Sandostatin® [Ocreotide]

Pharmacological properties

sandostatin is a synthetic octapeptide, a derivative of the natural hormone somatostatin, which has similar pharmacological effects, but a significantly longer duration of action. the drug suppresses pathologically increased secretion of growth hormone, as well as peptides and serotonin, produced in the gastroenteropancreatic endocrine system.

In animals, octreotide is a more potent inhibitor of the release of growth hormone, glucagon and insulin than somatostatin, with greater selectivity it inhibits growth hormone and glucagon.

In healthy individuals, Sandostatin, like somatostatin, inhibits:

• growth hormone secretion caused by arginine, exercise and insulin hypoglycemia;
• secretion of insulin, glucagon, gastrin and other peptides of the gastroenteropancreatic endocrine system, due to food intake, as well as secretion of insulin and glucagon stimulated by arginine;
• thyrotropin secretion caused by thyroliberin.

Unlike somatostatin, octreotide suppresses growth hormone more than insulin, its administration is not accompanied by ricochet hypersecretion of hormones (that is, growth hormone in patients with acromegaly).

In patients undergoing pancreatic surgery, the use of Sandostatin during and after surgery reduces the incidence of typical postoperative complications (e.g., pancreatic fistulas, abscesses, sepsis, postoperative acute pancreatitis).

In patients with acromegaly, Sandostatin reduces the concentration of growth hormone and insulin-like growth factor-1 (IGF-1) in the blood plasma of most patients. Inhibition of growth hormone by 50% or more is noted in 90% of patients, a decrease in the level of growth hormone in blood plasma of 5 ng / ml is achieved in approximately 50% of patients. In most patients with acromegaly, Sandostatin significantly reduces the severity of symptoms such as headache, hyperhidrosis, fatigue, joint pain, paresthesia, and carpal tunnel syndrome. In patients with pituitary adenoma secreting growth hormone, treatment with Sandostatin may lead to some reduction in tumor size.

In patients with functional endocrine tumors of the gastrointestinal tract and pancreas, Sandostatin provides constant monitoring of symptoms associated with the underlying disease. Below are the effects of octreotide in different types of gastroenteropancreatic tumors. Clinical and symptomatic improvement is noted in patients with symptoms associated with tumors, despite previous treatment, including surgical, embolization of the hepatic arteries and various chemotherapy, for example, the use of streptozocin and fluorouracil.

In carcinoid tumors, the use of Sandostatin can reduce the severity of symptoms such as flushing and diarrhea, which in many cases is accompanied by a decrease in the concentration of serotonin in the blood plasma and a decrease in the excretion of 5-hydroxyindoleacetic acid in the urine.

In tumors characterized by hyperproduction of a vasoactive intestinal peptide (VIP), the use of Sandostatin in most patients leads to a decrease in the severity of secretory diarrhea characteristic of this condition, which, in turn, improves the patients quality of life. At the same time, the number of concomitant disturbances in the electrolyte balance, for example, hypokalemia, is reduced, which allows you to cancel the enteral and parenteral administration of fluid and electrolytes. In some patients, a slowdown or cessation of tumor progression and even a decrease in its size, especially liver metastases, are noted. Clinical improvement is usually accompanied by a decrease (up to normal values) in the concentration of VIP in blood plasma.

With glucagonomas, the use of Sandostatin in most cases leads to a noticeable decrease in the severity of a necrotizing migratory rash, characteristic of this condition. Sandostatin does not have any significant effect on the severity of mild diabetes, which is often noted with glucagonomas, and usually does not reduce the need for insulin or oral hypoglycemic drugs. In patients with diarrhea, Sandostatin causes a decrease in its severity, which is accompanied by an increase in body weight. With the use of Sandostatin, a rapid decrease in the concentration of glucagon in the blood plasma is often noted, however, with prolonged treatment, this effect does not persist. At the same time, symptomatic improvement remains stable for a long time.

For gastrinomas / Zollinger – Ellison syndrome, Sandostatin used as monotherapy or in combination with proton pump inhibitors or H antagonists₂receptors, can reduce the production of hydrochloric acid in the stomach and cause clinical improvement, including in relation to diarrhea. It is also possible to reduce the severity and other symptoms, probably due to the synthesis of peptides by the tumor, including hot flashes. In some cases, a decrease in the concentration of gastrin in the blood plasma is noted.

In patients with insulinomas, Sandostatin reduces the level of immunoreactive insulin in the blood (this effect, however, can be short-term - about 2 hours). In patients with an operable tumor, Sandostatin can restore and maintain normoglycemia in the preoperative period. In patients with inoperable benign and malignant tumors, glycemic control can improve without a simultaneous prolonged decrease in insulin levels in the blood.

In patients with a tumor that hyperproduces the releasing factor (RF) of growth hormone (somatoliberinomas), Sandostatin reduces the severity of acromegaly symptoms. This, apparently, is associated with suppression of the secretion of the RF growth hormone and growth hormone itself. In the future, pituitary hypertrophy may decrease.

With refractory diarrhea in AIDS patients, the use of Sandostatin leads to a complete or partial normalization of stool in approximately ¹/₃ patients with diarrhea not controlled by adequate antimicrobial and / or antidiarrheal therapy.

In patients undergoing pancreatic surgery, the use of Sandostatin during and after surgery reduces the incidence of typical postoperative complications (e.g., pancreatic fistulas, abscesses, sepsis, postoperative acute pancreatitis).

When bleeding from varicose veins of the esophagus and stomach in patients with cirrhosis of the liver, the use of Sandostatin in combination with specific treatment (for example, sclerotherapy) led to a more effective stop of bleeding and early rebleeding, a decrease in the volume of transfusions and an increase in 5-day survival. Although the mechanism of action of Sandostatin is not precisely established, it is believed that the drug reduces organ blood flow by suppressing vasoactive hormones such as VIP and glucagon.

Pharmacokinetics Absorption. After SC administration, Sandostatin is rapidly and completely absorbed. C_max drug in blood plasma is reached after 30 minutes.

Distribution. Binding to plasma proteins is 65%. The binding of Sandostatin to blood cells is extremely negligible. The volume of distribution is 0.27 l / kg body weight.

The total clearance is 160 ml / min. T_½ drug after sc injection - 100 min. After iv administration, the drug is excreted in two phases with T_½ 10 and 90 min, respectively. Most of the administered dose of the peptide is excreted in the feces, about 32% - unchanged in the urine.

Impaired renal function does not affect the total exposure (AUC) of octreotide administered sc.

Impaired liver function. The ability to eliminate can be reduced by 30% in patients with cirrhosis.

Indications

Acromegaly: to control the main manifestations of the disease and reduce the level of growth hormone and insulin-like growth factor (IGF) -1 in blood plasma in cases where there is no sufficient effect from surgical treatment and radiation therapy. sandostatin is also indicated for the treatment of patients with acromegaly who have refused surgery or with contraindications for it, as well as for short-term treatment in the intervals between courses of radiation therapy until its effect is fully manifested.

Reducing the severity of symptoms of endocrine tumors of the gastrointestinal tract and pancreas:

• carcinoid tumors with the presence of carcinoid syndrome;
• VIPoma (tumors characterized by hyperproduction of VIP);
• glucagonomas;
• gastrinomas / Zollinger-Ellison syndrome - usually in combination with N antagonists₂receptors or proton pump inhibitors;
• insulinomas (to control hypoglycemia in the preoperative period, as well as for maintenance therapy);
• somatoliberinomas (tumors characterized by hyperproduction of RF growth hormone).

Sandostatin is not an antitumor drug, and its use cannot lead to the cure of this category of patients.

Prevention of complications after pancreatic surgery

Stopping bleeding and preventing recurrence of bleeding from varicose veins of the esophagus in patients with cirrhosis (in combination with specific therapeutic measures, for example, with endoscopic sclerotherapy).

Application

With acromegaly, the drug is initially administered at 0.05-0.1 mg s / c 3 times a day. in the future, the dose is set on the basis of monthly determinations of the concentration of growth hormone and ifr-1 in the blood, analysis of clinical symptoms and tolerance to the drug (target concentrations of hormones in the blood are: growth hormone 2.5 ng / ml, ifr-1 - within normal limits). for most patients, the optimal daily dose is 0.2-0.3 mg. do not exceed the maximum daily dose of 1.5 mg. in patients who receive a stable dose of sandostatin, growth hormone concentration should be determined every 12 months. in patients with adequate control of clinical and biochemical parameters, a 6-month monitoring may be required.

If after 3 months of treatment with Sandostatin, a sufficient decrease in the level of growth hormone and improvement of the clinical picture of the disease is not noted, therapy should be discontinued.

With endocrine tumors of the gastrointestinal tract and pancreas, the drug is administered sc in an initial dose of 0.05 mg 1-2 times a day. In the future, depending on the achieved clinical effect, the dose of the drug can be gradually increased to 0.2 mg 3 times a day. In exceptional cases, the use of the drug in higher doses may be required. Maintenance doses of the drug should be set individually. A subcutaneous route of administration is recommended, however, in cases where a rapid clinical effect, such as a carcinoid crisis, is required, the initial recommended dose of Sandostatin can be administered using a bolus dose after dilution with heart rate monitoring.

If, within 1 week of treatment with Sandostatin, carcinoid tumors do not improve, further therapy is not recommended.

To prevent complications after pancreatic surgery, the drug is administered s.c. 0.1 mg 3 times a day for 7 consecutive days starting from the day of surgery (at least 1 hour before laparotomy).

In case of bleeding from varicose veins of the esophagus, administer the drug at a dose of 25 μg / h by continuous infusion for 5 days. Sandostatin can be diluted with 0.9% sodium chloride chloride.

Use in patients with impaired renal function.Impaired renal function does not affect the total exposure (AUC) of octreotide, which was administered by sc injection. Therefore, dose adjustment of Sandostatin is not required.

Use in patients with impaired liver function. In patients with cirrhosis of the liver T_½ may increase, which requires correction of the maintenance dose.

Use in the elderly. There is no evidence of reduced tolerance or the need for dose adjustment in elderly patients who received Sandostatin treatment.

Contraindications

Hypersensitivity to octreotide or other components of the drug.

Side effects

The most common adverse reactions during treatment with octreotide include disorders of the gastrointestinal tract, nervous system, liver and gall bladder, metabolism and trophism.

The adverse reactions most commonly reported during clinical trials of octreotide were diarrhea, abdominal pain, nausea, flatulence, headache, cholelithiasis, hyperglycemia, and constipation. Other commonly reported adverse reactions are dizziness, local pain, biliary calculi, thyroid dysfunction (e.g., decreased thyroid-stimulating hormone, decreased total T4 and free T4), loose stools, impaired glucose tolerance, vomiting, asthenia, and hypoglycemia .

In isolated cases, adverse reactions from the gastrointestinal tract can resemble acute intestinal obstruction - progressive bloating, severe pain in the epigastric region, abdominal tenderness and muscle tension.

Sensation of acute pain, tingling, or burning at the injection site with redness and swelling rarely lasts 15 minutes. To reduce the feeling of local discomfort, the injection solution should be at room temperature.

Although the excretion of fat with feces may increase, there is no indication that prolonged treatment with Sandostatin may lead to nutritional deficiency due to malabsorption (malabsorption).

Side effects from the gastrointestinal tract can be reduced by increasing the interval between meals and the introduction of Sandostatin. It is recommended to introduce the drug between meals or at bedtime.

In rare cases, the development of acute pancreatitis has been reported. This phenomenon is usually observed in the first hours or days of treatment with Sandostatin and disappears after discontinuation of the drug. In addition, in patients receiving Sandostatin in the form of sc injections for a long time, the development of pancreatitis due to cholelithiasis is possible.

There were isolated cases of biliary colic after a sharp discontinuation of the drug in patients with acromegaly, in whom calculi formed in the gall bladder.

In patients with acromegaly and carcinoid syndrome, ECG changes such as lengthening of the Q – T interval, axis shift, early repolarization, low voltage of the teeth, R / S transition, early increase in the R wave, and non-specific ST – T wave changes were detected. The relationship between these phenomena and the use of octreotide acetate has not been established, since most of these patients had a history of diseases of the cardiovascular system (see SPECIAL INSTRUCTIONS).

Adverse reactions listed below in table. 1, obtained during clinical trials of octreotide.

Adverse reactions to the drug are distributed by frequency: very often (≥1 / 10); often (≥1 / 100, 1/10); infrequently (≥1 / 1000, 1/100); rarely (≥1 / 10,000, 1/1000); very rarely (1/10 000), including single messages. In each frequency group, adverse reactions are arranged in decreasing order of severity.

Table 1 Adverse Reactions to the Drug Reported in Clinical Studies

From the gastrointestinal tract
Often	Diarrhea, abdominal pain, nausea, constipation, flatulence
Often	Dyspepsia, vomiting, bloating, steatorrhea, frequent loose stools, feces discoloration
From the nervous system
Often	Headache
Often	Dizziness
Endocrine system
Often	Hypothyroidism, thyroid dysfunction (e.g., decreased thyroid-stimulating hormone, decreased total T4 and free T4)
From the hepatobiliary system
Often	Cholelithiasis
Often	Cholecystitis, bile calculi, hyperbilirubinemia
On the part of metabolism and nutrition
Often	Hyperglycemia
Often	Hypoglycemia, impaired glucose tolerance, anorexia
Infrequently	Dehydration
General disorders and disorders at the injection site
Often	Pain at the injection site
Laboratory research
Often	Increased transaminase levels
On the part of the skin and subcutaneous tissue
Often	Itching, rash, alopecia
From the respiratory system
Often	Dyspnoea
From the cardiovascular system
Often	Bradycardia
Infrequently	Tachycardia

Post-marketing research. On the adverse reactions indicated in the table. 2, reported voluntarily in spontaneous messages, while it is not always possible to reliably establish the frequency or cause-effect relationship with the drug.

Table 2 Adverse reactions to the drug described in spontaneous reports

From the immune system	Anaphylaxis, Allergy / Hypersensitivity Reactions
On the part of the skin and subcutaneous tissue	Hives
From the hepatobiliary system	Acute pancreatitis, acute hepatitis without cholestasis, cholestatic hepatitis, cholestasis, jaundice, cholestatic jaundice
From the cardiovascular system	Arrhythmia
Changing laboratory indicators	Increased levels of alkaline phosphatase, gamma glutamyl transferase

special instructions

S / c introduction. Patients who administer the drug themselves by SC injection should receive precise instructions from a doctor or nurse.

In order to reduce discomfort at the injection site, it is recommended to bring the solution to room temperature before injection. Repeated injections at the same site over a short period of time should be avoided.

Ampoules must be opened only before administration, the remaining drug should be disposed of.

In / in infusion. The diluted solution remains physically and chemically stable for at least 24 hours at a temperature of no higher than 25 ° C.

General Provisions Since sometimes a pituitary tumor secreting growth hormone can grow, causing serious complications (for example, narrowing of the visual field), careful monitoring of the patients condition is essential. In case of signs of tumor enlargement, the need for alternative treatments should be considered.

The therapeutic benefits of lowering growth hormone levels and normalizing the concentration of IGF-1 in women with acromegaly can potentially restore fertility. During treatment with octreotide, women of reproductive age should be advised to use adequate methods of contraception (see. Use during pregnancy and lactation).

In patients receiving long-term therapy with octreotide, it is necessary to control the function of the thyroid gland (TSH and thyroid hormones). During octreotide therapy should be monitored