Keywords
codeine, general practice, addiction, dependence
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Ravichandran N, Murphy N, Broughan J et al. Codeine Use in Irish General Practice: A Mixed-Methods Study Protocol on Prescribing, Dependence, and Management of Habit-Forming Use [version 1; peer review: awaiting peer review]. HRB Open Res 2026, 9:77 (https://doi.org/10.12688/hrbopenres.14500.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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Study Protocol
Codeine Use in Irish General Practice: A Mixed-Methods Study Protocol on Prescribing, Dependence, and Management of Habit-Forming Use
[version 1; peer review: awaiting peer review]
PUBLISHED 15 Jul 2026
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Abstract
Corresponding author:
Nandakumar Ravichandran
Competing interests:
No competing interests were disclosed.
Grant information:
The author(s) declared that no grants were involved in supporting this work.
Copyright:
© 2026 Ravichandran N et al.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
How to cite: Ravichandran N, Murphy N, Broughan J et al. Codeine Use in Irish General Practice: A Mixed-Methods Study Protocol on Prescribing, Dependence, and Management of Habit-Forming Use [version 1; peer review: awaiting peer review]. HRB Open Res 2026, 9:77 (https://doi.org/10.12688/hrbopenres.14500.1)
First published: 15 Jul 2026, 9:77 (https://doi.org/10.12688/hrbopenres.14500.1)
Latest published: 15 Jul 2026, 9:77 (https://doi.org/10.12688/hrbopenres.14500.1)
Introduction
Codeine is an opioid analgesic commonly prescribed or sought by patients for its analgesic, antidiarrhoeal, and antitussive effects.1 However, codeine use and the development of iatrogenic (medically induced) dependence have become a growing public health concern worldwide.2,3 Recent studies indicate that Ireland has one of the highest rates of codeine consumption globally, with approximately 30 mean dosage units sold over the counter (OTC) per person.4 In Ireland and the UK, the self-reported prevalence of codeine dependence among regular users is 17%.2 Despite this high level of morbidity, individuals presenting for formal treatment of codeine dependence represent only 2% of those attending addiction services in the Republic of Ireland.5,6 This disparity suggests that codeine dependence in Ireland may be both underdiagnosed and undertreated within primary care.
Several factors contribute to this hidden clinical burden. A primary driver is the relative ease with which low-dose codeine products can be obtained OTC.7,8 This accessibility allows habit-forming, problematic use to remain concealed from a patient’s primary care team until severe complications arise.7,8 Crucially, the clinical harm of this dependence is frequently compounded by the toxicity of combination products.9 Regular users often ingest massive, unsafe doses of companion medications like paracetamol or ibuprofen. For general practice, this manifests as severe, life-threatening pathologies, including gastrointestinal ulceration or perforation, severe hypokalaemia, renal failure, and acute hepatotoxicity.10 While patients often view OTC codeine as safe, the hidden consumption of companion NSAIDs or paracetamol creates a high risk of organ failure long before opioid-seeking behaviour is overtly recognised by a GP.11
Regulatory updates are likely to reshape the landscape of codeine availability.12 The Health Products Regulatory Authority (HPRA) in Ireland initiated a formal regulatory review of OTC medicines containing codeine.13 While several European countries (e.g., Germany, Sweden, Italy) restrict codeine to prescription-only status,14 low-dose formulations remain available OTC in Ireland.15 If Ireland shifts to a prescription-only model, a sharp influx of patients presenting to general practice for pain management, undetected dependence, and deprescribing support is anticipated, as GPs represent the primary gatekeepers of healthcare in Ireland.16,17
Despite these impending pressures, clinical guidelines for identifying, managing, and deprescribing codeine within general practice remain sparse.16 Research by Foley et al. highlighted that medical professionals believe codeine prescribing is rising in response to patient demand, yet 88% noted that patients remain entirely unaware of dependence risks. Furthermore, only 21% of GPs felt confident identifying codeine dependence when a patient does not explicitly disclose it, and just 11% reported having adequate screening protocols in general practice.18
Socioeconomic data also demonstrates that codeine use is highest in areas characterised by lower-income households, rural populations, and physically demanding manual labour industries.19 These geographic and occupational factors suggest that structural vulnerabilities heavily influence patterns of use. Given this evolving regulatory context and the limited infrastructure within primary care, there is an urgent need to evaluate both GP and patient perspectives on prevention, holistic prescribing, and structured deprescribing. This study utilises a mixed-methods approach to address these gaps and inform clinical practice and primary care policy in Ireland.
Methodology
Research design and theoretical framework
This study will adopt a mixed-methods design incorporating:
a. Secondary analysis of Primary Care Reimbursement Service (PCRS) prescribing data will be undertaken to track temporal trends in codeine prescribing expenditure, primary care prescribing rates, and dosage patterns across Irish general practice.
b. A scoping review of existing clinical guidelines and consensus statements on codeine prescribing, management of iatrogenic dependence, and safe deprescribing frameworks within general practice.
c. A quantitative survey of patients attending general practice settings examining self-reported codeine use, dependence patterns, socioeconomic factors, awareness of associated risks, and concurrent consumption of combination ingredients (ibuprofen/paracetamol).
d. In-depth qualitative interviews with a purposive sample of primary care patients using OTC and prescribed codeine to capture lived experiences of iatrogenic dependence and barriers to seeking help from their GP; and
e. Focus groups with practicing GPs exploring clinical prescribing behaviours, methods for detecting hidden codeine dependence, and the management of medical complications stemming from combination product toxicity.
A pragmatic realist theoretical framework will underpin the study. Pragmatism supports the use of mixed methods approaches to capture a comprehensive and dynamic understanding of complex healthcare phenomena.20 Given the multifactorial nature of codeine dependence, including biological, psychological, social, and structural influences, a realist perspective is appropriate to explore the mechanisms underpinning codeine use and dependence, as well as the contextual factors influencing outcomes.20 This approach facilitates examination of the perspectives of multiple stakeholders, including patients and healthcare professionals, within real-world primary care settings. The study design and reporting will also be informed by the Standards for Reporting Qualitative Research (SRQR) framework.21
Setting, participants and sampling
The study will involve anonymous online surveys of patients attending general practices (approximately n = 100), in-depth interviews of patients using medications containing codeine (approximately n = 15–20) and three to four focus groups of general practitioners consisting of approximately 5–7 participants each. Participants will be recruited from general practice networks across the Republic of Ireland. Research suggests these sample sizes are sufficient to achieve data saturation which will be considered when reaching the point where further data collection becomes ‘counter-productive’, and where the ‘new’ does not necessarily add anything to the overall study or theory.22 Data collection for surveys, interviews, and focus groups will primarily occur online using secure videoconferencing platforms such as Zoom.
Inclusion criteria
Patient inclusion criteria
Participants must:
• Aged 18 years or older
• Reside in the Republic of Ireland
• Be currently using or have previously used codeine-containing medication in the past one year (prescribed or OTC sourced)
• Have capacity to provide informed consent
General practitioner inclusion criteria
Participants must:
Data collection and analysis
Scoping review
A scoping review will be conducted between August and October 2026 examining prescribing practices and management approaches for codeine dependence in general practice. Guidelines and consensus statements published between 2010 and 2026 will be identified through searches of four databases (PubMed, Embase, Scopus, Web of Science), search engine google scholar and guideline repositories (TRIP, SIGN, GIN). The review will follow the Arksey and O’Malley framework alongside Joanna Briggs Institute guidance for scoping reviews.23–25 Reporting will adhere to the PRISMA-ScR guidelines.26 Narrative synthesis will be undertaken following the framework proposed by Popay et al.27
Secondary data analysis
Secondary data analysis of aggregated PCRS prescribing data from 2016–2026 will be analysed descriptively to identify temporal trends and regional variation in prescribing practices, to estimate trends in codeine prescribing expenditure, prescribing rates, and dosage patterns within Irish general practice. Descriptive statistics, chi square tests and temporal analyses will be carried out in IBM SPSS.
Surveys, patient interviews and GP focus groups
Recruitment posters and study flyers containing QR codes linking to the anonymous survey will be distributed to general practices throughout Ireland through the professional networks of the UCD School of Medicine and the UCD/HSE Dublin and South-East GP Research Network.
Surveys will be distributed from July 2026 onwards. At the end of the survey, participants will be invited to express interest in participating in follow-up qualitative interviews. Informed consent will be obtained from participants before participating in the interview. Only consented individuals will take part in interviews and focus groups. Interviews and focus groups will be audio-recorded with participant consent. Transcripts will be pseudonymised by removing all identifiable information, including names and addresses. Any identifying data required for study administration will be stored separately in encrypted files accessible only to the principal investigator. Qualitative analysis will be conducted independently by two reviewers (NR and JB), with disagreements resolved through discussion with a third reviewer (WC). Analysis will adopt a pragmatic realist perspective and will also incorporate Braun and Clarke’s Reflexive Thematic Analysis using NVivo software.28 Quantitative survey data will be analysed using descriptive statistical methods in IBM SPSS.
To enhance the validity, credibility, and richness of findings, a triangulation approach will be employed to integrate qualitative and quantitative data. Findings from interviews and focus groups will be compared with survey findings to identify areas of convergence, complementarity, and divergence.29 Qualitative findings will help contextualise and explain quantitative patterns, particularly regarding patient motivations, experiences of dependence, and barriers to help-seeking. Integration of findings will be guided by the realist framework to better understand the contextual mechanisms influencing codeine prescribing, use, dependence, and management within Irish general practice.
Discussion
Codeine dependence remains a severely under-recognised public health and clinical issue within Irish general practice.16 This proposed study seeks to address significant gaps in understanding regarding patient experiences, prescribing practices, awareness of dependence, and barriers to management within general practice settings.
The strength of this study is its mixed-methods design, which enables both quantitative assessment of codeine use patterns and qualitative exploration of patient and GP experiences.30 The inclusion of multiple stakeholder perspectives may provide a more comprehensive understanding of the contextual and behavioural factors influencing codeine prescribing and dependence in Ireland.
The study is particularly timely given the ongoing HPRA review of OTC codeine products and the possibility of future regulatory changes. If codeine becomes prescription-only in Ireland, general practice services may experience increased patient presentations relating to pain management, codeine dependence, and deprescribing support. Findings from this research may therefore help inform future prescribing guidance, educational interventions, screening protocols, and policy development within Irish primary care.
The study may also identify important socioeconomic and structural determinants associated with codeine use, including deprivation, rurality, and occupational factors in the context of Irish general practice.31 Understanding these influences may support the development of more targeted and equitable public health strategies. The findings of this study will inform clinical trial interventions in treating codeine dependence in Irish general practice.
Triangulation of qualitative and quantitative findings is expected to strengthen the validity and depth of the study conclusions. Overall, this study has the potential to contribute meaningful evidence regarding codeine dependence in Ireland and support the development of holistic, patient-centred approaches to prescribing, monitoring, and deprescribing codeine within general practice.
Ethical considerations
Ethical approval will be obtained from the University College Dublin Human Research Ethics Committee. The study will be conducted in accordance with the principles of the Declaration of Helsinki and will comply with all applicable data protection regulations, including the General Data Protection Regulation (GDPR).
Participation in the survey will be anonymous. Interview and focus group data will be pseudonymised prior to analysis. All study data will be stored securely in encrypted databases and managed in accordance with institutional data protection and data management policies. All participants will receive a Participant Information Leaflet outlining the purpose, procedures, risks, benefits, and confidentiality arrangements of the study. Written informed consent will be obtained from all participants prior to their participation in the interviews and focus groups. Participation is voluntary, and participants will be informed of their right to withdraw from the study at any time without affecting their care or relationship.
Data management
The data controller of the study is the UCD School of Medicine. The safety of all data will be ensured by (1) applying encrypted password-protected code to all transcripts; (2) storing all data in an encrypted database for up to 5 years and only being accessible by the research team; (3) storing all personal identifying information of participants separately from all study datasets and allocating each participant with a unique participant identification number to delink the information from the personal identifiers; and (4) destroying all audio recordings on completion of transcription. Only anonymised participants’ data will be shared during routine updates and briefing sessions.
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Ravichandran N, Murphy N, Broughan J et al. Codeine Use in Irish General Practice: A Mixed-Methods Study Protocol on Prescribing, Dependence, and Management of Habit-Forming Use [version 1; peer review: awaiting peer review]. HRB Open Res 2026, 9:77 (https://doi.org/10.12688/hrbopenres.14500.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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