Intended for healthcare professionals


Cannabis based drugs: GPs will have to manage patients’ expectations, says expert

BMJ 2018; 363 doi: (Published 16 October 2018) Cite this as: BMJ 2018;363:k4354

Re: Cannabis based drugs: GPs will have to manage patients’ expectations, says expert

We read with interest the words of Ian Hamilton, quoted in Gareth Iacobucci’s article 1. Mr Hamilton advises GPs without specialist knowledge of the evidence for medicinal cannabis to discuss with colleagues in their team and to use Google Scholar to resolve uncertainties, until such as time as NHS England and the National Institute for Health and Clinical Excellence produce guidance

We acknowledge that the evidence for medicinal cannabis in a number of conditions is unclear, but it does exist and is discoverable, for example, a recent Cochrane review of cannabis‐based medicines for chronic neuropathic pain 2, and evidence summaries in point of care tools such as DynaMed Plus3.

While Google Scholar is an admirable and innovative resource, any one search tool, whether bibliographic database, search engine, or hybrid, will only give a partial view of the literature. We would suggest that there is a better and more efficient way to fill knowledge gaps: to use the services of an expert in evidence synthesis and appraisal, a librarian. In doing so, clinicians can save time, and be assured that literature from multiple sources has been brought together into a comprehensive and reliable view of the current state of knowledge. A 2016 study of clinical librarians’ impact on patients and health care organisations4 found positive effects on continuing professional development (CPD), decision making and evidence-based practice. These could be helpful for a GP whose specialist knowledge of medicinal cannabis, as Hamilton notes, may be limited. In addition, many health librarians are experts in teaching critical appraisal, a crucial skill when searching and reading the literature.

Librarians may be found in NHS Library and Knowledge Services, Royal Colleges and other membership organisations, and in higher education. While local access arrangements vary within England, primary care and community NHS staff in Wales and Scotland can access both online resources and physical library stock. All HSC staff in Northern Ireland (including primary and secondary care) are eligible to access online resources and physical library stock, as well as advice and support from specialist librarians. We recommend GPs or other NHS staff based in England contact their local hospital to discover what access they have to library resources: services may be located using the Health Library and Information Services Directory (HLISD)5 website is searchable by location so staff can find their nearest service. We are aware that access to library services may be uneven across the UK; we believe this presents an opportunity to resolve this issue, and for the information profession and other interested bodies such as the Royal College of General Practitioners (RCGP) to work more closely towards solutions.

We would urge any health professional who needs a succinct usable summary of current evidence to ask a librarian.

The authors work as librarians in the NHS and higher education

1 Iacobucci Gareth. Cannabis based drugs: GPs will have to manage patients’ expectations, says expert BMJ 2018; 363 :k4354

2 Mücke M, Phillips T, Radbruch L, Petzke F, Häuser W. Cannabis‐based medicines for chronic neuropathic pain in adults. Cochrane Database of Systematic Reviews 2018, Issue 3. Art. No.: CD012182. DOI: 10.1002/14651858.CD012182.pub2.

3 DynaMed Plus [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. 901291, Medical uses of cannabinoids; [updated 2018 Aug 22]; [about 33 screens]. Available from Registration and login required.

4 Brettle A, Maden M, Payne C. The impact of clinical librarian services on patients and health care organisations. Health Information and Libraries Journal [internet]. 2016 Feb 17 [cited 2018 Oct 22]; 33(2): 100-120. Available from: doi:

5 Health Library and Information Services Directory (HLISD). [Internet] 2018 [cited 2018 Oct 22]; [50+ screens]. Available from:

Competing interests: No competing interests

23 October 2018
Tom C Roper
Clinical Librarian
Annette Thain, NHS Education for Scotland Sarah Bruch, Prince Philip Hospital Library Manager, Hywel Dda University Health Board Kerry Flett, Librarian, Portsmouth Hospitals NHS Trust Library and eLearning Services Hannah Shakespeare, Deputy and Outreach Librarian, Worcestershire Health Libraries, Worcestershire Acute NHS Trust Keith Nockels, Academic Librarian, University of Leicester Jane O’Neill, Medical and Healthcare Librarian, the Healthcare Library of Northern Ireland and Queen’s University Medical Library
Brighton and Sussex NHS Library and Knowledge Service
Brighton, UK