Trulicity (dulaglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist widely prescribed in the UK for type 2 diabetes management. Whilst effective for glycaemic control, can Trulicity cause severe constipation? Constipation is a recognised side effect, affecting up to 1 in 10 patients, primarily due to slowed gastric emptying and reduced gastrointestinal motility. Most cases are mild to moderate and resolve within weeks, but severe constipation can occur in a small proportion of patients, potentially leading to complications such as faecal impaction. Understanding this risk, implementing preventative strategies, and recognising when to seek medical advice are essential for safe and effective diabetes management.

Can Trulicity Cause Severe Constipation?

Trulicity (dulaglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for the treatment of type 2 diabetes mellitus. It works by mimicking the action of the naturally occurring hormone GLP-1, which stimulates insulin secretion, suppresses glucagon release, and slows gastric emptying. This slowed gastric emptying contributes to both its glucose-lowering effect and gastrointestinal side effects.

Constipation is a recognised adverse effect of Trulicity, though it is generally less common than nausea or diarrhoea. According to the Summary of Product Characteristics (SmPC), constipation is common (may affect up to 1 in 10 people) in patients taking dulaglutide. The mechanism involves the slowing of gastrointestinal motility, which can reduce bowel frequency and lead to harder stools. Most cases are mild to moderate in severity and tend to improve as the body adjusts to the medication, typically within the first few weeks of treatment.

However, severe constipation can occur in a small proportion of patients. Severe cases may present with significant abdominal discomfort, bloating, straining, or infrequent bowel movements (fewer than three per week). In rare instances, prolonged constipation can lead to complications such as faecal impaction or bowel obstruction, particularly in vulnerable individuals with pre-existing gastrointestinal conditions or reduced mobility. It is important to note that Trulicity is not recommended in patients with severe gastrointestinal disease (such as severe gastroparesis).

If gastrointestinal symptoms are troublesome, your healthcare provider may consider delaying dose escalation or reducing to the last tolerated dose. Patients should be counselled about this potential side effect when initiating Trulicity and advised on preventative measures and when to seek further advice.

Managing Constipation While Taking Trulicity

Effective management of constipation associated with Trulicity involves a combination of lifestyle modifications, dietary adjustments, and, when necessary, pharmacological interventions. Early implementation of these strategies can prevent progression to more severe symptoms and improve treatment adherence.

Dietary and lifestyle measures form the foundation of constipation management:

• Increase dietary fibre intake gradually to 25–30 grams daily through wholegrain cereals, fruits, vegetables, pulses, and legumes. Consider soluble fibre options, which may be better tolerated. Fibre adds bulk to stools and promotes regular bowel movements, but increasing too quickly can worsen bloating, especially when taking a GLP-1 receptor agonist.

• Maintain adequate hydration by drinking 1.5–2 litres of water daily, unless contraindicated by other medical conditions. Adequate fluid intake softens stools and facilitates passage.

• Engage in regular physical activity, such as 30 minutes of moderate exercise most days of the week. Physical activity stimulates intestinal motility and can significantly improve bowel function.

• Establish a regular bowel routine by responding promptly to the urge to defecate and allowing sufficient time without rushing.

Pharmacological options may be considered if lifestyle measures prove insufficient. According to NICE guidance on constipation management:

• Osmotic laxatives (e.g., macrogol) are often first-line for medication-related constipation. They draw water into the bowel, softening stools and increasing frequency.

• Bulk-forming laxatives (e.g., ispaghula husk) may be suitable if stools are small and hard, and fluid intake is adequate. These should be avoided if obstruction is suspected or if the person cannot maintain adequate hydration.

• Stimulant laxatives (e.g., senna, bisacodyl) may be used short-term or longer-term under medical supervision at the lowest effective dose.

Patients should consult their GP or diabetes specialist nurse before starting laxatives to ensure appropriate selection and dosing. A medication review may be helpful to identify other constipating drugs (such as opioids, anticholinergics, or calcium-channel blockers). It is important not to discontinue Trulicity without medical advice, as the benefits for glycaemic control should be considered alongside manageable side effects.

When to Seek Medical Advice About Constipation

Whilst mild constipation can often be managed with self-care measures, certain symptoms warrant prompt medical evaluation. Patients taking Trulicity should be aware of red flag features that may indicate serious underlying complications or the need for treatment adjustment.

Call 999 or go to A&E immediately if you experience:

• Severe abdominal pain that is persistent, worsening, or accompanied by abdominal distension and vomiting, which may suggest bowel obstruction.

• Complete inability to pass stool or wind for more than 48 hours, which may indicate faecal impaction or obstruction.

• Severe, persistent upper abdominal pain radiating to the back, especially with vomiting (possible pancreatitis, a rare but serious side effect of GLP-1 receptor agonists).

Contact your GP urgently or call NHS 111 if you have:

• Rectal bleeding or blood in the stool, particularly if you are aged 50 or over, as this requires investigation to exclude colorectal pathology.

• Unexplained weight loss with abdominal pain, especially if you are aged 40 or over.

• Change in bowel habit lasting more than 6 weeks, particularly if you are aged 60 or over or have iron-deficiency anaemia.

Contact your GP or diabetes care team within a few days if:

• Constipation persists despite lifestyle modifications and over-the-counter laxatives for more than one to two weeks.

• You experience significant changes in bowel habit that differ from your usual pattern.

• Constipation is causing substantial distress or affecting your quality of life.

• You have concerns about continuing Trulicity due to gastrointestinal side effects.

Your healthcare provider may consider dose adjustment, temporary treatment interruption, or switching to an alternative diabetes medication if constipation proves intractable. They will also exclude other contributing factors such as concurrent medications, hypothyroidism, or structural bowel abnormalities. Your GP may recommend a faecal immunochemical test (FIT) to help assess your symptoms according to local pathways. Regular monitoring and open communication with your diabetes team are essential to optimise both glycaemic control and gastrointestinal tolerability.

If you suspect Trulicity has caused constipation or any other side effect, you can report this through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk or the Yellow Card app).

Alternative Treatments If Constipation Persists

If constipation remains problematic despite optimal management strategies, your healthcare team may consider alternative therapeutic options for type 2 diabetes management. The decision to switch medications should balance glycaemic efficacy, cardiovascular benefits, tolerability, and individual patient factors.

Alternative GLP-1 receptor agonists may be considered, as gastrointestinal side effects can vary between agents in this class. Options include:

• Semaglutide (Ozempic, Rybelsus) – available as weekly injection or daily oral formulation. Whilst it shares the same mechanism as Trulicity, some patients tolerate one GLP-1 agonist better than another.

• Liraglutide (Victoza) – a daily injection that may have a different side effect profile for some individuals.

• Exenatide (Byetta, Bydureon) – availability may be limited in some UK formularies; check with your healthcare provider.

It should be noted that all GLP-1 receptor agonists can cause gastrointestinal side effects, including constipation, due to their shared mechanism of action. However, individual responses vary, and a trial of an alternative agent may be worthwhile.

Other diabetes medication classes that do not affect gastrointestinal motility include:

• SGLT2 inhibitors (e.g., dapagliflozin, empagliflozin) – offer cardiovascular and renal benefits with a different mechanism of action and side effect profile.

• DPP-4 inhibitors (e.g., sitagliptin, linagliptin) – generally well-tolerated with minimal gastrointestinal effects. Note that these should not be combined with GLP-1 receptor agonists.

• Metformin – first-line therapy for type 2 diabetes, though it more commonly causes diarrhoea rather than constipation.

• Insulin therapy – may be appropriate for some patients, particularly those with inadequate glycaemic control.

NICE guidelines (NG28) recommend individualised treatment approaches for type 2 diabetes, considering HbA1c targets, comorbidities (particularly cardiovascular and renal disease), kidney function (eGFR), weight management goals, hypoglycaemia risk, and patient preferences. Your diabetes specialist will work with you to identify the most appropriate alternative that maintains glycaemic control whilst minimising adverse effects. Regular follow-up and monitoring are essential when transitioning between diabetes medications to ensure both safety and efficacy.

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