Can antiplatelet therapy be started in a patient who received Clexane (enoxaparin) for stroke 12 hours earlier?

Can Antiplatelet Therapy Be Started After Clexane for Acute Stroke?

Yes, antiplatelet therapy should be started after Clexane (enoxaparin) was given for stroke, but the timing depends critically on whether thrombolysis was used and the stroke subtype.

Immediate Decision Algorithm

If Patient Did NOT Receive Thrombolysis (tPA/rtPA):

Start aspirin immediately after brain imaging excludes hemorrhage and dysphagia screening is passed 1. The standard approach is:

• Loading dose: 160-325 mg aspirin immediately 1
• Continue aspirin 81-325 mg daily indefinitely 1
• Enoxaparin can be continued concurrently if indicated for DVT prophylaxis or other indications 2, 3

For high-risk TIA or minor stroke (NIHSS 0-3):

• Add clopidogrel to aspirin within 24 hours of symptom onset (ideally within 12 hours) 1
• Loading doses: 300-600 mg clopidogrel + 160 mg aspirin 1
• Continue dual therapy for only 21-30 days, then switch to monotherapy 1
• This applies to non-cardioembolic strokes with ABCD2 score >4 1

If Patient DID Receive Thrombolysis:

Delay all antiplatelet therapy for 24 hours after thrombolysis 1. This is an absolute contraindication based on the NINDS trial protocols 1.

• Perform 24-hour post-thrombolysis brain imaging to exclude intracranial hemorrhage 1
• Only after hemorrhage is excluded can aspirin be started 1

Key Safety Considerations

Bleeding Risk with Combined Therapy:

The combination of enoxaparin and antiplatelets does increase bleeding risk, but this must be weighed against thrombotic risk 1:

• Aspirin alone with enoxaparin: Modest increase in bleeding complications, but acceptable risk-benefit profile for most patients 1
• Dual antiplatelet therapy (aspirin + clopidogrel) with enoxaparin: Higher bleeding risk (0.9% major hemorrhage vs 0.4% with monotherapy), but prevents 15 ischemic strokes per 1000 patients treated 1
• The bleeding risk is "sufficiently high to require convincing evidence of efficacy" but is lower than with thrombolytic agents 1

Hemorrhagic Transformation Risk:

Early anticoagulation with enoxaparin increases symptomatic intracranial hemorrhage risk, especially in severe strokes 1. However:

• Research shows enoxaparin is as safe as unfractionated heparin for stroke patients 2, 3
• Fewer hemorrhagic transformations occurred with enoxaparin (13.2%) compared to UFH (18.9%) in one trial 3

Specific Clinical Scenarios

Large-Artery Atherosclerosis:

• This subgroup may benefit most from early anticoagulation 1
• Consider continuing enoxaparin while adding antiplatelet therapy 1

Cardioembolic Stroke:

• Enoxaparin did not reduce neurological worsening or early recurrent stroke in cardioembolic events 1
• Transition to appropriate long-term anticoagulation (typically warfarin or DOAC) rather than antiplatelets 1

Patients Already on Antiplatelets Before Stroke:

• If patient was on aspirin before stroke and received enoxaparin, continue aspirin immediately (no need to reload) 4, 5
• Prior antiplatelet use is associated with better functional outcomes despite slightly higher sICH risk with subsequent tPA 4
• Preceding antiplatelet therapy reduces severity of recurrent thrombotic stroke 5

Common Pitfalls to Avoid

Never switch between enoxaparin and UFH - this significantly increases bleeding risk 1, 6. If enoxaparin was started, continue it rather than switching 1.

Do not combine anticoagulants with antiplatelets in the first 24 hours post-thrombolysis - this is explicitly contraindicated based on NINDS trial protocols 1.

Do not use dual antiplatelet therapy beyond 21-30 days - the bleeding risk outweighs benefits after this period 1.

Ensure dysphagia screening before oral aspirin - use enteral tube (80 mg aspirin, 75 mg clopidogrel) or rectal suppository (325 mg aspirin) if dysphagia present 1.

Practical Implementation at 12 Hours Post-Stroke

Given your specific scenario (12 hours after stroke, already received Clexane):

1. Confirm no thrombolysis was given - if tPA was used, wait until 24-hour scan 1
2. If no thrombolysis: Start aspirin 160-325 mg immediately after confirming no hemorrhage on imaging 1
3. Assess stroke severity: If NIHSS 0-3 and non-cardioembolic, add clopidogrel 300-600 mg loading dose 1
4. Continue enoxaparin if indicated for DVT prophylaxis or other indication 2, 3
5. Monitor closely for bleeding complications, especially with dual antiplatelet therapy 1