Octreotide Acetate 83150-76-9

Uses

Approved uses

The Food and Drug Administration (FDA) has approved the usage of a salt form of this peptide, octreotide acetate, as an injectable depot formulation for the treatment of acromegaly, the treatment of diarrhea and flushing episodes associated with carcinoid syndrome, and treatment of diarrhoea in patients with vasoactive intestinal peptide-secreting tumors (VIPomas).

Radiolabelling

Octreotide is used in nuclear medicine imaging by labelling with indium-111 (Octreoscan) to non-invasively image neuroendocrine and other tumours expressing somatostatin-receptors. More recently, it has been radiolabelled with gallium-68 enabling imaging with positron emission tomography (PET) which provides higher resolution and sensitivity. Octreotide can also be labelled with a variety of radionuclides, such as yttrium-90 or lutetium-177, to enable peptide receptor radionuclide therapy (PRRT) for the treatment of unresectable neuroendocrine tumours.

Off-label and experimental uses

Octreotide has also been used off-label for the treatment of severe, refractory diarrhea from other causes. It is used in toxicology for the treatment of prolonged recurrent hypoglycemia after sulfonylurea and possibly meglitinides overdose. Octreotide has also been used with varying degrees of success in infants with nesidioblastosis to help decrease insulin hypersecretion. In patients with suspected esophageal varices, octreotide can be given to help decrease bleeding. Octreotide has been investigated for patients with pain from chronic pancreatitis. It may be useful in the treatment of thymic neoplasms. The drug has been used off-label, injected sub-cutaneously, in the management of hypertrophic pulmonary osteoarthropathy (HPOA) secondary to non-small cell lung carcinoma. Although its mechanism is not known it appears to reduce the pain associated with HPOA. It has been used in the treatment of malignant bowel obstruction. Octreotide may be used in conjunction with midodrine to partially reverse peripheral vasodilation in the hepato-renal syndrome. By increasing systemic vascular resistance, these drugs reduce shunting and improve renal perfusion, prolonging survival until definitive treatment with liver transplant. The drug has also been shown to be effective in the treatment of chylothorax. A small study has shown that octreotide may be effective in the treatment of idiopathic intracranial hypertension (IIH).

Contraindications

Octreotide has not been adequately studied for the treatment of children, pregnant and lactating women. The drug is given to these groups of patients only if a risk-benefit analysis is positive.

Adverse effects

Most frequent adverse effects (more than 10% of patients) are headache, cardiac conduction changes, gastrointestinal reactions (including cramps, nausea/vomiting and diarrhea or constipation), gallstones, high or low blood sugar, and (usually transient) injection site reactions. Slow heart rate, skin reactions like pruritus, hyperbilirubinemia, hypothyreosis, dizziness and dyspnea are also fairly common (more than 1%). Rare side effects include acute anaphylactic reactions, pancreatitis and hepatitis. Data on the frequency of alopecia vary.

Interactions

Octreotide can reduce the intestinal resorption of ciclosporin, possibly making it necessary to increase the dose. Patients with diabetes mellitus might need less insulin or oral antidiabetics when treated with octreotide. The bioavailability of bromocriptine, is increased. Bromocriptine, besides being an antiparkinsonian, is also used for the treatment of acromegaly.