Skip to main content

Lecture Notes on Antiplatelet agents

Overview of the Topics
Antiplatelet Drugs (Click Here)

Antiplatelet drugs

- Platelet aggregation occurs in response to vascular injury
- The aggregation of platelets  in the coronary artery can lead to the development of atherosclerotic plaque
- It may precipitate coronary vasospasm, myocardial infarction, and stroke

Clinical Indication
- Prophylaxis of arterial thrombosis
- Therapeutic management of myocardial infarction and stroke
- Should be infused within 2 hours of myocardial infarction or stroke for significant benefit

Clinically Important Antiplatelet Agents
- Thromboxane A2 pathway, ADP pathway & GPIIb/IIIa receptors are the therapeutic targets to prevent platelet activation and aggregation. The drugs include
- Aspirin
- Clopidogrel
- Abciximab

Aspirin

- Aspirin inhibits platelet aggregation and prolongs bleeding time 
- Aspirin irreversibly inhibits an enzyme cycloxygenase (COX-1) in platelets and prevents the formation of thromboxane A2
- In endothelial cells, aspirin inhibits the synthesis of prostacyclin (PGI2)
- The selective inhibition of thromboxane A2  inhibits platelet activation (See figure above)
- Aspirin shows drug interaction with ibuprofen, ibuprofen lowers the effect of aspirin by decreasing the availability of COX for acetylation.

Clopidogrel

-Clopidogrel and structurally related drugs irreversibly inhibit specific purinergic receptors and interfere with ADP and receptor binding
- This results in decreased ADP induced expression of platelet membrane GPIIb/IIIba and fibrinogen binding to platelets
- Often used for prevention of thrombotic stroke in patients that cannot tolerate aspirin 

Abciximab
- Chimeric monoclonal antibody Abciximab binds to the GPIIb/IIIa complex  
- inhibits the interaction of fibrinogen and von Willebrand's factor with the integrin receptor
- decreases the platelet aggregation

For more information on Antiplatelet medications visit: https://www.ncbi.nlm.nih.gov/books/NBK537062/, https://www.ncbi.nlm.nih.gov/books/NBK470539/


Labels:

Comments

Post a Comment

Popular posts from this blog

Multiple Choice Questions (MCQs) on Diabetes Mellitus: Pathogenesis, Diagnosis and Treatment

                                        MCQs on Diabetes mellitus 1) Diabetes mellitus is a disorder characterized by hyperglycemia.  Which of the following is not the common characteristic features of type 2 diabetes mellitus ? a) Impaired insulin secretion b) Increased Insulin resistance  c) Diabetic ketoacidosis d) Excessive hepatic glucose production 2) Which of the following are the characteristic features of type 1 diabetes mellitus? a) Type 1 diabetes is caused by an absolute deficiency of insulin. b) Type 1 diabetes is associated with the autoimmune destruction of beta cells.  c) Patients with  uncontrolled type 1 diabetes present with diabetic ketoacidosis d) All of the above   3) Which of the following serum measurements are not used for the diagnosis of diabetes mellitus? a) Fasting blood glucose d) Postprandial blood glucose  c) Insulin ...
6 comments
Read More

MCQs on Superficial and Cutaneous Mycoses-Dermatophytes: Medical Mycology

  Multiple Choice Questions on Superficial and Cutaneous Fungal Infections 1. All of the following are examples of common superficial mycoses, EXCEPT ? a) Aspergillosis b) Candidiasis c) Tinea versicolor d) Tinea nigra 2. Which of the following statement regarding Tinea nigra infection is NOT correct? a) Most prevalent in the tropical and subtropical region b) Symptoms include pigmented macules on palm and soles c) Trycophyton spp is the causative fungi d) Common specimen is skin scrapings 3. The fungi Trichosporon commonly causes superficial infection of hair also called white piedra. Which of the following species of Trichosporon causes scalp hair white piedra ? a) T. ovoides b) T. inkin c) T. asahii d) None of the above 4. All of the following are the characteristics of cutaneous mycoses, EXCEPT ? a) The infection of hair, skin, and nails b) The common cause of ringworm in humans only c) Candida spp is associated with the infection d) The keratinize...
3 comments
Read More

MCQs on Human Immunodeficiency Virus (HIV/ AIDS) with answers: Medical Microbiology

Multiple Choice Questions on Human Immunodeficiency Virus (HIV/AIDS) with answers 1) Which virus is associated with acquired immune deficiency syndrome (AIDS) pandemic? A) HIV-2 B) HTLV-1 C) HIV-1 D) HIV-3 2) Which of the following is an important molecule present in the outer membrane of HIV that helps the virus to enter and infect host cells? a) Polysaccharides b) Glycoproteins c) Proteins d) Lipopolysaccharides 3) Select all the incorrect options given below for the common route of transmission of HIV from one person to another? a) Unprotected sexual contact with an infected person b) From infected mother to the fetus c) From the mosquito bite  d) Exposure to contaminated blood and blood products e) Using and sharing the same swimming pool  4) HIV belongs to which of the following genus member of the virus? a) Orthomyxovirus b) Retrovirus c) Parvovirus d) Reovirus 5) All of the following statements regarding HIV infection in human is true, ...
3 comments
Read More