Antiplatelet agents – P2Y12 receptor inhibitors
ATC code: B01AC04 (Clopidogrel)
A prodrug. Bioactivated in the liver by two sequential oxidations involving CYP2C19, CYP3A4, CYP2B6 and CYP1A2 into a thiol active metabolite, which irreversibly inhibits the platelet P2Y12 ADP receptor – blocking ADP-dependent aggregation for 7–10 days. In carriers of the defective CYP2C19*2/*3 alleles, activation is reduced – with a clinically meaningful loss of antiplatelet effect ( black box). Used as monotherapy or as part of dual antiplatelet therapy after ACS or stenting.
First line
Clopidogrel plus aspirin (DAPT) is the standard after acute coronary syndrome and percutaneous coronary intervention. The CURE trial showed a 20 % reduction in the composite of vascular death, MI, and stroke. DAPT duration is 6–12 months depending on stent type and bleeding risk. Clopidogrel monotherapy is an alternative when aspirin is not tolerated.
After ACS, given as part of dual antiplatelet therapy (DAPT) with aspirin for 6–12 months.
First line
Clopidogrel is one of the antiplatelet options for secondary prevention of ischemic stroke. The CAPRIE trial demonstrated a small but statistically significant advantage of clopidogrel over aspirin in preventing ischemic events. Dose is 75 mg once daily long-term.
First line
In peripheral artery disease, clopidogrel is the preferred antiplatelet agent. Subgroup analyses from CAPRIE showed a particularly pronounced advantage over aspirin in this population. Dose is 75 mg daily.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Clopidogrel is taken by healthy adults for blood thinning instead of or alongside aspirin in anti-aging protocols. 2024 and 2023 confine clopidogrel to secondary prevention in coronary artery disease, peripheral arterial disease, post-stenting and acute coronary syndrome. Healthy-adult hard-endpoint data are absent. Use creates increased bleeding risk without equivalent thromboembolic reduction.
15 pairs found. Sorted from critical to minor.
Mechanism
Apixaban directly inhibits factor Xa; clopidogrel blocks the platelet P2Y12 receptor. The two antithrombotic mechanisms add up.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage. Risk rises in patients over 65 and with prior peptic ulcer disease.
Management
Dual therapy is used after acute coronary syndrome or stenting in atrial fibrillation, generally for no more than 1–6 months. Apixaban dose is selected according to age, weight, and renal function. PPI cover with pantoprazole is mandatory.
Sources
Mechanism
Esomeprazole inhibits CYP2C19, the key enzyme that converts clopidogrel to its active metabolite. Active clopidogrel levels fall by about 35%, weakening antiplatelet effect.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. The combination raises recurrent myocardial infarction and stent thrombosis risk in patients with prior stenting or acute coronary syndrome.
Management
Replace esomeprazole with pantoprazole (minimal CYP2C19 impact). Among other PPIs, rabeprazole is an alternative. If a PPI is not required, switch to famotidine (H2-blocker) or stop acid suppression.
Mechanism
Fluconazole inhibits CYP2C19, the key enzyme converting clopidogrel into its active metabolite. Active levels fall by 25–50% and the antiplatelet effect weakens.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. Risk of recurrent coronary events and stent thrombosis rises.
Management
For a short fluconazole course, the effect is clinically minor. For prolonged systemic therapy (>14 days), an alternative antiplatelet is ticagrelor (not CYP2C19-dependent). Alternative antifungal: echinocandins for systemic mycoses.
Mechanism
Fluoxetine inhibits CYP2C19, the enzyme converting clopidogrel into its active metabolite. Active levels fall and antiplatelet effect weakens. Fluoxetine also depletes the platelet serotonin pool, impairing primary haemostasis.
Symptoms
Dual risk: weakened antiplatelet effect (raising thrombosis risk) alongside increased upper GI bleeding risk.
Management
Alternative antidepressants: sertraline or escitalopram (weaker CYP2C19 inhibitors), or mirtazapine/agomelatine (minimal platelet effect). Alternative antiplatelet: ticagrelor (not CYP2C19-dependent). PPI cover with pantoprazole is mandatory.
Mechanism
Clopidogrel is a prodrug, activated by CYP2C19. Fluvoxamine is a potent CYP2C19 inhibitor. The active clopidogrel metabolite is not formed and antiplatelet effect is lost.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. The combination raises recurrent myocardial infarction, stent thrombosis, and stroke risks.
Management
The combination is not prescribed. Alternative antidepressants without CYP2C19 effect: sertraline or escitalopram (moderate but weaker effect), or mirtazapine/agomelatine (no effect). Alternative antiplatelet: ticagrelor (not CYP2C19-dependent).
Mechanism
Clopidogrel is a prodrug. It must be converted in the liver via CYP2C19 into its active antiplatelet metabolite. Omeprazole strongly inhibits CYP2C19: active metabolite levels drop by 45% and platelet inhibition weakens. The issued a dedicated warning about this pair in 2009.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. The combination raises the risk of recurrent myocardial infarction, stent thrombosis, and stroke in patients with prior stenting or acute coronary syndrome.
Management
Replace omeprazole with pantoprazole, which has minimal effect on CYP2C19. Among other proton pump inhibitors, rabeprazole is an alternative. If a PPI is not required, switch to famotidine (an H2-blocker that does not affect CYP2C19) or stop acid suppression altogether.
Mechanism
Ritonavir blocks CYP3A4 and CYP2C19, through which clopidogrel becomes its active metabolite. The active metabolite is not formed – antiplatelet effect is lost. Ritonavir also induces glucuronidation, further reducing clopidogrel activity.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. In patients with a coronary stent or after acute coronary syndrome: risk of recurrent myocardial infarction, stent thrombosis, and ischaemic stroke.
Management
Avoid the combination. Alternative antiplatelet: ticagrelor (no CYP2C19 activation needed). If ticagrelor is impossible: prasugrel (requires activation but via a different route) with caution.
Mechanism
Clopidogrel blocks the platelet P2Y12 receptor; rivaroxaban directly inhibits factor Xa. The two antithrombotic mechanisms add up, roughly doubling major bleeding risk.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage. Risk rises in patients over 65 and with prior peptic ulcer disease.
Management
Dual therapy is used after acute coronary syndrome or stenting in atrial fibrillation, generally for no more than 1–6 months. Rivaroxaban dose is adjusted to age and renal function. PPI cover with pantoprazole is mandatory.
Mechanism
Warfarin blocks vitamin K-dependent clotting factor synthesis; clopidogrel inhibits platelet aggregation via the P2Y12 receptor. The two antithrombotic mechanisms add up.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage. Risk rises in patients over 65 and with prior peptic ulcer disease.
Management
Combine only for clear indications. Limit dual therapy to 1–6 months depending on risk. Keep INR at the lower end of the target range (2.0–2.5) and provide PPI cover with pantoprazole.
Mechanism
Warfarin blocks vitamin K-dependent clotting factor synthesis; clopidogrel inhibits platelet aggregation via the P2Y12 receptor. The two antithrombotic mechanisms add up.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage. Risk rises in patients over 65 and with prior peptic ulcer disease.
Management
Combine only for clear indications (e.g., atrial fibrillation plus coronary stent). Limit dual therapy to 1–6 months depending on risk. Keep INR at the lower end of the target range (2.0–2.5) and provide PPI cover with pantoprazole.
Sources
Mechanism
Additive antiplatelet effect via different targets: aspirin irreversibly blocks platelet cyclooxygenase; clopidogrel inhibits the P2Y12 receptor. The combination raises bleeding risk 1.5- to 2-fold versus monotherapy.
Symptoms
Gum bleeding, epistaxis, bruising without trauma. Severe cases: GI bleeding.
Management
The combination (dual antiplatelet therapy) is standard after acute coronary syndrome or coronary stenting. Limit duration to 1–6 months based on thrombosis and bleeding risk. Aspirin 75–100 mg/day. Mandatory PPI cover with pantoprazole.
Sources
Mechanism
Amiodarone weakly inhibits CYP2C19, the key enzyme that converts clopidogrel to its active metabolite. Effect is clinically minimal; no proven reduction in antiplatelet activity.
Symptoms
The combination usually causes no specific symptoms. Baseline clopidogrel bleeding risk and amiodarone bradycardia risk remain.
Management
No dose adjustment needed. After acute coronary syndrome, if antiplatelet activity is in doubt, consider switching to ticagrelor or prasugrel (CYP2C19-independent).
Mechanism
Ibuprofen blocks platelet aggregation via COX-1 inhibition, additively with clopidogrel. NSAIDs also injure gastric mucosa, raising GI bleeding risk 2–3-fold.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, black or tarry stools, haematuria. Higher risk in older patients, prior peptic ulcer disease, and chronic kidney disease.
Management
For analgesia on clopidogrel, use paracetamol. If NSAIDs are needed (arthritis, pain flare), choose a short course of no more than 5 days with gastroprotection (pantoprazole 20 mg/day). For osteoarthritis, alternatives include topical NSAIDs and physiotherapy. Ibuprofen can also competitively displace aspirin from the COX-1 active site, which matters for dual antiplatelet therapy.
Mechanism
Clopidogrel blocks platelet aggregation via the P2Y12 receptor; sertraline impairs primary haemostasis by inhibiting platelet serotonin reuptake. Additive bleeding risk, mainly gastrointestinal.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, black or tarry stools, haematuria. Higher risk in older patients, prior peptic ulcer disease, and chronic kidney disease.
Management
The combination is acceptable. In patients over 65 or with prior peptic ulcer disease, add gastroprotection — pantoprazole or esomeprazole 20 mg/day (avoid omeprazole — it suppresses clopidogrel activation). Antidepressant alternative without platelet effect: mirtazapine or agomelatine.
Mechanism
An early study (Lau et al., Circulation 2003) in 44 patients showed in vitro competition between atorvastatin and clopidogrel for CYP3A4. Subsequent large clinical trials (PROVE-IT, MIRACL, CHARISMA) did not confirm clinically significant attenuation of clopidogrel's antiplatelet activity.
Symptoms
The combination usually causes no specific symptoms. Each drug's individual side effects remain.
Management
Standard combination after acute coronary syndrome and in coronary artery disease. No dose adjustment needed. In patients at high risk of recurrent thrombosis with unclear antiplatelet activity, consider switching to ticagrelor or prasugrel (CYP3A4-independent).
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FDA category B. Limited human data in pregnancy. Prescribed only when benefit clearly outweighs potential risk.
No data on excretion in breast milk. Decision is individualized.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Clopidogrel is evaluated for the following indications with varying evidence strength: Established ASCVD, secondary prevention (evidence tier A), Peripheral artery disease (evidence tier A), Ischemic stroke (evidence tier A). See the full indication matrix with dosing and citations above on this page.
Common side effects of Clopidogrel (≥ 1 in 100): Bleeding (ecchymoses, epistaxis, gingival bleeding), Dyspepsia, diarrhea, Headache. See the Safety section for uncommon and serious reactions.
FDA category B. FDA category B. Limited human data in pregnancy. Prescribed only when benefit clearly outweighs potential risk.
No data on excretion in breast milk. Decision is individualized.
Clopidogrel is contraindicated in: Active bleeding (GI, intracranial); Severe hepatic impairment; Hypersensitivity to clopidogrel. Full list in the Safety section.