Octreotide

How it works

It mimics somatostatin by binding somatostatin receptors to inhibit secretion of growth hormone and numerous gastrointestinal and pancreatic hormones, and reduces splanchnic blood flow.

Prescribing in practice

• Long-term use predisposes to gallstones and biliary sludge, so gallbladder surveillance is advised; it can also alter glucose homeostasis in either direction.
• It may cause bradycardia and conduction changes, and abrupt cessation in acromegaly or carcinoid can lead to rebound symptoms.
• Doses of concomitant antidiabetic and other drugs may need adjustment because of its broad inhibitory hormonal effects.

Monitoring

Monitor the relevant disease marker (such as growth hormone/IGF-1 or tumour symptoms), blood glucose, thyroid function and the gallbladder by ultrasound during prolonged treatment.

Counselling the patient

• Allow the injection to reach room temperature and rotate sites to reduce local discomfort.
• Report right upper abdominal pain, which may indicate gallstones.
• Do not stop the medicine suddenly without specialist advice.

Evidence & guidelines

Somatostatin analogues are a mainstay of medical therapy for acromegaly and functioning neuroendocrine tumours, supported by endocrine and oncology guidelines.