Octreotide
Synonym :
Somatostatin
Mechanism :
Octreotide exerts pharmacologic actions similar to the natural hormone, somatostatin. It is an even more potent inhibitor of growth hormone, glucagon, and insulin than somatostatin. Like somatostatin, it also suppresses LH response to GnRH, decreases splanchnic blood flow, and inhibits release of serotonin, gastrin, vasoactive intestinal peptide, secretin, motilin, and pancreatic polypeptide.
Indication :
- Hyperinsulinemia- if glucagon, diazoxide, and chlorothiazide fail
- Oesophageal/gastric variceal bleed
- Severe diarrhea in carcinoid syndromes and intestinal tumors
- Chylothorax
- Sulphonyl urea overdose
Contraindications :
Contraindicated in known hypersensitivity to octreotide or any excipient. As it inhibits gall bladder motility, bile acid secretion and bile flow, worsening of liver disease in patients whose disease stems from biliary obstruction might be anticipated. There is a clear association between octreotide therapy and the formation of gallstones. Monitor thyroid function on long-term therapy.
Dosing :
Varices/GI Bleeding:
1 mcg/kg bolus, then IV Infusion 1 mcg/kg/hour. Then taper by 50% when there is no active bleeding over 24 hours.
Hyperinsulinemia, Intractable diarrhea:
2-10 mcg/kg/day SC/IV in 2 divided doses.
Chylothorax:
0.3-4 mcg/kg/hour IV.
Sulphonyl urea overdose:
1 mcg/kg every 12 hours SC/IV, monitor blood glucose levels.
Adverse Effect :
Common side effects include, decreased gall bladder contractility, gallstones, cholestatic hepatitis, cholecystitis, hypothyroidism, bradycardia, dysglycemia.
Other side effects are: Pain, tingling or burning sensation at the injection site, redness and swelling, anorexia, nausea, abdominal pain, bloating, flatulence, diarrhoea and steatorrhea.
Interaction :
Cyclosporine: May decrease blood levels of cyclosporine and result in transplant rejection
Insulin, oral hypoglycemic agents, beta blockers, calcium channel blockers, or agents to control fluid and electrolyte balance: may require dose adjustments of these therapeutic agents.
Bromocriptine: Increases the availability of bromocriptine.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unknown dialysability. Dose as in normal renal function |
| HD | Dialysed. Dose as in normal renal function |
| HDF/High flux | Dialysed. Dose as in normal renal function |
| CAV/VVHD | Unknown dialysability. Dose as in normal renal function |
Hepatic Dose :
Use caution when administering to children. The dosage of octreotide should be halved in patients suffering from hepatic impairment, and then depending on clinical response, titrated.
For depot suspensions administered IM, the dose is halved in cirrhosis.
Specific guidelines for SC or IV injection are not available, however dosing should be started at less than the lower end of dosing range and then titrated based on response.