New options for opioid-induced constipation in Australian hospitals

At Hospital Medicine 2017, organised by the Society of Hospital Medicine and held from 1–4 May at Mandalay Bay Resort and Casino in Las Vegas, hospitalists and other healthcare professionals gathered to discuss research, clinical practice and innovations in patient care. The programme included continuing medical education, learning resources and opportunities for professional networking. Among the practical clinical issues considered was the management of opioid-induced constipation, where newer medicines were emerging alongside better approaches to assessment and treatment. Learn more about Practical Approaches To Managing Non Nutritive Sweeteners On Hospital Diets Hm17 Session.

For Australian clinicians, this topic carries particular relevance because opioid prescribing is common in acute pain, palliative care, cancer treatment and chronic pain services. The challenge is not simply prescribing a laxative, but identifying patients at risk, choosing a regimen suited to their illness and making sure treatment continues after discharge. Australian hospitals also need to navigate differences between medicines approved by the Therapeutic Goods Administration, outpatient subsidy through the Pharmaceutical Benefits Scheme and availability through individual hospital formularies.

Why opioid-related bowel change matters

Opioids affect bowel function through several mechanisms. They slow gastrointestinal motility, increase fluid absorption within the bowel and alter the coordination of defecation. Patients may therefore develop hard stools, straining, abdominal bloating and a sensation of incomplete emptying even when their fluid intake is adequate. Opioid-induced constipation is distinct from constipation caused by dehydration alone, which means adding water or fibre may not resolve it.

The consequences can extend beyond discomfort. Severe constipation may lead to faecal impaction, overflow diarrhoea, nausea, abdominal distension and delirium. A distended bowel can also make pain and respiratory observations more difficult to interpret. Patients may require higher opioid doses to achieve comfortable pain control, creating a cycle in which constipation worsens and analgesia is escalated unnecessarily.

The Hospital Medicine 2017 discussion placed this problem within routine hospital medicine rather than treating it as a minor digestive complaint. A reliable approach combines bowel assessment with a prescribing protocol and clear escalation criteria. That matters on busy wards in Melbourne, Brisbane and Sydney, as well as in regional hospitals, where medical teams may cover several services and patients can move between acute, surgical and rehabilitation care.

Assess the patient before choosing a treatment

A useful bowel history should establish the patient’s normal pattern, when symptoms began in relation to opioid therapy and whether there is pain, vomiting, bloating or visible distension. Ask about medicines that may compound constipation, including anticholinergics, calcium-channel blockers, iron, antiemetics and some antidepressants. Diet and fluid history can be relevant, but they should not distract from the opioid effect or suggest that constipation is automatically due to poor intake.

Medication reconciliation provides a practical starting point. In Australian services this may involve a paper medication chart, including the National Inpatient Medication Chart used in some hospitals, or an electronic medication record. Opioids such as morphine, oxycodone and fentanyl patches may have been started elsewhere, making the timing and intended duration of treatment important. Patients should also be asked about laxatives already used at home, since a familiar regimen may be safer and more acceptable than an unfamiliar product.

Physical examination is guided by symptoms and consent. Abdominal inspection and palpation can identify distension or tenderness, while a rectal assessment may be appropriate when impaction is suspected. Faecal overflow can resemble diarrhoea, so liquid stool does not always exclude serious constipation. Severe pain, absent bowel sounds, persistent vomiting, feculent breath or the absence of flatus requires prompt medical review for obstruction or ileus. Clear escalation criteria are familiar from other inpatient deterioration work: a companion review of rapidly escalating oxygen needs shows how predefined thresholds can prevent delays in urgent treatment.

Build a simple ward protocol

A ward protocol should start with prevention. Opioid-induced constipation can appear soon after treatment begins, so waiting for a patient to become severely symptomatic is avoidable. The protocol should specify when assessment occurs, which oral regimen is preferred, how response is reviewed and what triggers rectal treatment or senior review. A measurable goal such as comfortable, formed stools is usually more useful than insisting on a bowel movement every day.

For most patients without obstruction or impaction, polyethylene glycol or macrogol is a reasonable first-line oral treatment. It is generally well tolerated and has stronger evidence than many traditional alternatives. A stimulant laxative such as senna can be added when onset is insufficient or symptoms are more pronounced. Bisacodyl provides another oral option, while a suppository or mini-enema may be needed when stool is in the distal bowel and oral treatment is unlikely to work promptly.

Bulk-forming fibre and large volumes of fluid are not suitable for every patient. They can worsen distension in slow transit or obstruction, while increased fluid may be inappropriate in patients with heart failure, renal impairment or strict fluid restrictions. Lactulose may produce considerable gas and is often less convenient than macrogol in an acute setting. The protocol should make these limitations explicit rather than leaving every choice to individual habit.

Monitoring belongs in the same system as medication administration. A bowel chart can record stool consistency, frequency, abdominal symptoms and the effect of treatment without flooding the record with every detail. Review should occur after initiation and whenever opioid dose changes. If symptoms persist despite an adequate regimen, clinicians should reconsider impaction, obstruction, alternative medicines and the original opioid before escalating indefinitely.

Where newer medicines fit

The options discussed around the Hospital Medicine 2017 meeting broadened the range beyond stimulant and osmotic laxatives. Agents such as lubiprostone, plecanatide and naldemedine act through mechanisms that differ from ordinary bowel-stimulating laxatives. Lubiprostone and plecanatide promote intestinal fluid secretion, while naldemedine blocks opioid receptors in the periphery without producing the central opioid antagonism associated with naloxone.

These medicines are most relevant when constipation remains troublesome despite an established regimen. Plecanatide and naldemedine had demonstrated benefits in clinical trials, although much of the evidence came from ambulatory patients rather than acutely unwell hospital admissions. Their place in inpatient care therefore depends on local protocols and individual clinical assessment. A medicine that works well over several weeks may be less suitable when rapid relief is required within a shift.

Australian access requires particular attention. TGA approval determines whether a product may be marketed, PBS listing influences subsidised outpatient use, and hospital formularies determine which medicines can be prescribed without individual approval. Availability may differ between metropolitan and regional services. Newer products may also cost more, creating a need to balance the treatment burden of constipation with the expense and workload of repeated rescue measures.

Prescribers must review contraindications, adverse effects and interactions. Diarrhoea is common with several of these agents and can complicate an inpatient stay. Naldemedine requires care in patients with gastrointestinal obstruction and in those whose opioid dependence could be affected by opioid antagonism. These products should not be used as an automatic response to an unassessed bowel, because a patient with impaction or obstruction may need a different immediate plan.

Support recovery beyond the laxative

Medication remains central, but practical measures can improve the chance that treatment succeeds. Offer regular access to the toilet, maintain privacy and avoid unnecessary bed rest where mobility is safe. Encourage patients to respond to the urge to defecate rather than delaying because they are waiting for observations, transport or tests. Constipation can be particularly difficult to discuss, and Australian patients may simply describe being “blocked up” rather than using the clinical term.

Food and drink preferences can influence intake, although dietary measures rarely replace drug therapy in established opioid-induced constipation. A Hospital Medicine 2017 review of non-nutritive sweeteners illustrates how hospital diet teams translate evidence into manageable choices. The same principle applies to bowel care: recommendations should be realistic for the ward environment and respectful of cultural preferences, religious practices and the resources available at home.

Communication should also account for language and family support. Aboriginal and Torres Strait Islander patients may benefit from culturally safe services, interpreter support and involvement of family members when consent and preferences allow it. The aim is not to assume causes based on identity, but to avoid treating bowel symptoms as an embarrassing nuisance. In palliative care, goals may differ again, with comfort and the patient’s wishes taking priority over a standard bowel target.

Discharge planning should include what was prescribed, when it is expected to work and which symptoms require reassessment. Patients need access to a suitable laxative and an opioid plan that is coordinated with their bowel regimen. General practitioners, community palliative services and aged-care teams should understand the intended approach, particularly when the hospital has used a newer agent that is not routinely stocked in the community.

A practical plan for the next ward shift

Choosing between laxatives is less difficult when each option is matched to a clear clinical purpose. The regimen should move from simple oral prevention to targeted treatment, with a documented route for escalation and review.

A usable protocol should name the preferred oral agent, specify assessment and review points, and state when rectal treatment or medical review is required. It should also distinguish between prevention, treatment of established constipation and urgent assessment for possible obstruction. Local agreement is important because opioid medicines, laxative preparations and formularies differ across Australian health services.

The conference value of newer options is that they give clinicians additional choices when a basic regimen fails, but they do not replace careful assessment or a straightforward ward pathway. Teams should retain a simple first-line regimen, reserve specialist medicines for appropriate patients and document the plan clearly. The practical takeaway is to treat opioid-induced constipation as a monitored part of opioid care: identify risk early, use an evidence-based regimen, escalate safely when needed and ensure continuity after discharge.