Do we load the ticagrelor dose when switching from clopidogrel post stent placement?

Loading Dose of Ticagrelor When Switching from Clopidogrel Post Stent Placement

Yes, a loading dose of 180 mg ticagrelor should be administered when switching from clopidogrel to ticagrelor in patients post stent placement, regardless of prior clopidogrel therapy. 1

Evidence-Based Rationale

The European Society of Cardiology (ESC) guidelines explicitly recommend that "in patients with ACS who were previously exposed to clopidogrel, switching from clopidogrel to ticagrelor is recommended early after hospital admission at a loading dose of 180 mg irrespective of timing and loading dose of clopidogrel, unless contraindications to ticagrelor exist." 1

This recommendation is supported by pharmacodynamic data showing that:

• Ticagrelor achieves greater platelet inhibition compared to clopidogrel, both in the first hours of treatment and during maintenance therapy 2
• The loading dose of ticagrelor (180 mg) achieves significant platelet inhibition within 30 minutes, with peak inhibitory effect approximately 2 hours after administration 3

Clinical Application

When switching from clopidogrel to ticagrelor:

1. Administer full loading dose: Give 180 mg ticagrelor loading dose regardless of:

   • When the last clopidogrel dose was given
   • Whether a loading dose of clopidogrel was previously administered
   • Current maintenance dose of clopidogrel

2. Discontinue clopidogrel: Stop clopidogrel immediately when ticagrelor is commenced 1

3. Follow with maintenance therapy: Continue with ticagrelor 90 mg twice daily maintenance dose after the loading dose 3

Important Considerations

Aspirin Dosing

When using ticagrelor, the recommended maintenance dose of aspirin is 81 mg daily 1, 3. Higher aspirin doses may reduce ticagrelor's effectiveness.

Contraindications

Avoid ticagrelor in patients with:

• Previous intracranial hemorrhage
• Active pathological bleeding
• Severe hepatic impairment 1, 3

Monitoring

Monitor patients for:

• Bleeding complications (more common with ticagrelor than clopidogrel)
• Dyspnea (occurs in approximately 14% of patients)
• Bradycardia and ventricular pauses 3

Special Populations

In elderly patients (≥70 years), consider the increased bleeding risk with ticagrelor compared to clopidogrel. The POPular AGE trial demonstrated that clopidogrel led to fewer bleeding events without increasing ischemic outcomes in elderly patients with NSTE-ACS 4.

Duration of Therapy

After stent placement, P2Y12 inhibitor therapy should be continued for:

• At least 12 months for ACS patients (with either BMS or DES) 1
• At least 12 months for patients receiving DES for non-ACS indications 1
• Minimum 1 month (ideally up to 12 months) for patients receiving BMS for non-ACS indications 1

In conclusion, when switching from clopidogrel to ticagrelor post stent placement, a full loading dose of 180 mg ticagrelor should be administered, followed by the standard maintenance dose of 90 mg twice daily, in accordance with current guidelines.