Aspirin (acetylsalicylic acid) is a widely used nonsteroidal anti-inflammatory drug (NSAID) taken for pain relief, inflammation reduction, and is often prescribed in low doses to prevent cardiovascular events due to its anti-clotting properties. While highly beneficial for many people, aspirin carries a recognized and serious risk of causing gastrointestinal (GI) bleeding, which can become life-threatening. Understanding the dual mechanism of how aspirin injures the stomach lining is the first step in appreciating the potential for internal bleeding. This knowledge, combined with the ability to identify symptoms and take immediate action, is essential for anyone who takes this common medication.
How Aspirin Damages the Stomach Lining
Aspirin causes injury to the gastric mucosa through a combination of two distinct pathways: one topical and one systemic. The direct, local irritation occurs when aspirin tablets dissolve in the stomach, where the drug is present in a high concentration. The acidic nature of aspirin disrupts the protective mucosal barrier, allowing stomach acid to reach and injure the underlying epithelial cells. This direct cellular damage can lead to visible erosions and microbleeding on the stomach’s surface.
The systemic mechanism involves aspirin irreversibly inhibiting cyclooxygenase-1 (COX-1), an enzyme responsible for producing protective prostaglandins. These prostaglandins play a vital role in maintaining the stomach’s defenses by stimulating the secretion of mucus and bicarbonate, and by regulating blood flow to the gastric lining. By blocking COX-1, aspirin reduces the production of these protective factors, making the stomach more vulnerable to acid attack and inhibiting the natural healing process. This dual action ultimately leads to the formation of ulcers that are prone to bleeding, especially since aspirin also interferes with the blood’s ability to clot.
Identifying the Symptoms of Internal Bleeding
Recognizing the signs of active or recent internal bleeding is important, as the symptoms can range from subtle to immediately alarming. One of the most overt signs of upper GI bleeding is hematemesis, which is the vomiting of blood. This can appear as bright red blood if the bleeding is rapid and fresh, or as dark, granular material resembling “coffee grounds” if the blood has been partially digested by stomach acid.
Another key indicator is melena, characterized by black, sticky, and tarry-looking stools with a distinctive foul odor. This dark coloration results from blood moving through the upper digestive tract, where it is oxidized and chemically altered. It typically takes approximately 50 to 100 milliliters of blood loss in the upper GI tract to cause melena.
Beyond these visible signs, internal bleeding can also manifest through systemic symptoms related to blood loss and anemia. People may experience unexplained fatigue, generalized weakness, or pallor (unusual paleness). More serious signs, indicating a significant drop in blood volume, include dizziness, lightheadedness, shortness of breath, or a feeling of fainting. Any combination of these symptoms, particularly the visible signs of blood, warrants immediate medical evaluation.
Emergency Actions for Suspected Bleeding
If you suspect you are experiencing stomach bleeding related to aspirin use, the immediate actions you take before professional medical help arrives are crucial. The first step is to immediately stop taking the aspirin or any other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen. You must also refrain from taking any other blood-thinning medications.
The next step is to call for emergency medical services immediately, especially if you are vomiting blood, passing black or bloody stools, feel faint, or have severe abdominal pain. While waiting for first responders, remain calm and avoid eating or drinking anything, as this can worsen the bleeding or interfere with potential emergency procedures. If you are taking aspirin for a condition like a recent heart attack or stroke, the decision to stop the medication is complex, but in the setting of overt, severe GI bleeding, the immediate priority is to control the hemorrhage.
Once help arrives, be prepared to clearly communicate your symptoms, the amount of blood loss, and your complete medical history, including the exact dosage of aspirin and any other medications you take. Do not attempt to drive yourself to the hospital if you are experiencing significant systemic symptoms like dizziness or feeling faint, as this puts you and others at risk.
Professional Medical Treatments
Upon arrival at the hospital, the initial focus of treatment is on stabilization and resuscitation, especially if the bleeding has caused a significant drop in blood volume. This often involves administering intravenous (IV) fluids to restore circulating volume and potentially a blood transfusion to maintain hemoglobin levels, typically targeting a concentration above 7 g/dL in most people.
A high-dose regimen of Proton Pump Inhibitors (PPIs) is administered intravenously to suppress stomach acid production. This helps slow the bleeding and promotes clot stability. A common regimen involves an initial 80-milligram IV bolus followed by a continuous infusion of 8 milligrams per hour for up to 72 hours. This acid suppression is maintained even before the source of the bleeding is confirmed.
The definitive procedure to stop the bleeding is typically an urgent upper endoscopy, performed to identify the exact location and cause of the hemorrhage. During the endoscopy, the clinician can perform therapeutic interventions to achieve hemostasis. These include injection therapy using epinephrine, thermal coagulation to cauterize the bleeding vessel, or mechanical methods such as applying endoscopic clips. In rare cases where endoscopic methods fail or the bleeding is severe and persistent, surgical intervention may be required to control the hemorrhage.
Preventing Future Aspirin-Related Bleeding
After the acute bleeding episode is managed, a long-term strategy must be developed in consultation with a physician to prevent recurrence, particularly if aspirin therapy must be continued for cardiovascular health. Optimizing the aspirin regimen may involve reducing the dosage to the lowest effective dose for the specific medical need. Taking aspirin with food or a full glass of water can help minimize the direct topical irritation to the stomach lining.
While enteric-coated aspirin is designed to dissolve in the small intestine rather than the stomach, thereby reducing initial topical irritation, it does not eliminate the systemic risk. The systemic mechanism of damage through COX-1 inhibition and subsequent prostaglandin reduction remains, and enteric-coated aspirin can still cause injury further down the GI tract. Therefore, a more robust preventative measure is often the co-prescription of a prophylactic medication.
The most common preventative approach is the long-term use of a low-dose Proton Pump Inhibitor (PPI), which provides sustained acid suppression to protect the healed stomach lining. PPIs have been shown to be superior to other options in preventing recurrent bleeding in people who must continue taking aspirin. Alternatively, for people who cannot tolerate PPIs, misoprostol, a synthetic prostaglandin analog, may be prescribed, as it helps restore the stomach’s protective mucus and bicarbonate layer.