ENDOCRYL (N-BUTYL CYANOACRYLATE) 0.5ML INJECTION 5`S

ENDOCRYL contains N-butyl cyanoacrylate (NBCA), a liquid tissue adhesive that polymerises rapidly on contact with ionic fluids such as blood, forming a solid cast that mechanically occludes blood vessels or seals tissue defects. The polymerisation is exothermic and occurs within seconds.

ENDOCRYL is used exclusively in endoscopic and interventional radiology settings for:

·       Endoscopic injection sclerotherapy of gastric varices (dilated veins in the stomach caused by portal hypertension, often due to liver cirrhosis)

·       Treatment of bleeding gastric varices that have failed conventional band ligation or other therapies;

·       Endovascular embolisation of vascular malformations and haemorrhagic lesions.

For gastric varices, NBCA is mixed with lipiodol (an oily contrast medium) in a ratio determined by the operator (typically 1:1 to 1:2) to control polymerisation speed and allow safe injection through the endoscope. This combination is the standard of care for gastric variceal bleeding in many guidelines.

ENDOCRYL is administered exclusively by trained gastroenterologists, endoscopists, or interventional radiologists using specialised injection needles. It must never be self-administered or given outside a procedure suite.

Endoscopic Injection (Gastric Varices)

•       Mix NBCA with lipiodol immediately before injection (typically 0.5 mL NBCA with 0.5–1.0 mL lipiodol — exact ratio adjusted by operator for desired setting time).

•       Inject 0.5–1.0 mL of the mixture directly into the variceal lumen using an endoscopic injection needle.

•       Flush immediately with 1 mL of normal saline or lipiodol to push the adhesive into the varix and prevent the needle from bonding.

•       Withdraw the needle rapidly to avoid injection channel adhesion.

•       The target endpoint is obliteration of the varix confirmed by hardening on palpation.

Equipment Precautions

•       Use non-reusable injection needles — NBCA will permanently bond to metallic/reusable equipment.

•       Avoid contact with metal surfaces, gloves (latex reacts), and water — polymerisation begins immediately on moisture contact.

•       Prepare and inject quickly — once mixed with lipiodol, use within the manufacturer's stated window.

Procedure-related Effects

•       Transient fever (within 24 hours) — due to inflammatory response to the adhesive cast.

•       Chest pain, dysphagia — if adhesive migrates proximally.

•       Abdominal pain at the injection site.

Serious Complications

•       Systemic embolism — inadvertent entry of NBCA into the systemic circulation, causing pulmonary, cerebral, or splenic emboli. Risk is higher with too-rapid injection or incorrect technique.

•       Needle tract adhesion — if the needle is not withdrawn promptly, it may bond to the mucosa, requiring endoscopic management.

•       Ulceration at injection site — the adhesive cast may cause local mucosal ulceration as it is shed; risk of delayed bleeding from the ulcer.

•       Rebleeding from incompletely obliterated varices.

•       Allergic reaction to cyanoacrylate (rare).

Systemic Embolism Prevention

The most feared complication is systemic embolism. Risk is reduced by: using appropriate NBCA: lipiodol ratios to slow polymerisation; injecting slowly; limiting injection volume per session; and using fluoroscopic guidance for interventional procedures. Emergency response plans for pulmonary embolism must be in place before performing the procedure.

Operator Training

Cyanoacrylate injection is a technically demanding procedure with a steep learning curve. It should only be performed by operators with documented training and sufficient case volume. Proctored training is recommended before independent practice.

Portal Hypertension Context

Patients requiring gastric variceal injection typically have decompensated liver cirrhosis with coagulopathy and thrombocytopenia. Periprocedural management of coagulation status (FFP, vitamin K, platelet transfusion) may be required and should be coordinated with the hepatology team.

As a topically injected tissue adhesive with no systemic absorption under normal use, systemic drug interactions are not applicable.

•       Anticoagulants (warfarin, heparin, DOACs) — will be present in the patient's blood and may affect haemostasis at the injection site; optimal anticoagulation management before the procedure is required.

•       Lipiodol (used as diluent/carrier) — an iodinated oily contrast agent; patients with iodine allergy may react; inform the radiologist.

•       Store below 25 degrees Celsius, protected from light and moisture.

•       Keep in original sealed vial — moisture exposure initiates polymerisation and ruins unused product.

•       Do not freeze.

•       Single-use only — discard any unused portion immediately after opening.

•       Keep out of reach of children.

ENDOCRYL is a hospital-use-only product in Kenya, available exclusively through specialist gastroenterology and interventional radiology units. It requires specialist authorisation and is not dispensed at community pharmacies.

Procurement and storage are managed at the institutional level. Its use must be documented in procedure records.

NBCA: Lipiodol Ratio Selection

The polymerisation time is inversely proportional to the NBCA concentration. Typical ratios: 1:1 NBCA: lipiodol (fast set, 1–2 seconds) for active bleeding; 1:2 (set time 3–5 seconds) for elective injection of non-bleeding varices. Adjust ratio based on variceal size, blood flow velocity, and operator preference.

Post-procedure Monitoring

•       Monitor vital signs, oxygen saturation for a minimum of 4 hours post-procedure.

•       Chest X-ray and pulse oximetry if any respiratory symptoms develop (pulmonary embolism screening).

•       Haemoglobin at 6 and 24 hours post-procedure.

•       Follow-up endoscopy at 4–6 weeks to assess variceal obliteration and manage adhesive cast ulcers.

Compared to Band Ligation

Oesophageal varices: band ligation is first-line. Gastric varices (especially fundal varices GOV2, IGV): NBCA injection is superior to band ligation and sclerotherapy due to the high-flow nature of gastric varices — NBCA is the preferred technique per AASLD and BSG guidelines.

What is cyanoacrylate and why is it used for stomach varices?

Cyanoacrylate is a medical-grade adhesive (similar in principle to super glue but formulated for biological use) that sets instantly on contact with blood. When injected into a varicose vein in the stomach, it forms a solid plug that blocks the vein and stops bleeding. It is particularly effective for gastric varices where other techniques like rubber banding are less successful.

How will I feel after the injection procedure?

Most patients experience mild discomfort or warmth in the upper abdomen for 24–48 hours after the procedure. A low-grade fever is common as the body responds to the adhesive. 

Will I need more injections in the future?

Possibly. A follow-up endoscopy is usually arranged 4–6 weeks after the procedure to check if the varices are fully obliterated. If residual or recurrent varices are found, further injections may be recommended.