Farmakológia a klinické využitie Brilique v podmienkach ZZS

Pharmacology and Clinical Use of Brilique (Ticagrelor) in EMS

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Introduction

Brilique (ticagrelor) is a direct-acting, reversible P2Y12 platelet receptor antagonist. In the prehospital care of STEMI or high-risk NSTEMI patients, it has replaced older clopidogrel in many protocols thanks to a faster onset and stronger inhibition of aggregation. Field administration (so-called “pretreatment”) is key to minimizing thrombotic burden before the actual procedure at the PCI center.

1. Drug Identification

Active substance: Ticagrelor.

Trade names in Slovakia: Brilique.

ATC classification: B01AC24 (Platelet aggregation inhibitors excluding heparin).

Dosage form in EMS: Tablets, 90 mg.

Pharmacological group: Antiplatelet agent, selective and reversible P2Y12 receptor antagonist.

2. Mechanism of Action (Pharmacodynamics)

Ticagrelor works differently than thienopyridines (clopidogrel, prasugrel):

Direct binding: Does not require hepatic metabolic activation (it’s not a prodrug), giving it a faster onset.

P2Y12 antagonism: Binds to a different site on the P2Y12 receptor than ADP (adenosine diphosphate), blocking the signaling pathway leading to activation of the GP IIb/IIIa complex and subsequent platelet aggregation.

Reversibility: Binding is reversible, though inhibition is nearly total in the acute phase.

Adenosine effect: Ticagrelor raises local levels of endogenous adenosine (by inhibiting the ENT-1 transporter), which can produce additional vasodilation and cardioprotection, but also side effects (dyspnea).

3. Hemodynamic Effects – IN DETAIL

SVR, preload, afterload: No direct effect on systemic hemodynamics.

Contractility: No direct effect.

Coronary microcirculation: The adenosine-mediated effect can mildly increase coronary flow, which is desirable in ACS.

Destabilization risk: The main risk is hemorrhagic instability with uncontrolled bleeding.

4. Pharmacokinetics (from a Paramedic’s Perspective)

Route of administration: Oral (PO). For patients in shock or with nausea, tablets can be crushed and given with water (speeds absorption).

Onset of action: Significant platelet inhibition occurs within 30 minutes of the loading dose.

Peak effect: 1.5 to 2.5 hours.

Duration of effect: After discontinuation, platelet function recovery takes 3 to 5 days (shorter than with clopidogrel).

5. Indications in Prehospital Practice

1. STEMI: As part of dual antiplatelet therapy (with aspirin) before primary PCI.

2. NSTEMI: In high-risk patients (after consultation with a cardiac center).

3. Acute coronary syndrome: Where an early invasive strategy is planned.

6. Dosing in EMS

Loading dose: 180 mg PO (two 90 mg tablets) at once.

Administration: Chewed or swallowed; crushed if needed.

Scope of practice: Physician (RLP). A basic-crew paramedic (RZP) administers per the ACS protocol after ECG confirmation, often after a phone consultation with the PCI center.

7. Contraindications

Absolute: Active pathological bleeding (e.g., intracranial, gastrointestinal), history of intracranial hemorrhage, severe hepatic impairment.

Relative: Concurrent oral anticoagulant therapy (warfarin, NOACs), planned urgent surgery (e.g., CABG bypass, if anatomy is known), bradycardia (risk of sinus pauses).

8. Adverse Effects

Hemorrhagic: Bleeding (epistaxis, hematuria, gastrointestinal).

Respiratory: Dyspnea (shortness of breath) — occurs in approximately 10–15% of patients, usually mild and transient (adenosine effect), but can be confusing in EMS when diagnosing pulmonary edema.

Arrhythmogenic: Ventricular pauses and bradycardia (rare).

9. Drug Interactions in EMS

Aspirin: Desired synergy in ACS treatment.

Heparin: Synergy in anticoagulant/antiplatelet action.

Opioids (morphine, fentanyl): Caution! Opioids slow gastric emptying and thereby significantly delay absorption and onset of ticagrelor. For severe pain, crushing the tablets is recommended.

10. Specifics in Emergency Medicine

Monitoring: Watch for consciousness changes (risk of CNS bleeding) and breathing.

Error #1: Giving ticagrelor when aortic dissection is suspected (precludes urgent surgical intervention).

Error #2: Omitting the dose in a STEMI patient out of fear of bleeding (increases risk of stent re-occlusion).

11. Red Flags

1. Sudden dyspnea without pulmonary crackles: Likely a drug side effect, not worsening heart failure.

2. Uncontrolled bradycardia: Ticagrelor can potentiate conduction disturbances.

3. Bleeding from multiple sites: An immediate signal for caution with further anticoagulant therapy.

12. Antidote

• No specific antidote is routinely available (a monoclonal antibody, bentracimab, exists but is not carried in EMS kits). For bleeding: platelet transfusion, though circulating ticagrelor can also block the new platelets.

13. Practical Field Scenario

Situation: A 52-year-old man with severe chest pressure and cold sweat. ECG: ST elevation in V1–V6.

Status: Stabilized, BP 140/90, HR 75.

Decision-making:

1. Aspirin 250 mg PO (chewed).

2. Brilique 180 mg PO (2 tablets).

3. Heparin 5,000 IU IV.

4. Transport to the PCI center.

Hemodynamic rationale: The patient is stable; rapid administration of Brilique ensures platelet inhibition before reaching the catheterization table, reducing the risk of a “no-reflow” phenomenon.

14. Practical Summary – 5 Key Points

1. 180 mg loading dose: Always 2 tablets to start.

2. Faster than clopidogrel: Prefer Brilique for STEMI where local protocol allows.

3. Opioids slow it down: If giving morphine, consider crushing the Brilique tablets.

4. Dyspnea is a known side effect: Don’t be alarmed if the patient complains of shortness of breath without crackles after administration.

5. Don’t drink much water: A small sip is enough, to avoid increasing the risk of vomiting.

Professional Literature for Brilique (Ticagrelor)

1. Slovak Ministry of Health guidance No. 05241/2024 on reperfusion therapy for STEMI patients.

2. SmPC (Summary of Product Characteristics) – Brilique 90 mg, EU registration no. EU/1/10/655/001-011.

3. PLATO Study Investigators: Ticagrelor versus Clopidogrel in Patients with Acute Coronary Syndromes. NEJM, 2009.

4. ESC Guidelines 2023 for the management of acute coronary syndromes.

5. Katzung, B. G.: Basic and Clinical Pharmacology. Grada, 2015. (Chapter: Drugs used in disorders of coagulation.)

6. Špinar, J. et al.: Cardiology. Galén, 2021.

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