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# Ticagrelor
## Overview
Ticagrelor is a reversible, non-thienopyridine P2Y12 platelet inhibitor that directly binds to the P2Y12 receptor. Unlike clopidogrel, it does not require metabolic activation.
## Primary Indications
* Acute coronary syndrome (ACS): Reduction of thrombotic cardiovascular events (unstable angina, NSTEMI, STEMI).
* History of myocardial infarction (MI): Reduction of risk of cardiovascular death, MI, and stroke in patients with a history of MI (off-label or specific high-risk criteria).
* Coronary artery disease (CAD): Reduction in the risk of stroke in patients with high-risk CAD.
## Adult Dosing
* **Loading Dose:** 180 mg orally single dose.
* **Maintenance Dose:** 90 mg orally twice daily.
* **Post-Initial Year (if indicated for high-risk CAD):** May reduce to 60 mg twice daily.
* **Aspirin co-administration:** Maintenance dose of aspirin should not exceed 100 mg daily. High-dose aspirin (>100 mg) reduces the efficacy of ticagrelor.
## Pediatric Dosing
Safety and efficacy have not been established in pediatric patients. Use is generally avoided unless directed by specialized pediatric cardiology protocols.
## Dose Adjustments
* **Renal Impairment:** No dosage adjustment indicated; use with caution in severe renal impairment.
* **Hepatic Impairment:** Avoid in severe hepatic impairment. No dose adjustment needed for mild impairment.
* **Surgery:** Discontinue at least 5 days prior to elective surgery to allow platelet function to recover.
## Contraindications
* Active pathological bleeding (e.g., peptic ulcer, intracranial hemorrhage).
* History of intracranial hemorrhage.
* Severe hepatic impairment.
* Known hypersensitivity to ticagrelor.
## Adverse Effects
* **Bleeding:** Major and minor bleeding (epistaxis, hematomas, GI bleeding).
* **Dyspnea:** Reported in 10–14% of patients; generally mild to moderate, usually does not necessitate discontinuation.
* **Bradyarrhythmias:** Ventricular pauses (usually within the first week of treatment).
* **Hyperuricemia:** May increase serum uric acid levels.
## Key Drug Interactions
* **CYP3A4 Inhibitors (e.g., ketoconazole, clarithromycin, ritonavir):** Avoid concurrent use; significantly increases ticagrelor exposure.
* **CYP3A4 Inducers (e.g., rifampin, phenytoin):** Avoid concurrent use; significantly decreases ticagrelor efficacy.
* **Simvastatin/Lovastatin:** Limit dose to 40 mg daily; ticagrelor increases systemic exposure to these statins.
* **Digoxin:** Monitor levels closely upon initiation of ticagrelor.
## Monitoring
* **Signs/Symptoms of Bleeding:** Baseline and ongoing monitoring for occult or overt blood loss.
* **Adherence:** High risk of thrombotic events if doses are missed; emphasize strict twice-daily adherence.
* **Dyspnea:** Observe for onset of shortness of breath.
## Clinical Pearls
* **Reversibility:** Unlike clopidogrel and prasugrel, ticagrelor is a reversible P2Y12 inhibitor; platelet function recovers faster (approx. 3–5 days after discontinuation).
* **Aspirin Ceiling:** Explicitly instruct patients to avoid exceeding 100 mg of aspirin daily.
* **Administration:** May be crushed and mixed with water if the patient has difficulty swallowing or has a nasogastric tube.
* **Switching:** If switching from clopidogrel, administer the ticagrelor 180 mg loading dose at the time of the next scheduled clopidogrel dose.
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**Educational Disclaimer:** This information is for educational purposes only. Clinical practice guidelines vary by institution and region. Always consult the most current official prescribing information (FDA/EMA labels) and verify all doses with institutional protocols before prescribing or administering medication.
