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Kanker patiënten lopen groot risico met verschillende medicijnen.*

Uit een Canadese studie blijkt dat er nogal wat fout kan lopen met de verschillende medicijnen die gebruikt worden door kankerpatiënten. Kankerpatiënten krijgen vaak verschillende medicijnen waaronder medicijnen ter bestrijding van de kanker en wellicht andere aandoeningen en medicijnen om allerlei bijwerkingen te bestrijden. Daardoor kunnen er verschillende wisselwerkingen komen met nare gevolgen. De onderzoekers vonden 276 medicijncombinaties die potentieel gevaar kunnen opleveren. 9% van die combinaties zijn zeer ernstig en 77% is gematigd ernstig. Bij onderzoek onder 405 kankerpatiënten bleek een derde van hen tenminste 1 potentieel gevaarlijke combinatie te nemen. 8% van de patiënten bleken ook nog eens hetzelfde medicijn meerdere malen voorgeschreven te krijgen.

Cancer Patients Are At High Risk For Potential Drug Interactions

Potential drug interactions from prescribed medications are common among cancer patients and may cause unnecessary harm, according to a study in the Journal of the National Cancer Institute.
Cancer patients often take several medications at the same time, not only for treating their cancer but also for side effects and other secondary illnesses. Because of this, they can be at high risk for adverse drug interactions and duplicate medications. Consequences of these interactions can range from inactivation of cancer-fighting medications to severely injuring or killing the patient.
Rachel Riechelmann, M.D., of the Princess Margaret Hospital in Toronto, and colleagues gave 405 cancer patients a questionnaire about the medications they had taken in the last four weeks. Their responses were analyzed using a drug interaction software program that could identify potential interactions and rank them by severity.
Nearly a third of patients were exposed to at least one potential drug interaction. The researchers identified 276 drug combinations with the potential to interact. About nine percent of the interactions considered of major severity - risk of death - and 77 percent of moderate severity - risk of serious health problems. About eight percent of the patients received duplicate medications.
The researchers found that some of the drugs interacted with anticancer medications. The most common were warfarin (a drug to prevent blood clots), antihypertension drugs, aspirin and anticonvulsants. Warfarin stood out because it can cause hemorrhages when used with certain chemotherapy medications, and the interaction can interfere with its metabolism. Additionally, patients with brain tumors were at particularly high risk since they are often prescribed anticonvulsants.
"We suggest that patients at high risk… be routinely screened for potential drug interactions. The development of medication databases and computerized physician medication order entry linked to screening electronic programs could help health professionals to identify dangerous drug combinations and monitor prescriptions of agents with high risks of interactions," the authors write.
In an accompanying editorial, Peter Norton, M.D., of the University of Calgary, and G. Ross Baker, Ph.D., of the University of Toronto, agree that a better system for tracking patients' medications is needed. "We believe that such coordination and communication have the potential to substantially reduce the incidence of and mitigate possible harm from the potential drug interactions that have been discovered by Riechelmann [and colleagues]. In other high-risk industries, such as aviation and the offshore oil industry, many errors result from poor coordination and communication, and in these areas, strategies to improve team coordination and communication have led to reductions in incidents," the authors write.
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Article: Riechelmann RP, Tannock IF, Wang L, Saad ED, Taback NA, Krzyzanowska MK. Potential Drug Interactions and Duplicate Prescriptions among Cancer Patients. J Natl Cancer Inst 2007; 99: 592-600 Editorial: Norton PG, Baker GR. Patient Safety in Cancer Care: A Time for Action. J Natl Cancer Inst 2007; 99: 579-580

Department of Medical Oncology and Hematology, Princess Margaret Hospital, 610 University Ave, Toronto, ON, M5G 2M9, Canada.

BACKGROUND: Cancer patients receive numerous medications, including antineoplastic agents, drugs for supportive care, and medications for comorbid illnesses. Therefore, they are at risk for drug interactions and duplicate prescribing. METHODS: A questionnaire eliciting information on demographics and medications taken in the previous 4 weeks was given to adult outpatients receiving systemic anticancer therapy for solid tumors. The Drug Interaction Facts software, version 4.0, was used to identify potential drug interactions and to classify them by level of severity (major, moderate, or minor) and the strength of scientific evidence for them (using categories [1-5] of decreasing certainty). Summary statistics and logistic regression were used to analyze the data. All statistical tests were two-sided. RESULTS: The survey was completed by 405 patients. We observed 276 potential drug interactions, and at least one potential interaction was identified in 109 patients (27%; 95% confidence interval [CI] = 23% to 31%). Of the potential interactions, 25 (9%) were classified as major and 211 (77%) as moderate. Nearly half (49%) of potential interactions were supported by level 1 or 2 scientific evidence. Most potential drug interactions (87%) involved non-anticancer agents such as warfarin, antihypertensive drugs, corticosteroids, and anticonvulsants, but some (n = 36, 13%) involved antineoplastic agents. In multivariable analysis, increased risk of receiving drug combinations in which there were potential drug interactions was associated with receipt of increasing numbers of drugs (odds ratio [OR] = 1.4 per additional drug, 95% CI = 1.26 to 1.58, P<.001 from the Wald chi-square test), type of medication (drugs to treat comorbid conditions versus supportive care medications only; OR = 8.6, 95% CI = 2.9 to 25, P<.001), and the presence of brain tumors. Thirty-two (8%) patients were exposed to duplicate medications, most often corticosteroids, proton pump inhibitors, or benzodiazepines. CONCLUSION: Potential drug interactions were common among cancer patients and most often involved medications to treat comorbid conditions. Duplicate medications were infrequent.  (Mei 2007)  

 

 

 

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