Amicar bladder irrigation is a specialized medical approach used to stop severe bleeding within the bladder. The procedure involves continuously washing the bladder with a solution containing the drug Amicar, the trade name for aminocaproic acid. This technique manages hematuria, or blood in the urine, that is difficult to control with standard methods. The goal of this localized therapy is to stabilize blood clots forming on the bladder wall, which often break down prematurely in the urinary environment.
How Aminocaproic Acid Works
Aminocaproic acid (Amicar) is a synthetic derivative of the amino acid lysine. It functions as an antifibrinolytic agent, meaning its primary role is to prevent the breakdown of blood clots. The body’s natural process for dissolving clots is called fibrinolysis, which relies on the enzyme plasmin.
Plasmin is created from an inactive precursor called plasminogen by activators, such as urokinase, which is naturally present in the urine. Aminocaproic acid works by competitively binding to specific sites on plasminogen, known as lysine-binding sites. By occupying these sites, the drug prevents plasminogen from attaching to the fibrin structure of a forming clot.
This mechanism inhibits the conversion of plasminogen into the clot-dissolving enzyme plasmin, especially in the urinary tract where urokinase activity is high. This stabilizes the fibrin matrix, allowing the clot to remain intact at the site of bleeding on the bladder wall. Since the drug is administered via irrigation, the clot-stabilizing effect is concentrated locally in the bladder.
When This Treatment Is Necessary
Amicar bladder irrigation is indicated for severe, persistent hematuria when initial, less aggressive treatments have failed. The bleeding must originate from the bladder itself, as the drug can be harmful if used when bleeding occurs higher up in the urinary tract. The procedure is a targeted approach for hemorrhagic cystitis, characterized by inflammation and diffuse bleeding of the bladder lining.
This type of severe bleeding often necessitates Amicar irrigation. Specific causes include hemorrhagic cystitis caused by chemotherapy drugs, such as cyclophosphamide, or following pelvic radiation therapy. This latter condition, known as radiation cystitis, can cause long-term blood loss.
The treatment also manages delayed or recurrent bleeding following prostate surgery, such as a transurethral resection of the prostate, where excessive fibrinolysis may be dissolving surgical clots. Before starting Amicar, all existing large blood clots must be removed from the bladder, as the drug can make them extremely dense and difficult to pass.
The Irrigation Procedure Steps
The procedure requires inserting a specialized urinary catheter, most commonly a triple-lumen Foley catheter. This catheter has three channels: one for inflating the balloon, one for the inflow of the irrigation solution, and a large channel for the outflow of urine and fluid. The large outflow channel helps prevent obstruction from small clots.
The aminocaproic acid solution is prepared by mixing the drug with a sterile fluid, such as 0.9% sodium chloride, often at a concentration of around 200 mg of Amicar per liter of saline. This solution is delivered continuously into the bladder through the catheter’s inflow port. The continuous flow washes over the bladder wall and exits through the third lumen, carrying away blood and preventing new clot formation.
The flow rate is adjusted based on the severity of the bleeding and the color of the draining fluid. If the outflow remains dark red, the rate is increased; if it becomes clear or light pink, the rate is decreased. The procedure continues for a minimum of 24 hours after the urine output has become clear.
Safety Considerations and Side Effects
A primary concern is clot retention, which occurs when stabilized blood clots become too firm or large to pass through the catheter. These dense clots can obstruct the catheter, potentially leading to painful bladder over-distension. If this happens, manual removal or a surgical procedure may be necessary to clear the obstruction.
Although Amicar is administered locally, there is a low potential for systemic absorption into the bloodstream. Continuous monitoring is necessary to watch for signs of potential systemic side effects, which are rare with this localized treatment. These signs include a drop in blood pressure, muscle weakness, or an irregular heart rhythm.
Continuous nursing and medical oversight is necessary during the irrigation process to manage the flow rate and observe the patient for discomfort or bladder spasms. The goal is to control bleeding without causing an adverse reaction or an obstruction of the drainage system. Fluid balance must be meticulously tracked by calculating the true urine output (total output volume minus total irrigation fluid infused).