Aspirin is the most widely used drug in the world for pain relief. It has been used as an antiplatelet agent to prevent thrombosis and embolism and has been formulated as enteric-coated low-dose preparation for the prophylaxis and treatment of transient ischaemic attack (TIA) and other thromboembolic disorders.
Pharmacology: Aspirin is an analgesic, anti-inflammatory, antipyretic and an inhibitor of platelet aggregation. It acetylates the enzyme cyclooxygenase, thereby inhibiting the synthesis of prostaglandins, thromboxane in the circulation, platelets and prostacyclin in the systemic vascular endothelium. Thromboxane is a vasoconstrictor and inhibitor of platelet aggregation.
The antiplatelet aggregating effect of Casprin is postulated to retard or reduce the development of thromboembolic disorders. The low dose, enteric-coated and relatively slow rate of release of aspirin is observed to selectively and irreversibly inhibit thromboembolic synthesis. Aspirin inhibits thromboxane synthesis in the portal circulation and is presystemically metabolised to salicylate with negligible amount reaching the systemic circulation to inhibit prostacyclin synthesis. Salicylate is effectively inactive at the blood concentrations achieved clinically and prostacyclin is less sensitive than thromboxane to aspirin.
Pharmacokinetics: In order to eliminate the gastrointestinal adverse effects of aspirin, an enteric-coated, low-dose aspirin (as pellets) was developed. The advantages of enteric-microencapsulated capsules include ready distribution over a large area, thus minimizing the risk of local damage caused by the dumping effect of enteric-coated tablets. Furthermore, enteric-microencapsulated capsules are also less dependent on gastric transient time. They may attain more constant plasma level, achieve slow-release effect, give higher accuracy in reproducibility between doses and provide less decreases in bioavailability.
Following oral administration, absorption of aspirin occurs in the intestine. Some aspirin is hydrolysed to salicylate in the gut wall. Aspirin is bound to plasma protein and is widely distributed. Plasma aspirin concentrations decline rapidly (half-life: 15-20 min) as plasma salicylate concentrations increases.
Aspirin is rapidly converted by esterases present in plasma and many tissues, especially the liver, to salicylic acid which itself has some antipyretic, analgesic and anti-inflammatory actions but which has little effects on platelets. Salicylic acid is metabolised in the liver to the glycine conjugate salicyluric acid. Other metabolites include salicyl phenolic glucuronide; salicyl acyl glucuronide and gentisic acid. Excretion of salicylic acid in urine is pH-dependent; approximately 80% appears unchanged in urine at pH 8, but only around 10% at pH 4.
Since enteric-coated pellets of aspirin can reduce gastrointestinal side effects that may occur with conventional or other enteric-coated tablet preparations, it is an effective antiplatelet treatment of choice for long-term treatment and prevention of certain forms of ischaemic attacks.
Treatment of acute myocardial infarction (heart attack), prevention of heart attack in certain high-risk group patients and for prevention of stroke after transient ischaemic attacks (TIA).
1 cap daily to be taken with a glass of water.
Symptoms: Mild cases may produce nausea, vomiting, sweating, thirst and tachycardia. Severe overdosage may show fever and CNS disturbances, eg convulsions, hallucinations, coma and respiratory failure.
Treatment: Management includes gastric lavage and emesis for mild cases; in severe cases, barbiturate administrations or dialysis may be required.
Patients who are allergic to aspirin.
Patients with severe hepatic and renal disease, haemophilia or other bleeding disorders, erosive gastritis or peptic ulcers.
Because of its relatively low dosage and enteric-coating dosage form, the risk of Casprin in causing gastrointestinal ulceration is greatly reduced. However, care should be taken in administering Casprin to patients with prior history of serious gastrointestinal events.
Concurrent use of Casprin with alcoholic beverages should be avoided in order to avoid gastrointestinal toxicity.
Care should be taken when aspirin us administered to asthmatic patients.
Caution is necessary when renal or hepatic function is impaired.
Use in pregnancy: Animal studies have shown that aspirin can cause birth defects in numerous species. There is no conclusive evidence that aspirin causes malformation in humans. Drugs, eg aspirin inhibit prostaglandin synthesis. When given late in pregnancy, it may cause premature closure of the fetal ductus arteriosus, prolong labour and delay birth. Aspirin increases the bleeding time both in the newborn infant and in the mother because of its antiplatelet effects. Products containing aspirin should be avoided in late pregnancy.
Use in children: The use of aspirin in children <16 years is not recommended because of the risk of Reye's syndrome.
Use in pregnancy: Animal studies have shown that aspirin can cause birth defects in numerous species. There is no conclusive evidence that aspirin causes malformation in humans. Drugs, eg aspirin inhibit prostaglandin synthesis. When given late in pregnancy, it may cause premature closure of the fetal ductus arteriosus, prolong labour and delay birth. Aspirin increases the bleeding time both in the newborn infant and in the mother because of its antiplatelet effects. Products containing aspirin should be avoided in late pregnancy.
The main adverse reactions associated with aspirin therapy include gastrointestinal distress, nausea, vomiting, erosion of the gastric mucosa, ulceration and occult blood loss.
Concurrent administration of aspirin and dipyridamole may result in an increase in peak plasma salicylate concentration and area under the curve.
Serum salicylate concentrations may be reduced by concurrent administration of corticosteroids.
Aspirin may enhance the activity of coumarin anticoagulant, sulfonylurea, hypoglycaemic agent, methotrexate, phenytoin and valproic acid.
Store at temperatures between 15°C and 30°C. Keep in an airtight container. Protect from light and moisture.
Shelf-Life: 2 years.
B01AC06 - acetylsalicylic acid ; Belongs to the class of platelet aggregation inhibitors excluding heparin. Used in the treatment of thrombosis.
Casprin EC cap 100 mg
24 × 30's;50 × 30's
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