What Is Involved in the Metabolism of Aspirin?

Bamil tablets are also known as water-soluble acetylsalicylic acid tablets. This product is an antipyretic, analgesic, anti-inflammatory, anti-rheumatic, and platelet aggregation inhibitor. For fever (cold, flu, etc.), pain (headache, toothache, neuralgia, muscle pain, dysmenorrhea, etc.), rheumatism (rheumatoid arthritis, rheumatoid arthritis), and prevention of transient ischemic attacks, Thrombosis after myocardial infarction or other surgery.

Acetylsalicylic acid tablets

Bamil tablets are also known as water-soluble acetylsalicylic acid tablets. This product is an antipyretic, analgesic, anti-inflammatory, anti-rheumatic, and platelet aggregation inhibitor. For fever (cold, flu, etc.), pain (headache, toothache, neuralgia, muscle pain, dysmenorrhea, etc.), rheumatism (rheumatoid arthritis, rheumatoid arthritis), and prevention of transient ischemic attacks, Thrombosis after myocardial infarction or other surgery.

Drug Name

Acetylsalicylic acid tablets

Whether prescription drugs

Non-prescription drugs

Athletes use with caution

Inadvertent use

Whether to include health insurance

Incorporate

Aspirin tablets (1) 0.075g (2) 0.3g (3) 0.58g

(1). Antipyretic and analgesic: 0.3-0.6g each time, 3 times a day, or when needed.

(2) .Anti-rheumatic: 0.5-1g each time, 3-5 times a day, should be chewed when taken, can be combined with calcium carbonate, aluminum hydroxide or Weishuping, a course of 3 months; children 0.1g / kg a day Take 3 doses and reduce the response with half the amount for the first 3 days.

(3) Prevention of thrombosis, atherosclerosis and myocardial infarction: 0.3 / time, once a day; Prevention of temporary cerebral ischemia, 0.6g each time, twice a day.

(4). Treatment of biliary tapeworm: 1g each time, 2-3 times a day, even for 2-3 days.

(5). For diarrhea caused by X-ray irradiation or radiotherapy, take 0.6-0.9g each time, 4 times a day.

(6). For treating athlete's foot, first wash it with warm boiling water or 1: 5000 potassium permanganate solution, and then spread the affected area with powder of this product, usually 2-4 times. The half-life is long, the opposite is the case at night. The reasonable dosage should be slightly increased in the morning. Take an additional dose in the evening. (Xu Shuyun: Anhui Medicine. 1984.)

Salicylic acid analgesics, anti-inflammatory, antipyretic, anti-rheumatic, and platelet aggregation inhibitors can be used clinically in the following situations.

(1) Analgesic and antipyretic: It can relieve mild or moderate pain, such as headache, toothache, neuralgia, muscle pain and menstrual pain. It is also used for antipyretics such as cold and flu. This product can only relieve symptoms and cannot treat the causes of pain and fever, so other drugs should be used at the same time.

(2) Anti-inflammatory and anti-rheumatic: it is the drug of choice for the treatment of rheumatic fever. After treatment, it can relieve fever, reduce inflammation, improve joint symptoms, and decrease blood sedimentation, but it cannot remove the basic pathological changes of rheumatism, prevent heart damage and other complications disease. If there is obvious myocarditis, it is generally advisable to use adrenal corticosteroids first. After rheumatic symptoms are controlled and before hormones are stopped, add this product to reduce the rebound phenomenon caused by hormones.

(3) Arthritis: In addition to rheumatoid arthritis, this product is also used to treat rheumatoid arthritis, which can improve symptoms and create conditions for further treatment. In addition, this product is used for osteoarthritis, ankylosing spondylitis, juvenile arthritis, and other non-rheumatic inflammation of skeletal muscle pain, which can also relieve symptoms.

(4) Antithrombotic: This product can inhibit platelet aggregation and prevent thrombosis. It can be used clinically to prevent temporary ischemic attack, myocardial infarction, atrial fibrillation, artificial heart valve, arteriovenous fistula or other postoperative thrombosis. . Can also be used to treat unstable angina.

* 5. Pediatrics is used for the treatment of cutaneous mucosal lymph node syndrome (Kawasaki disease).

1. Adults usually take it orally. Antipyretic and analgesic, 0.3-0.6g once, 3 times a day, and once every 4 hours if necessary. Resist rheumatism, 3-5g a day (7-8g for acute rheumatic fever), orally divided into 4 times. Inhibit platelet aggregation, there is no clear dosage, most of them advocate the use of small doses, such as 50-150mg, once every 24 hours. For treatment of biliary tsutsugamushi, 1g at a time, 2-3 times a day, and 2-3 days in a row; paroxysmal colic should be discontinued after 24 hours, and then deworming treatment should be performed.

2. Commonly used in children. Antipyretic and analgesic, orally at a daily surface area of 1.5g / m2, 4 to 6 times a day, or 5-10mg / kg each time, or 60mg per year, 4-6 hours if necessary1 Times: Resist rheumatism, take 80 to 100 mg / kg daily, divided into 3 to 4 times. If no effect is obtained in 1-2 weeks, the dosage can be adjusted according to blood concentration. Some cases need to increase to 130mg / kg daily.

Others: Pediatrics are used for skin and mucosal lymph node syndrome (Kawasaki disease), starting at 80-100 mg / kg per day, divided into 3 to 4 servings, and changed to 30 mg / kg per day after 2 to 3 days of heat regression, divided into 2 Take 4 times, even for 2 months or longer, during the period of thrombocytosis and blood coagulation, 5-10mg / kg daily, once serving.

1. For those who are frail or whose temperature is above 40 , a small amount should be used when antipyretic, so as not to sweat a lot and cause collapse. You should drink plenty of water during antipyretics to facilitate perspiration and cool down, otherwise water and electrolyte balance imbalance or collapse due to excessive sweating.

2. Sometimes nausea and vomiting are seen. Larger oral doses (more than 3g per day) can stimulate the stomach, destroy the gastric mucosal barrier and cause gastric bleeding, and reduce systemic bleeding due to reducing prothrombin, as can be prevented by taking vitamin K (2 to 4 mg daily).

3. People with specific constitution can cause allergic reactions such as rash, angioedema, and asthma. Among them, asthma is most common (about 2/3), so it should be used with caution in asthma patients.

4. Patients with gastric and duodenal ulcer disease should be used with caution or not. If necessary, they should be taken with antacids (such as Wei Shuping or magnesium trisilicate) or enteric-coated tablets.

5. Do not take this product before or after drinking, because it can damage the gastric mucosal barrier and cause bleeding.

6. Taking a large amount or taking a large amount by mistake for a long time can cause acute poisoning. The symptoms are headache, dizziness, tinnitus, vision loss, vomiting, a lot of sweating, delirium, and even high fever, dehydration, collapse, coma and endanger life.

7. When combined with other salicylic acid drugs, dicoumarin anticoagulants, sulfa drugs, hypoglycemic drugs, barbiturates, phenytoin, methotrexate, etc., they can enhance their effects and toxicity .

8. Because glucocorticoids can stimulate gastric acid secretion and reduce the gastric and duodenal mucosa's resistance to gastric acid, combined use with this product may exacerbate gastrointestinal bleeding.

9. Combining this product with aminophylline or other alkaline drugs (such as sodium bicarbonate) can promote excretion of this product and reduce its efficacy.

10. This product significantly reduces the blood concentration of non-steroidal anti-inflammatory drugs such as ibuprofen, and the two should not be used in combination.

11, can cause fetal abnormalities, women during pregnancy try to avoid using. ^[1]

Analgesic effect: mainly by inhibiting the synthesis of prostaglandins and other substances (such as bradykinin, histamine) that can make the pain sensitive to mechanical or chemical stimuli, which belongs to peripheral analgesics. However, the possibility of central analgesia (which may act on the hypothalamus) cannot be ruled out; anti-inflammatory effect; the exact mechanism is not clear, it may be because this product acts on inflammatory tissues, by inhibiting prostaglandins or other substances that can cause inflammatory reactions The synthesis of substances (such as histamine) plays an anti-inflammatory role, and may inhibit the release of lysosomal enzymes and leukocyte vitality. Antipyretic effect: It may cause peripheral vasodilatation by acting on the hypothalamus temperature regulating center, skin Increased blood flow, sweating, and increased heat dissipation play an antipyretic effect. This central effect may be related to the inhibition of prostaglandin synthesis in the hypothalamus; Anti-rheumatic effect: The anti-rheumatic mechanism of this product eliminates heat, In addition to the analgesic effect, it mainly lies in the anti-inflammatory effect. The inhibitory effect on platelet aggregation: it inhibits the production of thromboxane A2 (thromboxane A2TXA2) by inhibiting platelet prostaglandin cyclooxygenase (TXA2 can Promote platelet aggregation). This effect is irreversible.

It is absorbed quickly and completely after oral administration. Absorption has begun in the stomach, and most of it can be absorbed in the upper small intestine. Absorption is related to solubility and gastrointestinal pH. Food reduces the rate of absorption, but does not affect the amount absorbed. Enteric-coated tablets absorb slowly. This product absorbs quickly when taken with sodium bicarbonate. After absorption, it is distributed in various tissues and can also penetrate into the joint cavity and cerebrospinal fluid. Aspirin has a low protein binding rate, but the salicylate protein binding rate after hydrolysis is 65-90%. When the blood concentration is high, the binding rate decreases accordingly. Renal dysfunction and the rate of administration during pregnancy are also low. The half-life is 15-20 minutes; the half-life of salicylate depends on the size of the dose and the pH of the urine. It is about 2 to 3 hours when a small dose is taken once; 5 to 18 hours. After oral aspirin 0.65g, the salicylate half-life in breast milk was 3.8 to 12.5 hours. This product is mostly hydrolyzed to salicylate in the gastrointestinal tract, liver and blood, and then metabolized in the liver. The metabolites are mainly salicyluric acid and glucuronic acid conjugates, a small part of which is oxidized to gentisic acid. Peak blood drug was reached 1 to 2 hours after a single dose. The blood drug concentration is 25-50 g / ml when analgesic and antipyretic; 150-300 g / ml when anti-humidity and anti-inflammatory. The time required for the blood drug concentration to reach a steady state increases with the daily dose and blood drug concentration, and it can be as long as 7 days when the drug is administered in large doses (such as anti-rheumatic). For long-term high-dose patients, because the main metabolic pathways of the drug have been saturated, a slight increase in dose can lead to large changes in blood concentration. Most of this product is excreted from the kidneys as a combined metabolite and a small part as free salicylic acid. When the dose is large, excretion of unmetabolized salicylic acid increases. Individuals can vary greatly. The pH of urine has an effect on the rate of excretion. Excretion rate is accelerated in alkaline urine, and the amount of free salicylic acid is increased. The opposite is true in acid urine.

(1) Cross-allergic reactions. Allergic to this product may also be allergic to another salicylic acid. However, people who are allergic to this product may not be allergic to non-acetylated salicylic acids.

(2) This product easily passes through the placenta. Animal tests in the first 3 months of application of this product can cause teratomy, such as spina bifida, skull fissure, facial fissure, leg deformities, and central nervous system, visceral and skeletal hypoplasia. Fetal defects have also been reported in humans after application of this product. In addition, the long-term application of this product in the third trimester of pregnancy can prolong the pregnancy and increase the risk of postpartum syndrome and prenatal bleeding. Application in the last 2 weeks of pregnancy can increase the risk of fetal bleeding or neonatal bleeding. Long-term use in late pregnancy may also cause fetal arterial ducts to contract or lock up early, leading to persistent pulmonary hypertension and heart failure in the newborn. Excessive application or abuse in late pregnancy has increased the incidence of stillbirths or neonatal deaths (possibly due to arterial catheter occlusion, prenatal bleeding, or low body weight), but the above-mentioned side effects have not been found in general therapeutic doses.

(3) This product can be excreted in breast milk. Breastfeeding women take 650 mg orally. After 5-8 hours, the drug concentration in breast milk can reach 173-483 g / ml. Therefore, infants may have adverse reactions during long-term high-dose medication.

(4) Elderly patients are prone to toxic reactions when taking this product.

(5) Pediatric patients, especially those with fever and dehydration, are prone to toxic reactions. Acute febrile diseases, especially in children with influenza and chickenpox, may be related to the occurrence of Reye's syndrome, which is rare in China.

(6) The following conditions should be disabled: ulcers with bleeding symptoms or other active bleeding; hemophilia or thrombocytopenia.

(7) It should be used with caution in the following cases: when there is asthma and other allergic reactions; ulcer disease or corrosive gastritis; glucose 6 phosphate dehydrogenase deficiency (this product occasionally causes hemolytic anemia); gout (This product can affect the effects of other uric acid drugs, which may cause uric acid retention at low doses); Hepatic dysfunction can aggravate liver toxic reactions and exacerbate bleeding tendency; patients with liver dysfunction and cirrhosis are prone to kidney adverse reactions; Cardiac insufficiency or high blood pressure may cause heart failure or pulmonary edema when used in large amounts; Renal failure may increase the risk of renal toxicity.

Children under 12 years of age may cause Reye's syndrome, hyperuricemia, and long-term use can cause liver damage. Avoid use in pregnant women. Drinking aspirin in a therapeutic amount can cause spontaneous anterior chamber hemorrhage, so patients with traumatic anterior chamber hemorrhage should not use aspirin. Aspirin is contraindicated in patients with caesarean or abortion; aspirin worsens hemolysis in patients with hemolytic anemia with glucose 6-phosphate dehydrogenase deficiency; newborns, young children, and the elderly appear to be particularly sensitive to aspirin-induced bleeding. The therapeutic dose can cause metabolic acidosis, fever, excessive ventilation and brain symptoms in children under 2 years of age;

It should be taken with food or washed with water to reduce gastrointestinal irritation; The whole piece should be swallowed within 7 days after tonsillectomy or oral surgery to avoid touching the wound after chewing and causing injury; Surgical patients should Discontinued 5 days before surgery. In order to avoid causing coagulopathy; When used for the treatment of arthritis, the dose should be gradually increased until the symptoms are relieved and the effective blood concentration is reached (at this time, mild toxic reactions such as tinnitus and headache may occur, in children, elderly or deaf patients (These symptoms are not reliable indicators.) Begin to reduce the dose; but the dosage should not be adjusted frequently, generally not more than once a week, of course, if there are side effects, it should be quickly reduced; the salicylic acid drug has reached a steady state in blood concentration. It takes 7 days; patients with dehydration (especially children) should reduce the dose.

Regular long-term use of drugs should be checked regularly for hematocrit, liver function, and determination of serum salicylic acid.

The dosage generally used for antipyretic analgesia rarely causes adverse reactions. Long-term heavy medication (such as treatment of rheumatic fever), especially when the blood concentration of the drug is> 200 g / ml, side effects are more likely to occur. The higher the blood concentration, the more obvious the side effects.

(1) There are more common gastrointestinal reactions (incidence rate 3-9%) such as nausea, vomiting, upper abdominal discomfort or pain (due to the direct stimulation of gastric mucosa by this product).

(2) Rare or rare (incidence rate <3%); gastrointestinal bleeding or ulcers, manifested as bloody or tarry stools, severe stomach pain or vomiting bloody or coffee-like substances, more common in Patients taking large doses; it is reported that 70% of those taking 4-6g per day bleed 3-10ml per day, and those with ulcers can bleed more and can cause hemorrhagic anemia; enteric-coated tablets rarely have gastrointestinal irritation Reaction; bronchospasm allergic reaction, manifested as shortness of breath, dyspnea or asthma, chest tightness; skin allergic reaction, manifested as rash, urticaria, itching of the skin, etc .; liver and kidney function damage is related to the size of the dose, especially It is easy to occur when the dosage of Ambassador blood drug reaches 250g / ml. The damage is reversible and can be recovered after stopping the drug.

(3) Overdose or poisoning manifestations: Mild, that is, salicylism, is more common in rheumatoid patients treated with this product, and manifests as headache, dizziness, tinnitus, deafness, nausea, vomiting, diarrhea, drowsiness, Mental disorders, sweating, breathing fast, thirst, involuntary movements of hands and feet (most common in the elderly), visual impairment, etc .; Severe, hematuria, convulsions, hallucinations, severe mental disorders, dyspnea, unknown fever, etc .; Children's mental and respiratory disorders are more pronounced; laboratory tests may show abnormal EEG, changes in acid-base balance (respiratory alkalosis and metabolic acidosis), hypoglycemia or hyperglycemia, ketonuria, hyponatremia when overdose , Hypokalemia and proteinuria.

Can cause gastrointestinal irritation, bleeding or discomfort, hemolytic anemia, interference with platelet function, angioedema, rash, asthma, overdose and dizziness, tinnitus, sweating, nausea, vomiting, mental disorders or disorders, excessive replacement Qi, unconsciousness, cardiogenic collapse, dyspnea. Children under 12 years of age may cause Reye's syndrome, hyperuricemia, and long-term use can cause liver damage.

(1) The effect is not enhanced when used with other non-steroidal anti-inflammatory analgesics, and the gastrointestinal side effects (including ulcers and bleeding) are increased; in addition, as the inhibitory effect on platelet aggregation is strengthened, bleeding in other parts can also be increased danger. Long-term use of this product with acetaminophen may cause kidney disease.

(2) When used together with any drug that can cause hypothrombinemia, thrombocytopenia, reduced platelet aggregation, or gastrointestinal ulcer bleeding, there may be a risk of exacerbating coagulation disorders and causing bleeding.

(3) Used together with anticoagulants (dicoumarin, heparin, etc.) and thrombolytic drugs (streptokinase, urokinase), it can increase the risk of bleeding.

(4) Urine alkalizing drugs (sodium bicarbonate, etc.) and antacids (long-term large-scale application) can increase the excretion of this product from the urine and reduce the blood concentration. However, when the blood concentration of this product has reached a stable state and the alkaline drug is stopped, the blood concentration of this product can be raised to a toxic level. Carbonic anhydrase inhibitors can make urine alkaline, but can cause metabolic acidosis, which not only can reduce the blood concentration, but also increase the amount of this product penetrated into the brain tissue, thereby increasing the toxicity.

(5) Uric acid drugs can reduce the excretion of this product and increase its blood concentration. The addition of uric acid to patients whose blood concentration of this product has reached a stable state may lead to an increase in the blood concentration of this product and an increase in toxicity.

(6) Glucocorticoids (hormones for short) can increase the excretion of salicylate. In order to maintain the blood concentration of this product, the dosage of this product should be increased when necessary. This product is used together with hormones for a long time, especially when it is used in large quantities, salicylism may occur when the hormone is reduced or discontinued, and it may even increase the risk of gastrointestinal ulcers and bleeding.

(7) The hypoglycemic effect of insulin or oral hypoglycemic drugs can be strengthened and accelerated due to the use with a large amount of this product.

(8) When used together with methotrexate (MTX), it can reduce the combination of methotrexate and protein, reduce its excretion from the kidney, increase the blood concentration and increase the toxic response.

(9) The uric acid effect of probenecid or sulfinpyrazone can be reduced by the simultaneous application of this product; when the salicylate blood concentration is> 50 g / ml, the decrease is obvious,> 100-150 g / Even worse for ml. In addition, probenecid can reduce salicylate clearance from the kidneys, thereby increasing the plasma concentration of the latter.

It is used in combination with other non-hormonal anti-inflammatory drugs or glucosteroids to enhance the stimulating effect on the stomach. Hormones have some effects of lowering the salicylic acid concentration. If the hormone is stopped after the two are combined, the salicylic acid concentration in the blood will increase and become poisoned. It has the effect of strengthening methotrexate, sulfa and valproic acid. It reduces the antihypertensive effect of Captopril. When treating glaucoma with a carbonic anhydrase inhibitor, aspirin can promote metabolic acidosis. Alcohol can prolong the bleeding time and stomach bleeding caused by aspirin. It cannot be used in combination with anticoagulants.