Genfastat

Genfastat is an analogue of the substance somatostatin. It is used in intensive therapeutic procedures in gastroenterology.

Indications Genfastata

It is used in the following cases:

• acromegaly (if radiotherapy, surgical procedures and the use of dopamine agonists have not had the desired effect);
• neoplasms in which increased production of somatoliberin (STH-RF) is observed;
• elimination of manifestations arising from secreting neoplasms in the gastrointestinal tract (this includes carcinoid neoplasms accompanied by carcinoid syndrome, as well as insulinomas with glucagonomas and gastrinomas);
• prevention of the development of postoperative complications in the pancreas;
• diarrhea refractory to other types of treatment in people with AIDS.

It is also used to stop bleeding and prevent its recurrence in varicose veins of the esophagus in people with liver cirrhosis (combined with endoscopic sclerotherapy).

[ 1 ]

Release form

The therapeutic agent is released in the form of a liquid for subcutaneous or intravenous injections, in glass bottles with a volume of 1 ml. Inside the box there are 5 such bottles.

Pharmacodynamics

Genfastat is an artificial analogue of the element somatostatin, which has a long duration of therapeutic effect. The drug suppresses the release of STH through the anterior pituitary lobe, and in addition, the release of TSH.

At the same time, it suppresses endocrine (glucagon with insulin) and exocrine secretion of the pancreas, processes of secretion of hydrochloric acid with gastrin, secretin with cholecystokinin, vasointestinal peptide with individual other peptides, digestive enzymes and bioactive components, whose secretion is produced through the gastroenteropancreatic system. The drug also suppresses the motor function of the gastrointestinal tract.

[ 2 ]

Pharmacokinetics

After the subcutaneous injection, the medicine is rapidly absorbed into the bloodstream at high speed. The plasma Cmax level of the active ingredient is noted after half an hour. Intraplasmic synthesis with protein is 65%; it binds very weakly to formed blood components. Vd values are 0.27 l/kg.

Total clearance values are 160 ml/min. The half-life with subcutaneous injection is 100 minutes. With intravenous injection, excretion occurs in 2 stages, with half-lives of 10 and 90 minutes, respectively.

[ 3 ], [ 4 ]

Dosing and administration

The medication is used for intravenous and subcutaneous injections.

In case of endocrine neoplasms, the medication is administered subcutaneously, the initial dose is 50 mcg with 1-2 administrations per day. Then, taking into account the obtained result, the effect on the hormone levels produced by the tumor (in case of carcinoid neoplasm - the effect on the secretion of 5-hydroxyindoleacetic acid with urine), as well as tolerance, the dose can be gradually increased to 100-200 mcg with 3-times administration per day. To get a quick response, for example, in case of carcinoid tumors, the initial dosage of the drug is administered in the form of a diluted bolus injection, while monitoring the heart rate level.

If there are no positive changes after 1 week of therapy for a carcinoid tumor, it can be stopped.

In case of acromegaly, the drug is used subcutaneously in an initial dose of 50-100 mcg, which is used at 12-hour intervals. Then the dosage is selected taking into account the results of determining the blood GH indicators, analysis of clinical signs and drug tolerance. Basically, it is required to administer 200-300 mcg of the substance per day. If the GH indicator does not decrease to the required levels after 3 months of therapy, and the clinical picture of the disease does not improve, the treatment is canceled.

To prevent postoperative complications in the pancreas, the first dose of the drug (100 mcg) is administered subcutaneously 60 minutes before laparotomy; then, after the operation, 100 mcg is administered 3 times a day for the next 7 days. Only in exceptional circumstances may higher doses be required. Maintenance doses are selected individually. If there is no result after 1-week treatment with the maximum permissible doses, the course is discontinued.

Preparation of fluid for intravenous procedures.

Immediately before the procedure, the medicinal substance from the vial for multiple use is dissolved in 0.9% NaCl. The medicine must not be dissolved in glucose solution. In this case, the minimum limits of drug dissolution are 1:1, and the maximum are 1:9. To prevent contamination with bacteria, the vial stopper should be punctured a maximum of 10 times. The prepared liquid must be used within the next 8 hours, and the remaining unused substance must be disposed of.

An opened reusable bottle of the medicine (200 mcg/ml) should be kept in the refrigerator (temperature values are within 2-8°C). Its shelf life is 15 days.

Before administration, the liquid is checked for the presence of sediment and particles, as well as for changes in color, transparency and leakage of the bottle.

It is prohibited to use a substance with a changed or cloudy shade, as well as if it contains sediment with particles, and if there are traces of smudges on the bottle.

Use Genfastata during pregnancy

Genfastat can be prescribed to lactating or pregnant women only if there are strict vital indications.

Contraindications

The use of the medication is contraindicated in case of intolerance to octreotide.

[ 5 ], [ 6 ]

Side effects Genfastata

The administration of the drug leads to the appearance of the following side effects:

• Gastrointestinal disorders: vomiting, abdominal pain, anorexia, diarrhea, steatorrhea, nausea and flatulence. Glucose intolerance may occur. Occasionally, there is pain on palpation, sharp pain in the epigastric region, muscle tension in the peritoneum, hyperbilirubinemia and acute hepatitis, and increased activity of liver enzymes. Long-term use sometimes leads to the formation of stones inside the gallbladder;
• local signs: itching, burning sensation, pain, redness and swelling in the injection area.

[ 7 ]

Overdose

Doses of the drug up to 2000 mcg per day, administered in the form of subcutaneous injections over several months, are often tolerated without complications.

With the maximum 1-fold bolus intravenous injection for an adult, amounting to 1000 mcg of the drug, such manifestations as flushing of the skin on the face, decreased heart rate, and in addition, spastic pain in the abdominal area, nausea, diarrhea and a feeling of emptiness in the stomach occur. Such symptoms disappear within 24 hours from the moment of drug administration.

In case of accidental use of too large a dose of octreotide (250 mcg/hour, not 25 mcg/hour) via prolonged infusion, no adverse symptoms have been reported. Acute intoxication also does not result in life-threatening symptoms. Symptomatic measures are taken to eliminate the disturbances.

[ 8 ], [ 9 ]

Interactions with other drugs

Substances similar to somatostatin are capable of reducing the clearance of components whose metabolism is carried out with the help of isoenzymes of the hemoprotein P450 system (this may be associated with the suppression of growth hormone).

Combined use with bromocriptine causes an increase in its bioavailability.

Combination with insulin may potentiate the antidiabetic effect of the drug.

Administration together with cyclosporine reduces the absorption of this element.

The use of Genfastat and cimetidine inhibits the absorption of the latter.

[ 10 ], [ 11 ]

Storage conditions

Genfastat should be kept in a dark place out of reach of children. Do not freeze the medicine. Temperature indicators are within 2-8°C.

Shelf life

Genfastat can be used within 36 months from the date of manufacture of the medicinal substance.

Application for children

There is only limited information regarding the use of the drug in pediatrics, which is why it is not prescribed to children.

Analogues

Analogues of the drug are the medications Octra with Octrestatin and Sandostatin.

[ 12 ]