Use of prescription and nonprescription medications and supplements by cancer patients during chemotherapy: questionnaire validation.
BACKGROUND
Cancer patients take medications for coexisting disease and self-medicate with over-the-counter drugs (OTCs). A complete analysis of the use of prescription drugs, OTCs, and supplements during cancer treatment has never been done.


METHODS
The study developed and validated a self-administered questionnaire on the use of concomitant medications by patients undergoing treatment with chemotherapy. The questionnaire listed 510 prescription medications, OTCs, and supplements (including vitamins, minerals, and herbs). Fifty-two subjects completed the questionnaire while visiting the infusion clinic to receive chemotherapy. On a subsequent visit the subjects brought their medications to the clinic and a pharmacist reviewed their completed questionnaire.


RESULTS
Ninety-six percent of the subjects reported taking prescription medications within 3 days prior to chemotherapy, 71% reported taking OTCs and 69% reported use of supplements. The subjects took an average of 5.5 (range 0-13) prescription drugs, 2.2 (0-20) OTCs, and 1.9 (0-11) supplements. Twenty-one drugs were each taken by at least 10% of the subjects. Acetaminophen was taken by 59.6% of the subjects. One subject reported taking five acetaminophen-containing drugs. The questionnaire's sensitivity was 92.0%, specificity 99.9%.


CONCLUSIONS
Within 3 days prior to chemotherapy, subjects took an average of 9.6 concomitant medications, many of which alter drug metabolism and or disposition. In clinical trials, multivariate analysis of all concomitant medications could add to clinically relevant data to identify drug interactions that negate or potentiate the efficacy of cancer treatment regimens. In some instances, apparent resistance of tumors to chemotherapy may be the result of drug interactions.
Hanigan
Marie H
MH
Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. marie-hanigan@ouhsc.edu
Dela Cruz
Brian L
BL
Thompson
David M
DM
Farmer
Kevin C
KC
Medina
Patrick J
PJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D003627:Data Interpretation, Statistical; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D004363:Drug Utilization; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy*; D004366:Nonprescription Drugs; D028321:Plant Preparations; D055553:Prescription Drugs; D015203:Reproducibility of Results; D012651:Self Medication; D011795:Surveys and Questionnaires; D014815:Vitamins
D000970:Antineoplastic Agents; D004366:Nonprescription Drugs; D028321:Plant Preparations; D055553:Prescription Drugs; D014815:Vitamins