General: As GH-secreting pituitary tumors may sometimes expand, causing serious complications (e.g. visual field defects), it is essential that all patients be carefully monitored. If evidence of tumor expansion appears, alternative procedures may be advisable.
The therapeutic benefits of a reduction in growth hormone (GH) levels and normalization of insulin-like growth factor 1 (IGF-1) concentration in female acromegalic patients could potentially restore fertility. Female patients of childbearing potential should be advised to use adequate contraception if necessary during treatment with octreotide (see USE IN PREGNANCY & LACTATION).
Thyroid function should be monitored in patients receiving prolonged treatment with octreotide.
Cardiovascular related events: Cases of bradycardia have been reported (frequency: common). Dose adjustments of drugs such as beta-blockers, calcium channel blockers, or agents to control fluid and electrolyte balance, may be necessary.
Gallbladder and related events: Cholelithiasis is a very common event during Sandostatin treatment and may be associated with cholecystitis and biliary duct dilatation (see ADVERSE REACTIONS). Additionally, cases of cholangitis have been reported as a complication of cholelithiasis in patients taking Sandostatin in the post-marketing setting. Ultrasonic examination of the gallbladder before, and at about 6- to 12-month intervals during Sandostatin therapy is therefore recommended.
GEP endocrine tumors: During the treatment of GEP endocrine tumors, there may be rare instances of sudden escape from symptomatic control by Sandostatin, with rapid recurrence of severe symptoms.
Glucose metabolism: Because of its inhibitory action on growth hormone, glucagon, and insulin, Sandostatin may affect glucose regulation. Post-prandial glucose tolerance may be impaired and, in some instances, the state of persistent hyperglycemia may be induced as a result of chronic administration. Hypoglycemia has also been reported.
In patients with insulinomas, octreotide, because of its greater relative potency in inhibiting the secretion of GH and glucagon than that of insulin, and because of the shorter duration of its inhibitory action on insulin, may increase the depth and prolong the duration of hypoglycaemia. These patients should be closely monitored during initiation of Sandostatin therapy and at each change of dosage. Marked fluctuations in blood glucose concentration may possibly be reduced by smaller, more frequently administered doses.
Insulin requirements of patients with type I diabetes mellitus therapy may be reduced by administration of Sandostatin. In non-diabetics and type II diabetics with partially intact insulin reserves, Sandostatin administration can result in prandial increases in glycaemia. It is therefore recommended to monitor glucose tolerance and antidiabetic treatment.
Oesophageal varices: Since, following bleeding episodes from esophageal varices, there is an increased risk for the development of insulin-dependent diabetes or for changes in insulin requirement in patients with pre-existing diabetes, an appropriate monitoring of blood glucose levels is mandatory.
Local site reactions: In a 52-week toxicity study in rats, predominantly in males, sarcomas were noted at the s.c. injection site only at the highest dose (about 40 times the maximum human dose). No hyperplastic or neoplastic lesions occurred at the s.c. injection site in a 52-week dog toxicity study. There have been no reports of tumor formation at the injection sites in patients treated with Sandostatin for up to 15 years. All the information available at present indicates that the findings in rats are species specific and have no significance for the use of the drug in humans.
Nutrition: Octreotide may alter absorption of dietary fats in some patients.
Depressed vitamin B12 levels and abnormal Schilling's tests have been observed in some patients receiving octreotide therapy. Monitoring of vitamin B12 levels is recommended during therapy with Sandostatin in patients who have a history of vitamin B12 deprivation.