A commonly used antiplatelet drug: Clopidogrel👴👴👴

Clopidogrel is an antiplatelet drug that is indicated for preventing thrombotic events in patients with ischemic stroke, myocardial infarction and peripheral arterial disease. However, although antiplatelet drugs can prevent thrombosis, they can also cause serious adverse reactions such as bleeding. Therefore, every patient taking clopidogrel should know how to take it correctly.

1. Is Clopidogrel taken before or after a meal?

Recommended dosage: 75mg each time, once a day. 

Recommended usage: Oral, with or without food.

The medication is taken at a fixed time, either before or after a meal. If the patient can tolerate it, the medication time should not be changed at will.

2. What should you do if you miss taking a dose?

After oral administration of clopidogrel 75 mg, the elimination half-life of clopidogrel is 6 hours and the elimination half-life of active metabolites is about 30 minutes. If a missed dose is found within 12 hours of the regular medication time, the patient should take a standard dose immediately and take the next dose according to the regular medication time. If a missed dose is found 12 hours after the regular medication time, the patient should take the standard dose at the next regular medication time without doubling the dose.

3. Pharmacokinetic characteristics.

Clopidogrel is a prodrug. After oral absorption of clopidogrel through the intestine, most (about 85%) are hydrolyzed by esterase into inactive carboxylic acid derivatives, and only 15% is converted into thiol metabolites with antiplatelet activity by CYP2C19. Inactive carboxylic acid derivatives are strong inhibitors of CYP2C8. CYP2C19 is a key enzyme for the activation of clopidogrel. Due to the genetic diversity of CYP2C19, weak metabolizers of CYP2C19 will have a reduced response to clopidogrel. Clinically, the patient's genotype can be tested. If it is a weak metabolizer, it is recommended to switch to other antiplatelet drugs.

4. Avoid combination with repaglinide.

Repaglinide is a commonly used hypoglycemic agent in clinical practice. It reduces postprandial blood sugar by stimulating the early secretion of insulin, which can cause fatal hypoglycemia. Repaglinide is mainly metabolized by CYP2C8 and CYP3A4. Because the inactive carboxylic acid derivatives of clopidogrel can significantly inhibit CYP2C8, the combination of clopidogrel and repaglinide can inhibit the metabolism of repaglinide in the body. It will increase the blood concentration of repaglinide by 3.9 to 5.1 times and increase the risk of hypoglycemia. Therefore, clopidogrel should be avoided in combination with repaglinide.

5. Can clopidogrel be used in combination with proton pump inhibitors?

Clopidogrel can increase the risk of gastrointestinal bleeding. Combined use with proton pump inhibitors can reduce the bleeding risk of clopidogrel. Clopidogrel is a prodrug. It can become an active substance that can inhibit platelet aggregation after being transformed by CYP2C19 in the body. Therefore, CYP2C19 inhibitors can reduce the antiplatelet effect of clopidogrel. Omeprazole and esomeprazole can inhibit CYP2C19, leading to the inhibition of clopidogrel's conversion into active metabolites, reducing its efficacy. Therefore, clopidogrel should not be combined with omeprazole and esomeprazole. According to its drug instructions, clopidogrel can be combined with pantoprazole. However, the combination of clopidogrel and PPI is not recommended clinically. If you must use them together, you should avoid the use of omeprazole and esomeprazole.