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Cited by 115Complementary and Alternative Medicine StudiesPharmaceutical Practices and Patient OutcomesNutrition and Health Studies

Prevalence of drug-herb and drug-supplement interactions in older adults: A cross-sectional survey

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Agbabiaka, Taofikat B, Spencer, Neil H, Khanom, Sabina, Goodman, Claire·2018·British Journal of General Practice
DOI 10.3399/bjgp18x699101PMC PMC6145997
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Abstract

Background Polypharmacy is common among older adults, with increasing numbers also using prescription drugs with herbal medicinal products (HMPs) and dietary supplements. There is no reliable evidence from the UK on concurrent use of HMPs and dietary supplements with prescription drugs in older adults. Aim To establish prevalence of concurrent prescription drugs, HMPs, and dietary supplements among UK community-dwelling older adults and identify potential interactions. Design and setting Cross-sectional survey of older adults registered at two general practices in South East England. Method A questionnaire asking about prescription medications, HMPs, and sociodemographic information was posted to 400 older adults aged ≥65 years, identified as taking ≥1 prescription drug. Results In total 155 questionnaires were returned (response rate = 38.8%) and the prevalence of concurrent HMPs and dietary supplements with prescriptions was 33.6%. Females were more likely than males to be concurrent users (43.4% versus 22.5%; P = 0.009). The number of HMPs and dietary supplements ranged from 1 to 8, (mean = 3, median = 1; standard deviation = 1.65). The majority of concurrent users (78.0%) used dietary supplements with prescription drugs. The most commonly used dietary supplements were cod liver oil, glucosamine, multivitamins, and vitamin D. Others (20.0%) used only HMPs with prescription drugs. Common HMPs were evening primrose oil, valerian, and Nytol Herbal ® (a combination of hops, gentian, and passion flower). Sixteen participants (32.6%) were at risk of potential adverse drug interactions. Conclusion GPs should routinely ask questions regarding herbal and supplement use, to identify and manage older adults at potential risk of adverse drug interactions.

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Crossref · 10.3399/bjgp18x699101

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  • Supplement-drug interactions are frequently omitted at history taking because of the perception that what is natural is harmless.

    “Unlike drug–drug interactions, those involving “natural” products are frequently omitted at history taking, because of the perception that what is natural is harmless [1,3].”

    From Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review (2026) · cites this paper as [3]

    The Discussion (Comparison with existing literature; page unavailable) says some patients do not consider herbal products and supplements to be medicines and may not disclose them even when questioned. It does not say omissions are frequent relative to drug–drug interactions or attribute them to a belief that natural products are harmless. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Between 5% and over 80% of older adults combine supplements with prescription drugs, and a substantial proportion carry at least one potential interaction.

    “Population studies report that between 5% and over 80% of older adults combine supplements with prescription drugs, and a substantial proportion carry at least one potential interaction [3,4,5,6,7].”

    From Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review (2026) · cites this paper as [3]

    The Discussion’s comparison with existing literature reports concurrent use ranging from 9% to 88.3%, supporting the upper end but not the claimed 5% lower end. The Discussion summary reports that about one in three concurrent users was at risk of a potential interaction. (LLM, conf=0.86)

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  • Physicians rarely initiate discussion about supplement use, amplifying risk.

    “The failure of patient–clinician communication about supplement use amplifies this risk, as physicians rarely initiate the discussion [1,3].”

    From Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review (2026) · cites this paper as [3]

    The Discussion (Comparison with existing literature; Implications for practice, page unavailable) says patients may not disclose supplements even when questioned and recommends direct questioning to identify potential interactions. It does not establish that physicians rarely initiate these discussions or measure how often they do so. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • Concurrent, often undisclosed use of berberine with prescription drugs is common in older adults.

    “Concurrent, often undisclosed use with prescription drugs is common in older adults, yet berberine is far from inert.”

    From Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review (2026) · cites this paper as [3]

    The Results (‘Prevalence and pattern of concurrent use’) report that 33.6% of surveyed older adults used herbal products or supplements with prescription drugs. The Discussion (‘Comparison with existing literature’) says some patients may not disclose such use, even when questioned. Neither passage establishes that berberine use specifically is common or often undisclosed. (LLM, conf=0.87)

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Research works printed but not linked: 1

  1. [26]Dergal JM Gold JL Laxer DA Potential interactions between herbal medicines and conventional drug therapies used by older adults attending a memory clinic Drugs Aging 2002 19 11 879 886 12428996

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Authors
Agbabiaka, T. B., Spencer, N. H., Khanom, S., & Goodman, C.
Affiliations
University of Hertfordshire (GB)
ORCID
Venue
British Journal of General Practice
Publisher
Royal College of General Practitioners
Published
2018-09-24
Volume
68
Issue
675
Pages
e711-e717
ISSN
  • 0960-1643 (ISSN-L)
  • 1478-5242
DOI
10.3399/bjgp18x699101
PMC
PMC6145997
OpenAlex
W2894171928
Cited by
115
References
42
Citations by year
2026: 15 · 2025: 10 · 2024: 14 · 2023: 18 · 2022: 21 · 2021: 19 · 2020: 11 · 2019: 6 · 2018: 1
FWCI
12.70
Type
journal article
Language
en
Open access
Licence
cc-by-nc
Locations
  • British Journal of General Practice (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • University of Hertfordshire Research Archive (University of Hertfordshire) (submittedVersion, cc-by-nc)
  • University of Hertfordshire Research Archive (University of Hertfordshire) (submittedVersion)
Funders
National Institute for Health and Care Research (HTA/13/75/01, 12/192/10, HTA/12/192/10, 13/75/01, NF-SI-0515-10103)
Topics
  • Health Sciences › Medicine › Complementary and alternative medicine › Complementary and Alternative Medicine Studies
  • Health Sciences › Medicine › Geriatrics and Gerontology › Pharmaceutical Practices and Patient Outcomes
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutrition and Health Studies
Keywords
herb-drug interactions, drug-supplement interactions, polypharmacy, older adults, herbal medicinal products, dietary supplements, prescription drugs, prevalence, adverse drug interactions, cod liver oil, glucosamine, vitamin D, general practice
MeSH terms
Systematic Reviews as Topic, Aged, Cross-Sectional Studies, Drug Interactions, Drug Therapy, Combination, England, Female, Humans, Health Knowledge, Attitudes, Practice, Male, Phytotherapy, Surveys and Questionnaires, Prevalence, Polypharmacy, Dietary Supplements, Plant Preparations, Prescription Drugs

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