What is the injection for GI bleeding?: A Comprehensive Guide to Pharmacologic and Endoscopic Treatments

October 13, 2025 •

4 min read

Endoscopic therapy has replaced surgery as the primary intervention for many gastrointestinal (GI) bleeding disorders. A critical aspect of this management is understanding what is the injection for GI bleeding?, a question that involves different pharmacologic strategies for controlling hemorrhage depending on its cause and location.

Quick Summary

Different injections are used for GI bleeding, including endoscopic therapies like epinephrine and sclerosants, and systemic medications such as octreotide and vasopressin. The choice depends on the bleeding's origin (e.g., variceal or non-variceal) and severity.

Key Points

Epinephrine Injection: Provides temporary hemostasis via vasoconstriction and tamponade and is typically combined with other endoscopic methods like clips or cautery for durable results.
Endoscopic Sclerosants: Agents like polidocanol and ethanol are injected directly into or around the bleeding site to induce vessel thrombosis and sclerosis, offering a more definitive treatment.
Octreotide: A systemic medication, this is a first-line treatment for controlling bleeding from esophageal or gastric varices by causing splanchnic vasoconstriction and reducing portal pressure.
Vasopressin: An older systemic agent that causes widespread vasoconstriction to treat variceal bleeding, but it is used less frequently than octreotide due to potential cardiac side effects.
Hemostatic Powders: Delivered endoscopically, powders like Hemospray form a mechanical barrier to control diffuse or difficult-to-treat bleeding, serving as a valuable rescue therapy.
Angiographic Embolization: In refractory cases, interventional radiologists inject coils, particles, or glue into the feeding artery via a catheter to occlude the vessel and stop the bleed.
Variceal vs. Non-variceal Bleeding: The choice of injection is fundamentally different for these two categories. Octreotide and vasopressin are for variceal bleeding, while endoscopic epinephrine, sclerosants, and clips are often used for non-variceal sources.

An Introduction to Injections for GI Bleeding

In medical practice, the term "injection for GI bleeding" can refer to several distinct procedures and medications. The approach depends heavily on the cause of the hemorrhage, whether it originates from varices (enlarged veins) or non-variceal sources like ulcers or vascular malformations. The main strategies include endoscopic injections, systemic pharmacologic agents, and, in refractory cases, angiographic embolization.

Endoscopic Injection Therapies

Endoscopic injection is a cornerstone of GI bleeding management, performed during an endoscopy to deliver medication directly to the bleeding site. These injections provide localized hemostasis through various mechanisms, such as vasoconstriction, tamponade, and sclerosis.

Epinephrine: Diluted epinephrine (typically 1:10,000) is one of the most common endoscopic injectable agents. It acts by inducing powerful local vasoconstriction and creating a compression (tamponade) effect due to the volume of the fluid injected. While effective for initial hemostasis, it is rarely used alone because its effect is temporary. Combination therapy, where epinephrine injection is followed by a more definitive treatment like thermal coagulation or mechanical clipping, is considered superior for preventing rebleeding.
Sclerosants: These agents, including absolute ethanol and polidocanol, are injected to cause a local inflammatory reaction that results in thrombosis (blood clot formation) and fibrosis of the vessel. Sclerosants provide more definitive hemostasis than epinephrine alone, but they carry a higher risk of tissue damage and potential complications like perforation. Polidocanol is effective for both non-variceal and variceal bleeding.
Cyanoacrylate Glue: For bleeding gastric varices, injecting cyanoacrylate glue (Histoacryl) directly into the vessel can achieve high initial hemostasis rates. The glue rapidly polymerizes on contact with blood, creating a cast inside the varix that seals the bleed. It is a highly specialized procedure, as it carries a risk of systemic embolization.
Hemospray (TC-325): This is an inorganic hemostatic powder delivered via a catheter through the endoscope to the bleeding site. It forms an adhesive, cohesive mechanical barrier that promotes clot formation. It is particularly useful for diffuse or difficult-to-reach bleeding, or as a rescue therapy, but its effect is temporary, similar to epinephrine.

Systemic Pharmacologic Agents

For certain types of bleeding, particularly variceal hemorrhage associated with portal hypertension, systemic injections are used to reduce blood flow in the GI system.

Octreotide (Sandostatin): A synthetic analogue of the hormone somatostatin, octreotide is a key systemic medication for controlling variceal bleeding. It works by causing vasoconstriction in the splanchnic blood vessels that supply the gut, thereby reducing portal venous pressure. It also reduces stomach acid and pepsin secretion. While highly effective for variceal bleeds, its use in non-variceal bleeding is less established and often limited to refractory cases.
Vasopressin: This hormone causes widespread vasoconstriction, including in the splanchnic circulation, which helps control variceal bleeding. However, its use is limited by significant systemic side effects, such as coronary artery constriction. It is often administered with nitrates to mitigate these risks. In modern practice, octreotide is often preferred due to its comparable efficacy and better side-effect profile.

Interventional Radiology (IR) Embolization

When endoscopic and pharmacologic methods fail, or for cases of massive hemorrhage, a procedure known as transarterial embolization (TAE) may be performed. Under imaging guidance, a radiologist inserts a catheter into an artery and guides it to the bleeding vessel. Injectable agents like coils, particles, or liquid glue are then used to block the vessel, effectively stopping the bleeding. This is a highly effective rescue therapy for refractory bleeding.

Comparing Different Injection Methods


Injection Agent/Type	Mechanism of Action	Common Use Cases	Administration Route	Advantage	Disadvantage
Endoscopic Epinephrine	Vasoconstriction, Tamponade	Peptic ulcers, Post-polypectomy	Endoscopic, direct	Fast, easily accessible	Temporary effect, high rebleeding risk as monotherapy
Endoscopic Sclerosants	Thrombosis, Fibrosis	Bleeding varices, Ulcers	Endoscopic, direct	More definitive hemostasis	Risk of tissue necrosis and perforation
Endoscopic Cyanoacrylate	Polymerization, Cast formation	Gastric varices	Endoscopic, direct	Highly effective for varices	Risk of systemic embolization, specialized technique
Systemic Octreotide	Splanchnic Vasoconstriction	Variceal bleeding, Angiodysplasia	Intravenous (IV), subcutaneous (SC)	Reduces portal pressure, fewer side effects than vasopressin	Less effective for non-variceal bleeding
Systemic Vasopressin	Widespread Vasoconstriction	Variceal bleeding	IV, intra-arterial	Rapidly reduces portal pressure	Significant systemic side effects (cardiac ischemia)
Angiographic Embolization	Vessel Occlusion	Refractory hemorrhage, inaccessible bleeds	Intra-arterial catheter	Definitive control of major bleeds	Invasive, specialized procedure, risk of bowel ischemia

Conclusion

In summary, there is no single answer to "what is the injection for GI bleeding?" because multiple agents and techniques are used, depending on the specifics of the bleeding. From localized endoscopic injections with epinephrine to systemic drugs like octreotide for variceal bleeding and interventional embolization for complex cases, the treatment strategy is tailored to the individual patient. Successful management requires accurate diagnosis and stabilization, often followed by a combination of therapies to ensure durable hemostasis and prevent rebleeding.

For more information on digestive health, you can consult resources like the American College of Gastroenterology (ACG).

Frequently Asked Questions

The most common injection is a diluted epinephrine solution. It is typically delivered directly into or around the bleeding site to cause vasoconstriction and tamponade, temporarily stopping the bleeding for better visualization and combination therapy.

Systemic side effects from endoscopic epinephrine injection are rare, especially with standard doses, because the drug is primarily metabolized by the liver before it can reach significant systemic circulation. However, higher doses or injections near the gastroesophageal junction may increase this risk.

Octreotide is primarily used for GI bleeding caused by esophageal or gastric varices associated with portal hypertension. It is a systemic injection that works by reducing blood flow to the GI tract and lowering portal venous pressure.

Both vasopressin and octreotide are used to control variceal bleeding by reducing splanchnic blood flow. However, octreotide has largely replaced vasopressin in clinical practice because it has a better safety profile with fewer significant side effects, particularly regarding cardiac complications.

For active or high-risk bleeding, injections are often combined with other techniques, such as thermal coagulation or mechanical clips, to ensure permanent hemostasis. Epinephrine as a monotherapy, for instance, has a high rebleeding rate.

Hemostatic powders, such as Hemospray, are applied topically through an endoscope to form a mechanical barrier over a bleeding site. They are particularly useful for diffuse or hard-to-reach bleeding, or as a rescue therapy when conventional methods have failed.

If initial endoscopic treatments fail, repeat endoscopic therapy may be attempted, often using different modalities. If bleeding persists, a patient may need transarterial embolization (TAE) performed by interventional radiology or, in some cases, surgery.