://bit.ly/2tthiMN Journal of Oncology Practice, online
June 19, 2017.
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