Rivaroxaban (Xarelto) 💊

💊 Rivaroxaban is an oral direct Factor Xa inhibitor. ✅ Indicated in non-rheumatic AF with one or more risk factors: previous stroke/TIA, heart failure, age >75, diabetes, or hypertension. ⚠️ Always check the BNF link here for the latest prescribing guidance.

📖 About

• Alternative to warfarin for stroke prevention in non-valvular AF.
• Also used in DVT, PE, and post-operative VTE prophylaxis.
• Convenient fixed dosing, no INR monitoring required.
• Cost: ~£3/day in the UK 💷.

⚙️ Mechanism of Action

• Factor Xa normally converts prothrombin → thrombin → fibrin clot.
• Rivaroxaban directly inhibits Factor Xa (both free and clot-bound in the prothrombinase complex).
• Half-life ~12 hours, with ~66% renal excretion → dose adjustments needed in renal impairment.

📌 Indications & Doses

• Non-valvular AF: - CrCl >50 mL/min → 20 mg PO OD with evening meal. - CrCl 15–50 mL/min → 15 mg PO OD with evening meal.
• VTE prophylaxis: - Knee replacement → 10 mg OD for 2 weeks (start 6–10h post-op). - Hip replacement → 10 mg OD for 5 weeks (start 6–10h post-op).
• DVT/PE treatment: - 15 mg BD for 21 days, then 20 mg OD with food. - Some may continue 15 mg OD for extended prevention.
• ACS (adjunct): 2.5 mg BD, usually for 12 months.

🔄 Interactions

• ↑ Bleeding risk with: Aspirin, P2Y12 inhibitors (clopidogrel, ticagrelor), other anticoagulants, fibrinolytics, NSAIDs.
• Avoid with CYP3A4 inducers: Carbamazepine, Phenytoin, Rifampicin, St. John’s wort.
• Avoid with CYP3A4 inhibitors: Ketoconazole, Ritonavir, Clarithromycin, Erythromycin, Fluconazole.

⚠️ Cautions

• Renal impairment (dose-adjust or avoid if severe).
• Liver disease with coagulopathy.
• High falls risk → weigh up bleeding vs stroke risk.

⛔ Contraindications

• Active pathological bleeding.
• Recent major surgery (brain, spine, ophthalmic).
• Recent intracranial haemorrhage.
• High-risk lesions (GI ulcers, oesophageal varices, aneurysm, malignant tumours with bleeding risk).
• Severe hypersensitivity reaction.

💥 Side Effects

• Bleeding (most serious) → GI, intracranial, or soft tissue.
• GI upset: abdominal pain, nausea, constipation, vomiting.
• Neurological: headache, dizziness (sometimes related to anaemia from bleeding).
• Falls → may worsen risk of traumatic intracranial bleed.

💡 Clinical Pearls

- No routine INR monitoring, but renal function and haemoglobin must be checked regularly. - Always assess CHA₂DS₂-VASc vs HAS-BLED scores before prescribing. - Safer than warfarin in most patients, but no easy reversal (andexanet alfa exists but limited availability in UK). - Counsel patients: 💬 "Take with food, never miss a dose, and report any unexplained bleeding/bruising."