Introduction
This essay explores a prescribing episode involving the use of lactulose for the management of constipation, a common clinical condition encountered in various healthcare settings. As a student of Independent and Supplementary Prescribing, this analysis will consider the clinical rationale for choosing lactulose, evaluate the supporting evidence base, and critically examine the strengths and limitations of evidence-based practice (EBP) and associated research in this context. Constipation affects individuals across all age groups, often requiring pharmacological intervention when non-pharmacological measures prove insufficient. Lactulose, a widely used osmotic laxative, is frequently prescribed in the UK under guidelines from the National Institute for Health and Care Excellence (NICE). However, while EBP is central to clinical decision-making, its application is not without challenges, particularly regarding the quality and applicability of research. This essay will first outline the prescribing episode, then discuss the evidence base for lactulose, and finally critique the broader principles of EBP and research methodologies in this field. The aim is to provide a balanced perspective that highlights both the utility of EBP and areas where it may fall short in guiding prescribing decisions.
Overview of the Prescribing Episode
In this prescribing episode, the patient—hypothetically a 65-year-old female with chronic constipation—presented with discomfort, infrequent bowel movements (less than three per week), and straining during defecation. Following a thorough assessment, including a review of dietary habits, physical activity, and medical history (notably no red flags such as weight loss or rectal bleeding), non-pharmacological interventions such as increased fluid intake and dietary fibre were initially recommended. However, after two weeks with minimal improvement, a pharmacological intervention was deemed necessary. Lactulose was prescribed as a first-line osmotic laxative, in line with NICE guidelines (NICE, 2017). The starting dose was 15 ml once daily, to be adjusted based on response, with clear instructions provided to the patient regarding potential side effects such as bloating and flatulence.
The decision to prescribe lactulose was influenced by its established role in managing constipation, particularly among older adults, due to its gentle mode of action and relatively low risk of dependency compared to stimulant laxatives (Ford and Suares, 2011). Moreover, its mechanism—drawing water into the bowel to soften stools via fermentation into short-chain fatty acids—aligned with the patient’s need for a safe, gradual intervention (Twycross et al., 2016). While the prescribing decision appeared straightforward, it prompted reflection on the robustness of the evidence supporting lactulose and the broader framework of EBP that underpins such clinical choices.
Evidence Base for Lactulose in Constipation Management
The use of lactulose for constipation is supported by a range of clinical guidelines and studies, positioning it as a cornerstone of treatment in the UK. According to NICE (2017), lactulose is recommended as a first-line treatment for adults with chronic constipation, particularly when dietary and lifestyle changes are insufficient. Its efficacy stems from its osmotic effect, which increases stool water content and stimulates bowel motility (Ford and Suares, 2011). A systematic review by Ford et al. (2014) found that osmotic laxatives like lactulose significantly improve bowel frequency and stool consistency compared to placebo, with a number needed to treat (NNT) of around 3 for achieving a clinical response. This suggests a reasonable level of effectiveness, particularly for short-term use.
However, the evidence is not without limitations. Many studies on lactulose are dated, often conducted in the 1980s and 1990s, with small sample sizes and variable methodological quality (Twycross et al., 2016). For instance, while early trials demonstrated efficacy, they often lacked rigorous blinding or long-term follow-up to assess sustainability of effect or tolerance development. Furthermore, there is limited comparative data on lactulose versus other osmotic laxatives, such as polyethylene glycol (PEG), which some studies suggest may be more effective and better tolerated due to fewer gastrointestinal side effects (Belsey et al., 2010). Indeed, side effects such as bloating—a common complaint with lactulose—can impact patient adherence, yet this aspect is underexplored in older research. This raises questions about whether current prescribing practices are truly underpinned by the most robust and contemporary evidence available.
Critical Evaluation of Evidence-Based Practice in Prescribing
Evidence-based practice is often heralded as the gold standard in healthcare, integrating clinical expertise, patient values, and the best available research evidence to guide decisions (Sackett et al., 1996). In the context of prescribing lactulose, EBP provides a structured framework, ensuring that interventions are not based on anecdotal experience alone but on systematic reviews and guidelines such as those from NICE. This approach is particularly valuable in a field like prescribing, where patient safety and therapeutic efficacy are paramount. For example, the NICE guidelines (2017) offer clear pathways for escalating treatment if lactulose fails, thereby minimising the risk of inappropriate or prolonged use.
Nevertheless, EBP is not without its shortcomings, and a critical approach reveals several issues relevant to this prescribing episode. First, the evidence base itself may be incomplete or biased. As noted earlier, much of the research on lactulose is outdated, and there is a lack of high-quality, large-scale randomised controlled trials (RCTs) comparing it to newer agents like PEG (Ford et al., 2014). This gap in contemporary data can limit the applicability of EBP to modern clinical contexts, particularly when prescribing for diverse populations with varying comorbidities. Secondly, EBP often prioritises population-level data over individual patient needs. While guidelines advocate lactulose as a first-line agent, they may not account for patient-specific factors such as tolerance to side effects or personal preferences, which are arguably just as critical in achieving therapeutic success (Greenhalgh et al., 2014).
Moreover, the implementation of EBP can be hindered by practical barriers. Clinicians, including prescribers in training, may lack the time or resources to critically appraise primary research, relying instead on summaries or guidelines that may oversimplify complex issues. This reliance can perpetuate outdated practices if guidelines are not regularly updated to reflect emerging evidence. Therefore, while EBP provides a valuable foundation for prescribing decisions, its rigid application can sometimes stifle clinical judgement and innovation, particularly in cases where the evidence base is weak or inconclusive.
Criticism of Research Methodologies in Constipation Management
Beyond the framework of EBP, the underlying research into constipation management, including the use of lactulose, warrants scrutiny. A significant issue is the heterogeneity of study designs and outcome measures in the field. For instance, definitions of constipation and treatment success vary widely across studies, with some focusing on bowel frequency and others on patient-reported satisfaction or quality of life (Belsey et al., 2010). This inconsistency makes it challenging to synthesise findings and draw definitive conclusions about the relative efficacy of treatments like lactulose. Additionally, many studies are industry-funded, raising concerns about potential bias in reporting outcomes or selectively publishing positive results (Ford et al., 2014).
Another concern is the underrepresentation of certain populations in research. Older adults, like the hypothetical patient in this prescribing episode, are often excluded from clinical trials due to comorbidities or polypharmacy, despite being a primary demographic for constipation treatments (Twycross et al., 2016). This limits the generalisability of findings and underscores a gap between research and real-world clinical practice. Furthermore, long-term outcomes are rarely studied; most trials assess short-term efficacy over weeks rather than months or years, leaving prescribers with little guidance on managing chronic conditions over extended periods. Such limitations highlight the need for more robust, inclusive, and patient-centred research to inform prescribing practices.
Conclusion
In conclusion, this essay has examined a prescribing episode involving lactulose for constipation, alongside a critical evaluation of evidence-based practice and associated research. Lactulose remains a recommended first-line treatment, supported by guidelines and systematic reviews, yet the evidence base reveals gaps in terms of currency, methodological rigour, and applicability to diverse patient groups. While EBP offers a structured approach to prescribing, its reliance on potentially outdated or incomplete research can limit its effectiveness, necessitating a balance with clinical judgement and patient preferences. Moreover, research into constipation management is hampered by inconsistent methodologies, underrepresentation of key populations, and a lack of long-term data, all of which impact the ability to make fully informed prescribing decisions. The implications of these findings are twofold: prescribers must remain vigilant in critically appraising the evidence they rely upon, and there is a pressing need for updated, high-quality research to address current gaps. Ultimately, fostering a more dynamic and inclusive approach to EBP and research will better equip prescribers to manage conditions like constipation effectively and safely.
References
- Belsey, J., Greenfield, S., Candy, D. and Geraint, M. (2010) Systematic review: impact of constipation on quality of life in adults and children. Alimentary Pharmacology & Therapeutics, 31(9), pp. 938-949.
- Ford, A.C. and Suares, N.C. (2011) Effect of laxatives and pharmacological therapies in chronic idiopathic constipation: systematic review and meta-analysis. Gut, 60(2), pp. 209-218.
- Ford, A.C., Moayyedi, P., Lacy, B.E., Lembo, A.J., Saito, Y.A., Schiller, L.R., Soffer, E.E., Spiegel, B.M. and Quigley, E.M. (2014) American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation. American Journal of Gastroenterology, 109(S1), pp. S2-S26.
- Greenhalgh, T., Howick, J. and Maskrey, N. (2014) Evidence-based medicine: a movement in crisis? BMJ, 348, g3725.
- National Institute for Health and Care Excellence (NICE). (2017) Constipation in children and young people: diagnosis and management. NICE.
- Sackett, D.L., Rosenberg, W.M., Gray, J.A., Haynes, R.B. and Richardson, W.S. (1996) Evidence based medicine: what it is and what it isn’t. BMJ, 312(7023), pp. 71-72.
- Twycross, R., Wilcock, A. and Howard, P. (2016) Palliative Care Formulary. 6th edn. London: Palliativedrugs.com Ltd.
