Human Secretin Injection for Diagnosis of Gastrinoma

Overview:

Human secretin injection is utilized to diagnose gastrinoma, a pancreatic or colon tumor. One useful test is the secretin stimulation test to distinguish Zollinger-Ellison syndrome (ZES) cases from other hypergastrinemia conditions. Inducing gastrin secretin in gastrinoma cells facilitates the diagnosis. The gastrin levels are measured after injecting human secretin. A rise in serum gastrin concentration upon injection indicates gastrinoma. The test is an important diagnostic tool for ZES and gastrinoma. In 2004, the United States Food and Drug Administration (USFDA) approved Human secretin injection to diagnose gastrinoma.

Drug Group:

Human secretin injections are given for various gastrointestinal and pancreatic diagnostic procedures. They stimulate pancreatic secretions, aid in identifying certain malignancies, identify particular anatomical structures during endoscopy and diagnose pancreatic problems. The medication is used for these particular diagnostic reasons under the guidance of a physician.

Dosages:

Available in two strengths:

10 mL(milliliters) vials containing 16 mcg(micrograms) of Human secretin as a lyophilized, sterile powder.

In 10-milliliter vials containing 40 micrograms of Human secretin, as a lyophilized sterile powder.

For Patients:

What Is Gastrinoma?

Gastrin is a hormone released by gastrinoma, a rare kind of neuroendocrine tumor, and it increases the stomach's acid production. Stomach and small intestine ulcers are common symptoms of Zollinger-Ellison syndrome, frequently linked to these malignancies. Gastrinomas associated with hereditary disorders, such as multiple endocrine neoplasia type 1 (MEN-1), can occur irregularly. Most often, they occur in the duodenum but can also be seen in the pancreas or stomach. While total resection results in a high survival rate, surgical removal offers a decent chance of recovery. There is a noticeable recurrence rate, which highlights the value of ongoing monitoring.

What Is the Diagnosis and Management of Gastrinoma?

Low stomach pH and high gastrin levels (>1000 pg/mL) are diagnostic criteria for gastrinoma. Endoscopic ultrasonography is used to locate tumors. Surgery is used to treat localized tumors larger than 0.7 inches, while PPIs are used to manage symptoms. In the case of non-metastatic pancreatic gastrinomas, surgical excision is curative. The standard treatment for MEN1-associated cases is medication. For metastatic disease, somatostatin analogs and chemotherapy are available, and targeted treatments appear to be promising. Serum gastrin levels should be regularly monitored following resection. An interdisciplinary approach is essential to the efficient treatment of gastrinomas.

How Does Human Secretin Injection Work?

Human secretin injection increases pancreatic secretions, which helps with the diagnosis and identification of pancreatic problems. Endoscopy aids in finding the accessory papilla and Vater ampulla—additionally, secretin aids in the diagnosis of diseases such as gastrinoma. The hormone can improve renal blood flow, lower systemic resistance, and raise cardiac output. Secretin can activate brown adipose tissue and promote the release of pancreatic polypeptides, which can affect the regulation of appetite.

What Must the Patient Inform the Doctor Before Taking Human Secretin Injection?

Before receiving a Human secretin Injection for the diagnosis of gastrinoma, patients are required to notify their physician about the following:

• Patients should not use H2 blockers, proton pump inhibitors, or anticholinergic medications to prevent inaccurate diagnostic findings.

• Make sure the physician is made aware of the FDA-approved uses of Human secretin, which include promoting pancreatic secretions, assisting in the diagnosis of gastrinoma, and making identification easier during endoscopy.

• To avoid any negative effects, tell the doctor about any current allergies, medical conditions, and continuing therapies.

• To guarantee secure and efficient diagnostic processes, it is imperative to maintain open communication with healthcare providers.

What Are the Side Effects of Using Human Secretin Injection for Diagnosis of Gastrinoma?

• Nausea.

• A feeling of warmth.

• Redness of the face, neck, arms, and occasionally upper chest.

• Stomach upset.

• Vomiting.

• Other side effects like diarrhea, cold signs and symptoms, and sore throat may also occur.

For Doctors:

Description:

In reaction to acidification, cells in the duodenum generate the gastrointestinal peptide hormone known as Human secretin. The pure synthetic peptide Human secretin, like acetate, has the same amino acid sequence as the natural hormone. The chemical definition of synthetic Human secretin is as follows:

• Weight in Molecules: 3039.44

• Empirical Formula: C130H220N44O39

• Formula for Structure: Leu-Ser-Asp-Gly-Thr-Phe-Thr-Ser-Glu-Leu-Arg-Glu-GlyAla-Arg-Leu-Gln-Arg-Leu-Leu-Gln-Gly-Leu-Val-NH2

There are two strengths available for Human secretin:

In a 10 ml vial containing 20 mg of mannitol, 9 mg of sodium chloride, 1.5 mg of L-cysteine hydrochloride, and 16 mcg of purified synthetic Human secretin.

Dosage and Administration:

• To assist in the identification of exocrine pancreas malfunction, stimulation of pancreatic secretions is used.

• 0.2 mcg/kg (micrograms per kilogram) body weight administered intravenously over one minute.

• To help diagnose gastrinoma, gastrin secretion can be stimulated. An intravenous injection lasting one minute should contain 0.4 mcg/kg of body weight.

• Facilitation of Vater's ampulla and accessory papilla identification during endoscopic retrograde cholangiopancreatography (ERCP).

• Intravenous injection of 0.2 mcg/kg body weight administered over a minute.

Indications:

Human secretin injections are used for the following:

• Stimulation of pancreatic secretions, such as bicarbonate, to help with exocrine pancreas dysfunction diagnosis.

• Inducing gastrin secretion stimulation to facilitate gastrinoma diagnosis.

• Making it easier to identify the accessory papilla and Vater ampulla during endoscopic retrograde cholangiopancreatography (ERCP).

Contraindications:

Human secretin should only be administered to patients with acute pancreatitis once the acute episode concludes.

Warning and Precautions:

• Patients should get a test dose of 0.1 mL of the appropriately reconstituted vial intravenously due to the possibility of an allergic reaction to Human secretin. The prescribed dose may be administered gradually over a minute if no indications of an allergic reaction are seen after that time. Patients who have a history of asthma or atopic allergies should pay particular attention to taking a test dosage. There should be quick access to appropriate treatments for acute hypersensitivity reactions.

• Individuals with inflammatory bowel illness or those who have had vagotomies may not respond well to secretin stimulation. Results of secretin stimulation testing in these patients should be read cautiously, as this reaction does not suggest pancreatic illness.

• Patients who are alcoholic or have other liver diseases may occasionally exhibit a larger-than-normal volume response to secretin stimulation, which may conceal concomitant pancreatic disease. Therefore, care should be used while interpreting the results of secretin stimulation tests in these patients.

What Are the Adverse Reactions of Human Secretin Injection for Diagnosis of Gastrinoma?

• Rash.

• Hives.

• Difficulty breathing.

• Swelling.

• Chest tightness.

• Hoarseness.

What Are the Pharmacological Aspects of Human Secretin Injection for Diagnosis of Gastrinoma?

Mechanism of Action:

When gastric acid, fatty acids, and amino acids are exposed to the proximal intestinal lumen, the hormone secretin is often released from the duodenum. In the intestinal mucosa, enterochromaffin cells release secretin. It has been determined that the pancreas, stomach, liver, colon, and other tissues all contain secretin receptors. Bicarbonate-rich pancreatic fluid is secreted when secretin interacts with secretin receptors on pancreatic duct cells, opening cystic fibrosis transmembrane conductance regulator (CFTR) channels. Since atropine inhibits secretin-stimulated pancreatic secretion and stimulation of the efferent vagus nerve increases bicarbonate production, secretin may also act through vagal-vagal neuronal pathways.

Pharmacokinetics:

Twelve healthy individuals had their PK profiles for synthetic Human secretin assessed. Synthetic Human secretin concentration quickly drops to baseline secretin levels within 90 to 120 minutes following intravenous bolus injection of 0.4 mcg/kg. Synthetic Human secretin has a half-life of elimination of 45 minutes. Synthetic Human secretin has a volume of distribution of 2.7 L and a clearance of 580.9 ± 51.3 mL/min.

Drug Interactions:

• Atropine.

• Benztropine.

• Cimetidine.

• Cyclizine.

• Darifenacin.

• Dexlansoprazole.

• Dicyclomine.

• Dimenhydrinate.

• Esomeprazole.

• Famotidine.

• Fesoterodine.

• Flavoxate.

• Glycopyrrolate.

• Hyoscyamine.

• Hyoscyamine spray.

• Ibuprofen/famotidine.

• Lansoprazole.

• Meclizine.

• Methscopolamine.

• Nizatidine.

• Omeprazole.

• Oxybutynin.

• Oxybutynin topical.

• Oxybutynin transdermal.

• Pantoprazole.

• Propantheline.

• Rabeprazole.

• Scopolamine.

• Solifenacin.

• Tolterodine.

• Trihexyphenidyl.

• Trospium chloride.

Use in Specific Populations:

• Pregnancy: Studies on animal reproduction using synthetic Human secretin have not been carried out. Furthermore, it is unknown if synthetic Human secretin can impair a woman's ability to reproduce or harm a fetus when given to a pregnant woman. Pregnant women should only be administered synthetic Human secretin if it is necessary.

• Lactation: The excretion of synthetic Human secretin in human milk is unknown. When giving synthetic Human secretin to a nursing mother, care should be taken because numerous medications are excreted in human milk.

• Pediatrics: There is no proof of safety or efficacy in pediatric patients.

• Geriatrics: 18 percent and 6 percent of the 533 patients who underwent Human secretin clinical trials were 65 years of age or older, respectively. The dosage applied to each patient was the same as it was to the entire group. There were no general differences in safety, pharmacologic response, or diagnostic efficacy compared to younger participants. Although differences in reactions between older and younger patients have not been noted in other recorded clinical experiences, it is not impossible to rule out the possibility that certain older patients are more sensitive to Human secretin.

Clinical Studies:

• The exocrine pancreas is stimulated to secrete pancreatic juice when Human secretin is injected intravenously. This can help identify exocrine pancreas malfunction. It has been demonstrated that patients with a recognized pancreatic illness exhibit a range of normal values for the pancreatic secretory response to intravenous secretin. Variations in operating methods among investigators are one cause of variation. A total of 18 patients with a history of chronic pancreatitis were given sHS (human secretin), sPS (porcine secretin), and bPS (biologically derived porcine secretin) in two crossover investigations (CRC (colorectal cancer) 98-2 and CRC99-9). Healthy subjects were given sHS in a different trial.

• Intravenous administration of Human secretin promotes the release of gastrin in patients suffering from gastrinoma; in contrast, normal subjects and patients suffering from duodenal ulcer illness do not exhibit any significant changes in serum gastrin concentrations. The secretin stimulation test has been shown to have good sensitivity and specificity in the diagnosis of gastrinoma. Deveney et al. employed discriminant analysis to determine that the ideal criterion for differentiating between positive and negative test results was an increase from the baseline of greater than 110 pg/mL (picograms per milliliter). The use of synthetic Human secretin as a provocative test in the assessment of patients for whom gastrinoma is a diagnostic consideration is based on this gastrin reaction.

• Regarding gastrin levels, there was an agreement between synthetic Human secretin, synthetic pig secretin, and biologically derived porcine secretin in three-way crossover research including six patients with tissue-diagnosed gastrinoma.

• Following stimulation with 0.4 mcg/kg secretin, serum gastrin levels were reported to be >110 pg/mL for all secretin products tested. Twelve healthy participants who underwent Human secretin testing showed negative results for gastrinoma.