Why does lanreotide (Somatuline) cause diarrhea, and is it temporary?

From the Guidelines

Lanreotide can cause diarrhea as a common side effect due to its alteration of gut motility and secretion patterns, and this side effect is often temporary, improving over time as the body adjusts to the medication. This medication is a somatostatin analog that inhibits various hormones in the digestive tract, which can disrupt normal digestive processes and lead to changes in bowel movements, as noted in the guidelines for the management of gastroenteropancreatic neuroendocrine tumours 1. The exact mechanism involves binding to somatostatin receptor subtypes 2 and 5, which are present in the vast majority of neuroendocrine tumours, thereby inhibiting the release of peptide hormones and potentially impairing some exocrine functions 1.

Some key points to consider about lanreotide-induced diarrhea include:

• The incidence of diarrhea as a side effect of lanreotide and other somatostatin analogues is reported, although specific percentages are not detailed in the provided study 1.
• Management strategies for diarrhea may include dietary modifications, staying hydrated, and potentially using anti-diarrheal medications, although these are not explicitly mentioned in the context of lanreotide in the provided evidence 1.
• The importance of monitoring and reporting significant gastrointestinal symptoms to healthcare providers cannot be overstated, as adjustments to the treatment regimen may be necessary to mitigate side effects while maintaining therapeutic efficacy 1.
• The study highlights that few side effects from somatostatin analogues have been reported, and these include, among others, diarrhea, indicating that while it is a potential side effect, it is part of a broader profile that includes other gastrointestinal and systemic effects 1.

Given the potential for temporary diarrhea as a side effect of lanreotide, it is crucial for patients to be aware of this possibility and to discuss any concerns or symptoms with their healthcare provider, who can offer guidance on managing side effects and adjusting treatment as necessary to optimize both the therapeutic outcome and the patient's quality of life 1.

From the FDA Drug Label

New onset steatorrhea, stool discoloration and loose stools have been reported in patients receiving somatostatin analogs, including lanreotide products Somatostatin analogs reversibly inhibit secretion of pancreatic enzymes and bile acids, which may result in malabsorption of dietary fats and subsequent symptoms of steatorrhea, loose stools, abdominal bloating, and weight loss The most commonly reported adverse reactions reported by greater than 5% of patients who received lanreotide (N=416) in the overall pooled safety studies in acromegaly patients were gastrointestinal disorders (diarrhea, abdominal pain, nausea, constipation, flatulence, vomiting, loose stools)

Lanreotide causes diarrhea due to its effect as a somatostatin analog, which reversibly inhibits secretion of pancreatic enzymes and bile acids, leading to malabsorption of dietary fats and subsequent symptoms of steatorrhea and loose stools.

• The diarrhea is a common adverse reaction, reported by greater than 5% of patients who received lanreotide.
• It is not explicitly stated in the label whether the diarrhea is temporary or not, as the label only mentions that the inhibition of pancreatic enzymes and bile acids is reversible. 2

From the Research

Lanreotide and Diarrhea

• Lanreotide is a somatostatin analogue that can cause diarrhea as a side effect, but the provided studies do not directly address why lanreotide causes diarrhea 3, 4, 5, 6, 7.
• However, it is known that somatostatin analogues can affect gastrointestinal secretions and motility, which may lead to diarrhea 3.
• The studies provided focus on the use of lanreotide and other somatostatin analogues in treating various gastrointestinal conditions, such as chronic idiopathic diarrhea, gastrointestinal angiodysplasias, and chemotherapy-induced diarrhea 3, 4, 5, 6, 7.

Temporariness of Diarrhea

• The temporariness of diarrhea caused by lanreotide is not directly addressed in the provided studies 3, 4, 5, 6, 7.
• However, one study mentions that lanreotide can improve symptoms of chronic idiopathic diarrhea, suggesting that the diarrhea may be temporary or manageable with treatment 3.
• Another study notes that octreotide, a different somatostatin analogue, can resolve severe chemotherapy-induced diarrhea, allowing patients to continue their chemotherapy treatment 5.

Adverse Events

• The studies mention that adverse events, including diarrhea, can occur in patients taking lanreotide or other somatostatin analogues 4, 5, 6, 7.
• The most common adverse events reported in one study include loose stools, cholelithiasis, flatulence, and administration site reactions 4.
• However, the studies also suggest that lanreotide and other somatostatin analogues can be effective and safe in treating various gastrointestinal conditions, with a good safety profile 3, 4, 7.