Pulmonary embolism in renal impairment

Patient B-217 is a 70-year-old man, weight 64 kg, admitted to the emergency department with sudden-onset pleuritic chest pain and breathlessness. He reports a two-day history of right calf swelling and tenderness. He has a background of hypertension, type 2 diabetes mellitus and chronic kidney disease. His regular medications are amlodipine 5 mg once daily, metformin 500 mg twice daily and bisoprolol 2.5 mg once daily. He has no known allergies. On examination, he is tachypnoeic at 22 breaths per minute, heart rate 110 beats per minute, blood pressure 126/78 mmHg, oxygen saturation 90% on room air, temperature 37.2°C. The right calf is swollen, warm and tender. The chest is clear on auscultation, heart sounds normal. An ECG shows sinus tachycardia. Chest radiograph shows no consolidation or pleural effusion. D-dimer is elevated. CT pulmonary angiogram confirms a thrombus in the right main pulmonary artery. Blood tests: haemoglobin 13.5 g/dL, white cell count 9.1 x10^9/L, platelets 220 x10^9/L, urea 18 mmol/L, creatinine 2.6 mg/dL, eGFR 24 mL/min/1.73m², liver function tests normal. Your task: prescribe the immediate anticoagulant treatment. State the drug name, dose, route and frequency.