Clopidogrel Use, Side Effect , Mechanism of Action and Adverse Reaction

Clopidogrel Use

Clopidogrel is use for preventing cloting of at the time of internal injury. Platelet are very
small in structure but when it clump each other at time of clotting. This medicine is also
 for the treatment of disease like heart stroke, Heart attacks and helps to prevent the
disease lood circulation.
This medicine is given with aspirin to prevent the disease of new chest pain.
Clopidogrel tablets
Clopidogrel tablets

Clopidogrel side effects

Like other medicine Clopidogrel is show some side effects. Some common side effects

  • Bleeding occurs in the stomach
  • Bruising
  • Hematoma
  • Bruising under the skin
  • Nose bleed
  • Blood in the urine
  • Bleeding in the eye
  • Inside the head bleeding
Contact your doctor or pharmacist to prevent this type of side effects

Some other side effects are

  • Diarrhea
  • abdominal pain
  • indigestion
  • heartburn

Clopidogrel Mechanism of action

Clopidogrel poticularly inhibits the binding of adenosine diphosphate (ADP) to the platelet receptor and subsequent ADP-mediated ADP activation of the GPIIb / IIIa complex, thereby inhibiting platelet aggregation. In order to exert its anti-aggregation action, clopidogrel requires biotransformation. This medicine also inhibits platelet aggregation induced by other antagonists, blocking the enhancement of platelet activation by ADP release. Clopidogrel acts by irreversible modulation of the platelet receptor for ADP. Consequently, the platelet functionality exposed to clopidogrel is affected for the rest of its life, and restoring a normal platelet function corresponds to the duration of the platelet turnover.
Clopidogrel 3D structure

Repeated dosing of 75 mg per day resulted in a significant inhibition of ADP induced platelet
aggregation starting on the first day of treatment; this inhibition then progressively increases
and reaches the equilibrium state between the 3rd and the 7th day. At steady state, the daily
dose of 75 mg allowed for an average inhibition level of between 40% and 60%. Platelet
aggregation aclond bleeding time gradually returned to baseline, generally within 5 days after discontinuation.

Pharmacokinetic Clopidogrel

Clopidogrel is rapidly absorbed after repeated oral dosing of 75 mg per day. However, theplasma concentrations of the unmodified molecule are very low and below the detectablelimit (0.00025 mg / l), starting at 2 hours after administration. Based on data on the urinaryelimination of clopidogrel metabolites, its absorption is at least 50%.Clopidogrel is extensively metabolised in the liver, and the main metabolite lackingpharmacological activity is the carboxylic acid derivative, which accounts for approximately85% of the circulating plasma concentration. The maximum plasma concentration of thismetabolite is reached approximately 1 hour after administration.Clopidogrel is a pro-drug. The active metabolite, a thiol derivative, is formed by oxidation ofclopidogrel to 2-oxo-clopidogrel, followed by hydrolysis. The oxidative step is primarilyregulated by cytochrome P450 isoenzymes 2B6 and 3A4 and, to a lesser extent, byisoenzymes 1A1, 1A2 and 2C19.In vitro, clopidogrel and its major circulating metabolite are reversibly bound to human
plasma proteins (98% and 94%, respectively).For 120 hours after oral administration, 50% of the dose of clopidogrel is eliminated in theurine and about 46% in the faeces. The elimination half-life for the main circulating metaboliteis 8 hours, both after a single dose and after repeated administration.Following repeated administration of clopidogrel at a dose of 75 mg / day, plasmaconcentrations of the circulating active metabolite were lower in patients with severe renalimpairment (creatinine clearance 5-15 ml / min) compared to those with moderate renalimpairment (creatinine clearance from 30 to 60 ml / min) and with concentrations seen inother investigations in healthy individuals.

Therapeutic indications of Clopidogrel

Clopidogrel is indicated in adults for the prevention of atherothrombotic complications
• patients with myocardial infarction (a few days earlier but more than 35 days), ischemic
stroke (older than 7 days but more than 6 months) or proven lower limb arterial disease;
• patients with acute coronary syndrome:

- acute coronary syndrome with no ST segment elevation (unstable angina or non-Q
myocardial infarction), including stent implants after percutaneous coronary intervention in
combination with acetylsalicylic acid (AAS);
- acute myocardial infarction with ST segment elevation, in combination with AAS, in
medically treated patients eligible for thrombolytic therapy.

How to take Clopidogrel ?

Adults and elderly
Clopidogrel should be administered at a dose of 75 mg once a day, regardless of food intake.
In patients with acute coronary syndrome
Fructuation ST segment elevation (unstable angina pectoris or non-Q myocardial infarction):
clopidogrel treatment should be initiated with a single 300 mg loading dose and then
continued at 75 mg once daily (in association with acetylsalicylic acid (AAS) 75 mg - 325 mg
per day). Because higher doses of AAS have been associated with an increased risk of
bleeding, it is recommended that the AAS dose does not exceed 100 mg. The optimal
duration of treatment has not been accurately established. Clinical trial data support its use
up to 12 months, and the maximum benefit was seen at 3 months.  
- ST segment elevation acute myocardial infarction: clopidogrel should be administered at a
dose of 75 mg / day, initiating a 300 mg dose in combination with AAS and with or without
thrombolytics. In patients over 75 years of age, clopidogrel should be initiated without the
loading dose. Associated treatment should be started as soon as possible after the onset of
symptoms and continued for at least 4 weeks. The benefit of clopidogrel with AAS for more
than 4 weeks has not been studied in this context.
Adverse Reaction
Reactions are classified by system organ class and frequency according to frequency:
common (≥1 / 100 and <1/10); occasional (≥1 / 1000 and <1/100); rare (≥1 / 10,000 and
<1 / 1,000); very rare (<1 / 10,000).
Within each frequency grouping, undesirable effects are presented in order of decreasing
Haematological and lymphatic system disorders
Occasional: thrombocytopenia, leukopenia, eosinophilia.
Rare: neutropenia, including severe
Very rare: thrombotic purpura, thrombocytopenic (PTT), aplastic anemia, pancytopenia,
agranulocytosis, severe thrombocytopenia, anemia, granulocytopenia.
Immune system disorders
Very rare: serum sickness, anaphylactoid reactions.
Psychiatric disorders
Very rare: hallucinations, confusion.
Nervous system disorders
Occasional: Intracranial haemorrhage (few cases of fatal outcome have been reported),
headache, paraesthesia, dizziness.
Very rare: taste disturbances. Occasional
eye disorders
: Ophthalmic haemorrhage (conjunctival, intraocular, retinal).
Ear and labyrinth
disorders Rare: vertigo.
Vascular disorders
Common: hematoma.

Clopidogrel Use, Side Effect , Mechanism of Action and Adverse Reaction Clopidogrel Use, Side Effect , Mechanism of Action and Adverse Reaction Reviewed by aboutmedicine on 17:19 Rating: 5

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