Adverse interactions between herbal and dietary substances and prescription medications: a clinical survey.
BACKGROUND
Patients often combine prescription medications with herbal and dietary substances (herein referred to as herbal medicines). A variety of potential adverse herb-drug interactions exist based on the pharmacological properties of herbal and prescription medications.


OBJECTIVE
To determine the incidence of potential and observed adverse herb-drug interactions in patients using herbal medicines with prescription medications.


METHODS
Consecutive patients were questioned about their use of herbal medicines in 6 outpatient clinics. Patients reporting use of these products provided a list of their prescription medications, which were reviewed for any potential adverse herb-drug interactions using a comprehensive natural medicine database. Any potential adverse herb-drug interactions prompted a review of the patient's chart for evidence of an observed adverse herb-drug interaction.


METHODS
The rate of potential and observed adverse herb-drug interactions.


RESULTS
Eight hundred four patients were surveyed, and 122 (15%) used herbal medicines. Eighty-five potential adverse herb-drug interactions were found in 49 patients (40% of herbal medicine users). Twelve possible adverse herb-drug interactions in 8 patients (7% of herbal medicine users) were observed. In all 12 cases, the severity scores were rated as mild, including 8 cases of hypoglycemia in diabetics taking nopal (prickly pear cactus).


CONCLUSIONS
A substantial number of potential adverse herb-drug interactions were detected and a small number of adverse herb-drug interactions observed, particularly in diabetics taking nopal. Screening for herbal medicine usage in 804 patients did not uncover any serious adverse interactions with prescription medications.
Bush
Thomas M
TM
Division of Rheumatology, Santa Clara Valley Medical Center, San Jose, CA, USA.
Rayburn
Keith S
KS
Holloway
Sandra W
SW
Sanchez-Yamamoto
Deanna S
DS
Allen
Blaine L
BL
Lam
Tiffany
T
So
Brian K
BK
Tran
De H
de H
Greyber
Elizabeth R
ER
Kantor
Sophia
S
Roth
Larry W
LW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D041743:Herb-Drug Interactions; D006801:Humans; D008419:Materia Medica / Q000009:adverse effects*; D008875:Middle Aged; D033262:Narration; D004366:Nonprescription Drugs / Q000009:adverse effects*; D008517:Phytotherapy / Q000009:adverse effects*; D010936:Plant Extracts / Q000009:adverse effects; D010946:Plants, Medicinal / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D014481:United States
D008419:Materia Medica; D004366:Nonprescription Drugs; D010936:Plant Extracts