Aspirin is a salicylate. It works by reducing substances in the body that cause pain, fever, and inflammation, aspirin is used to treat pain, and reduce fever or inflammation. It is sometimes used to treat or prevent heart attacks, strokes, and chest pain (angina). Aspirin should be used for cardiovascular conditions only under the supervision of a doctor. Aspirin was first drug that chemically synthesis by Bayer.
It is available under a number of trade names, including Arthritis Pain, Aspi-Cor, Aspir 81, Aspir-Low, Bayer Plus, Bufferin, Durlaza, Ecotrin, Ecpirin, Miniprin.
Drug Fact
Class : NSAID
Category : Over The Counter (OTC) drug
Uses : treat pain, and reduce fever or inflammation. It is sometimes used to treat or prevent heart attacks, strokes, and chest pain (angina).
Consumed by : Aspirin used in adults
Pregnancy category : C and D
Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocide or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Dosage form : tablet
Administration
Should be taken with food.
Contraindications
Hypersensitivity to aspirin or other NSAIDs. Peptic ulcer, haemorrhagic disease, coagulation disorder (e.g. haemophilia, thrombocytopenia), gout. Severe hepatic and renal impairment. Children <16 years and recovering from viral infection. Pregnancy (doses >100 mg daily during 3rd trimester) and lactation. Concomitant use with other NSAIDs and methotrexate.
Special Precautions
Patient with dyspepsia or lesion of the GI mucosa, asthma or allergic disorders, anaemia, dehydration, menorrhagia, uncontrolled hypertension, G6PD deficiency, thyrotoxicosis. Patients undergoing surgical procedures. Moderate hepatic and renal impairment. Pregnancy.
Adverse Reactions
Significant: Salicylate sensitivity, tinnitus.
Blood and lymphatic system disorders: Anaemia, hypoprothrombinaemia, thrombocytopenia.
Gastrointestinal disorders: Dyspepsia, gastric irritation, nausea, vomiting.
Nervous system disorders: Dizziness, confusion.
Respiratory, thoracic and mediastinal disorders: Asthma, bronchospasm, dyspnea, rhinitis.
Skin and subcutaneous tissue disorders: Rash, urticaria.
Potentially Fatal: Paroxysmal bronchospasm and dyspnoea. Coma, CV collapse, resp failure, severe hypoglycaemia. Rarely, Reye’s syndrome. Hypersensitivity reactions (e.g. Stevens Johnson syndrome, angioedema), gastrointestinal bleeding and perforation.
Overdosage
Symptoms: Vomiting, dehydration, tinnitus, vertigo, deafness, sweating, warm extremities with bounding pulses, increased respiratory rate, hyperventilation, acid-base disturbance, haematemesis, hyperpyrexia, hypoglycaemia, hypokalaemia, thrombocytopenia, increased INR/PTR, intravascular coagulation, renal failure, pulmonary oedema, CNS effects (e.g. confusion, disorientation, coma, convulsion). Management: Administer activated charcoal if patient presents ingestion of >250 mg/kg within 1 hr. Perform urinary alkalinisation by administration of 1.26% Na bicarbonate then monitor urine pH. Correct metabolic acidosis with 8.4% Na bicarbonate IV. For severe poisoning (plasma conc: >700 mg/L), haemodialysis is the treatment of choice.
Drug Interactions
Increased risk of GI bleeding and ulceration with corticosteroids. Increased risk of bleeding with coumarin anticoagulants (e.g. heparin, warfarin, phenindione) and antiplatelet agents (e.g. clopidogrel, dipyridamole). May result in severe acidosis and increased CNS toxicity with carbonic anhydrase inhibitors (e.g. acetazolamide). Increases the hypoglycaemic effect of sulfonylureas. Reduces binding of phenytoin and valproate to serum albumin leading to increased free concentration of the drugs. Reduces the effect of uricosurics (e.g. probenecid, sulfinpyrazone). Impairs the renal excretion of lithium and digoxin.
Potentially Fatal: Increased risk of GI bleeding and ulceration with other NSAIDs. Increased risk of haematological toxicity of methotrexate.
Food Interaction
Increased risk of GI bleeding with alcohol. Reduced GI irritation with admin of food and large quantity of water or milk.
Lab Interference
Interferes with thyroid function, Gerhardt, VMA determination, 5-HIAA, and xylose tolerance tests. False negative result for glucose oxidase urinary glucose test; false positive in cupric sulfate method.
Action
Description: Aspirin is a salicylate that exhibits analgesic, anti-inflammatory, and antipyretic activities. It is a selective and irreversible inhibitor of cyclooxygenase-1 (COX-1) enzyme resulting in direct inhibition of the biosynthesis of prostaglandins and thromboxanes from arachidonic acid. Additionally, it also inhibits platelet aggregation.
Synonym: acetylsalicylic acid (ASA).
Onset: Platelet inhibition: Within 1 hr (nonenteric-coated); delayed (enteric-coated); 20 minutes (if chewed).
Duration: 4-6 hours (immediate-release); Platelet inhibition: Approx 10 days.
Pharmacokinetics:
Absorption: Rapidly absorbed from the gastrointestinal tract; less reliable (rectal); absorbed through the skin. Partially hydrolysed by esterases to salicylate during absorption in the GI tract. Bioavailability: 50-75% (immediate-release). Time to peak plasma concentration: Approx 1-2 hours (nonenteric-coated); 3-4 hours (enteric-coated); Approx 2 hours (extended-release cap).
Distribution: Widely and rapidly distributed into most body tissues and fluids. Crosses the placenta and enters breast milk. Volume of distribution: 170 mL/kg. Plasma protein binding: 80-90%.
Metabolism: Metabolised in the liver into salicyluric acid, salicyl phenolic glucuronide, salicylic acyl glucuronide, gentisic acid, and gentisuric acid. Undergoes first-pass metabolism.
Excretion: Via urine (75% as salicyluric acid, 10% as salicylic acid). Elimination half-life: 15-20 minutes.
Chemical Structure
Storage
Store below 25°C.
ATC Classification
N02BA01 - acetylsalicylic acid ; Belongs to the class of salicylic acids and derivatives agents. Used to relieve pain and fever.
A01AD05 - acetylsalicylic acid ; Belongs to the class of other agents for local oral treatment.
B01AC06 - acetylsalicylic acid ; Belongs to the class of platelet aggregation inhibitors excluding heparin. Used in the treatment of thrombosis.
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