The most common adverse events are GI related, occurring in 67-84% of patients, and are typically mild to moderate. GI related effects are often transient, improve with subsequent injections, and most frequently include diarrhea and abdominal pain. Other GI symptoms such as nausea, vomiting, and abdominal distension are less common. It is not clear whether or not GI effects are dose related.
Adverse effects relating to site of injection occur in 43% of patients and are more common in patients who self-inject as opposed to those who had health-care professionals administer the injection.
A small number of patients report newly impaired glucose tolerance, fasting glucose or diabetes mellitus. Patients being treated for diabetes mellitus may experience hypoglycemia. After 1 year, up to 30% of patients may experience gallstone formation and the presence of sludge within the gallbladder due to inhibition of gallbladder and GI motility. This may be influenced by previous exposure to somatostatin analogues. Other adverse effects include reduction in left ventricular end-diastolic and end-systolic volumes, bradycardia, nasopharyngitis, and alopecia. Lanreotide is classified as Pregnancy Category C.