Aspirin and Clopidogrel

What is Aspirin?

Aspirin is an analgesic, non-steroidal anti-inflammatory drug which is used widely for the treatment of fever, inflammation and mild to moderate pain.

Aspirin also plays a key role in the treatment of inflammatory diseases such as rheumatoid arthritis (a progressive autoimmune disease primarily causes inflammation in joints), osteoarthritis (a disease of joint caused by breakdown of joint cartilage) and to reduce the risk of heart attack and deaths caused by heart attack.

Aspirin is usually recommended for the patients of ischemic stroke (blockage of blood flow to brain due to blood clot) or mini stroke (blockage of blood flow to brain for short time).

This drug is also used to treat the angina (sensation of chest pain occur when heart muscle does not get enough oxygen). The drug is available under generic name Acetylsalicylic acid (ASA) and brand name Aspirin.

The active component of the drug aspirin is salicylic acid, which was initially isolated by Edward Stone from the bark of willow tree in 1763. The drug was first chemically synthesized by Felix Hoffmann at Bayer in 1897.

Aspirin is available as acetylsalicylic acid, which is a synthetic pharmaceutical aromatic homomonocyclic compound with a molecular formula C9H8O4. The drug Aspirin is chemically known as 2-(acetyloxy) benzoic acid.

It is available in the form of regular strength tablets and caplets, extra strength tablet, delayed-release tablet and quick chewable tablets for oral administration with food or without food.
Aspirin tablets

What is Clopidogrel?

Clopidogrel is an oral, thienopyridine-class drug that is used to inhibit blood clots formation. The drug is available under generic name Clopidogrel and brand name Plavix worldwide.

Clopidogrel is an antiplatelet agent that is primarily used to prevent or inhibit the formation of blood clots in a variety of medical conditions including coronary artery disease, peripheral vascular disease, and cerebrovascular disease.

The drug is recommended to reduce the risk of stroke and myocardial infarction (heart attack) in people who have already had a history of myocardial infarction, other forms of acute coronary syndrome, unstable angina, stroke, and peripheral artery disease.

Clopidogrel is also used in combination with acetylsalicylic acid (ASA, aspirin), to prevent thrombosis (blood clotting) following placement of a coronary stent (a tube shaped appliance that is used to keep the arteries open in the treatment of coronary heart disease).

Clopidogrel is also used in combination with acetylsalicylic acid as an alternative antiplatelet drug in people with a history of gastric ulceration or when aspirin cannot be used.

Clopidogrel or a related drug is also recommended for patients with myocardial infarction with ST-elevation, percutaneous coronary intervention (PCI), fibrinolytic therapy, non-ST elevation myocardial infarction or unstable angina and stable ischemic heart disease.

Clopidogrel is available as a bisulfate salt and is a synthetic pharmaceutical organic compound with molecular formula C16H16ClNO2S.

The drug is chemically known as methyl (2S)-2-(2-chlorophenyl)-2-{4H,5H,6H,7H-thieno[3,2-c]pyridin-5-yl}acetate. The medication is supplied as either pink, round, biconvex, or pink, oblong film-coated tablets for oral administration by mouth.
Clopidogrel tablets.

How Aspirin and Clopidogrel work?

Aspirin is a non-steroidal anti-inflammatory drug that inhibits cyclooxygenase (COX) enzyme therefore known as COX inhibitor agent.

The action of both acetyl and salicylate component of the acetylsalicylic acid (ASA or Aspirin) and its active metabolite salicylate are liable for the anti-inflammatory and analgesic properties through inhibition of cyclooxygenases.

ASA inhibits the COX (both COX-1 and COX-2) activity by binding to it irreversibly.  Inhibition of COX results in reduced formation of precursors of prostaglandins and thromboxane from arachidonic acid.

Antipyretic effect of ASA results from the intervention in production of Prostaglandin E1 which is a potent pyretic agent. ASA also inhibits the aggregation of platelets. This inhibitory effect of ASA is resulted from the intervention in production of Thromboxane A2 which is accountable for the platelets aggregation.

Clopidogrel is an antiplatelet agent that prevents the formation of blood clots. When metabolized by the body, the active metabolite of the drug binds irreversibly to the P2Y12 subtype of adenosine diphosphate (ADP) receptor on the platelets.

The occupancy of the platelet receptor (involved in the aggregation of platelets and cross-linking by fibrin protein) by the drug impairs the binding of ADP to the receptor and thus, the activation of the glycoprotein GPIIb/IIIa complex.

GPIIb/IIIa complex is the major receptor for fibrinogen whose impaired activation prevents binding of fibrinogen to platelets and inhibits platelets from sticking to each other. Clopidogrel interference with the platelet functions and prevents blot clots formation inside the blood vessels.
Clopidogrel tablets.

Can both Aspirin and Clopidogrel be taken together in combination?

Yes, both the drugs can be taken together in combination. Clinical studies indicate the safety and efficacy of using the combination of the drugs for a variety of purposes.

The fixed dose combination of Aspirin and Clopidogrel is available commercially under brand name Clopivas-AP 75/150 (containing 75 mg or 150 mg each of Clopidogrel and Aspirin).

The other brand names of Clopidogrel-Aspirin combination are Antiban-ASP, Asicom PLUS, Antiplar Plus , Asogrel-A etc. most suitable indications for the use of combined Clopidogrel and Aspirin therapy includes the treatment of acute coronary syndromes and the prevention of coronary events after placement of a stent.

Current clinical data supports short-term use of combination therapy (approximately 1 to 2 weeks) for patients with an ST-segment elevation myocardial infarction and who do not receive stent placement in the course of treatment.

However, long term combination therapy is more beneficial in case of patients with unstable angina or non-ST-segment elevation myocardial infarction.

Dual combination therapy (for an average duration of 9 months) also offers advantage in reducing the incidence of cardiovascular death, myocardial infarction (MI), and stroke at 12 months over monotherapy involving Aspirin alone.

Clopidogrel in combination with Aspirin is also prescribed for treatment of non-ST segment elevation acute coronary syndrome in patients at moderate to high risk of MI or death.

Clopidogrel in combination with Aspirin is advised for 12 months after the most recent acute episode of non-ST elevation acute coronary syndrome. This is followed by standard care, including treatment with low-dose aspirin.

Dual combination involving Clopidogrel and Aspirin is also recommended before a percutaneous coronary intervention (PCI) so as to reduce the risk of major ischaemic events (cardiovascular death, MI or urgent target vessel revascularisation within 1 month of PCI.

Combination therapy for a minimum of 28 days is also highly useful in the patient receiving coronary stents to decrease the incidence of acute and subacute stent thrombosis.

Clinical data indicates the effectiveness and safety of Clopidogrel use in combination with Aspirin for different durations depending on the type of stent deployed e.g., duration of 4 weeks in case where a bare metal stent has been deployed and 12 months where a drug-eluting stent has been deployed. Shorter or longer use of combination therapy is usually recommended as required for specific individual circumstances.

Clopivas-AP 75 tablets copy

Safety and precautions while taking Aspirin: Clopidogrel combination

  • In patients with recent TIA (transient ischemic attack) or stroke and highly prone for recurrent ischemic events, the dual therapy of Aspirin and Clopidogrel is not very effective than that of Clopidogrel alone, but the combination increases major bleeding.
  • Clopidogrel extends the duration of the bleeding time and therefore should be used with caution in patients at risk of increased bleeding from trauma, surgery, or other pathological conditions especially gastrointestinal and intraocular.
  • The Aspirin and Clopidogrel may interact with other drugs. Therefore, care should be taken when you are taking any prescription or non-prescription medicines and herbal or vitamin supplements. It is advisable that you do not start, stop or change or take any medicine unless you have discussed with your doctor or professional consult.
  • Do not use the medicine if you are hypersensitive or allergic (e.g., anaphylaxis) to Clopidogrel, any of its constituents or any other antiplatelet drug and Aspirin or any of its ingredients.
  • Aspirin and Clopidogrel both are generally not recommended to be taken in case of pregnancy and breastfeeding.
  • Administration of the drugs (Aspirin and Clopidogrel) is usually not recommended in patients with bleeding disorders or hemorrhagic disorders.
  • Do not share this medication with other persons having the similar kind of problems. Consult your doctor for more details.

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