Aspirin: The wonder drug

Aspirin or salicyclate is a non-steroidal anti-inflammatory drug that works as a wonder drug. Its various aspects are:

1. Inhibition of Prostaglandin Synthesis and Antithrombotic action: Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the activity of the enzyme now called cyclooxygenase (COX) which leads to the formation of prostaglandins (PGs) that cause inflammation, swelling, pain and fever.The predominant product of cyclooxygenase in platelets is thromboxane A2 that is necessary for platelet aggregation.

The antithrombotic action of aspirin (acetylsalicylic acid) is due to inhibition of platelet function by acetylation of the platelet cyclooxygenase (COX) at the functionally important amino acid serine at position 529. This prevents the access of the substrate (arachidonic acid) to the catalytic site of the enzyme at tyrosine and results in an irreversible inhibition of platelet-dependent thromboxane formation. Aspirin is an approximately 150- to 200-fold more potent inhibitor of the (constitutive) isoform of the platelet enzyme (COX-1) than the (inducible) isoform (COX-2) which is expressed by cytokines, inflammatory stimuli, and some growth factors [1].

2. Ischemic stroke prevention: Aspirin reduces the incidence of recurrent myocardial infarction and stroke. It also reduces significantly the incidence of a first nonfatal myocardial infarction. Aspirin works by inhibiting platelet function (platelets are the tiny blood cells that trigger blood clotting). Thromboxane B2 (TxB2) is an indicator of platelet activation that drops as platelet function is inhibited by aspirin during heart attack and stroke [2].

3. Aspirin reduces risk of pre-eclampsia: Pre-eclampsia and other hypertensive disorders of pregnancy are leading causes of maternal and infant illness and death globally. Such disorders are estimated to cause 76,000 maternal and 500,000 infant deaths each year, according to the Pre-eclampsia Foundation. Pre-eclampsia is characterized by a sudden increase in blood pressure and protein in the urine, which can occur after the 20th week of pregnancy and often results in pre-term birth [3]. It can lead to eclampsia, renal or liver failure, cardiac, pulmonary and other maternal health complications. Low-dose aspirin (81 mg) initiated in early pregnancy is an efficient method of reducing the incidence of preeclampsia and IUGR (intrauterine growth restriction). Preeclampsia is associated with an imbalance of increased thromboxane and decreased prostacyclin and an abnormal increase of lipid peroxides (lipid peroxides are toxic compounds that damage cells and inhibit prostacyclin synthesis) [4]. The protective effect of aspirin is mediated by a decrease in thromboxane A2 production without a reduction in prostacyclin production, which thus prevents the vasoconstriction and coagulation problems that are characteristic of preeclampsia.

Though aspirin has several health benefits, combining this drug with other anticoagulant drug (ibuprofen or heparin) may result into internal/gastrointestinal bleeding that could be life threatening.  

References:

1. https://www.ncbi.nlm.nih.gov/pubmed/9263351
2. http://onlinelibrary.wiley.com/doi/10.1111/j.1538-7836.2007.02387.x/full
3. https://www.sciencedaily.com/releases/2017/06/170628095923.htm
4. https://www.ncbi.nlm.nih.gov/pubmed/1415427