- hypotension (sap < 100 mmhg or dap < 50 mmhg or map < 65 mmhg) - hyperkalemia (> 5.5 mmol/l) - acute kidney injury (urine output < 0.5 ml/kg/hr and new creatinine > 200 mmol/l, or increase > 100 mmol/l, or gfr < 30 ml/min) - use of arb/acei within 7 days of presentation - pregnant or breastfeeding - have a known allergy to losartan or any component of the drug product - have written legal document to withhold life-sustaining (patients not wishing to receive cardiopulmonary resuscitation (cpr) can participate if other medical treatments will be given) - have signed a do no resuscitate (dnr) form

- hypotension (sap < 100 mmhg or dap < 50 mmhg or map < 65 mmhg) - hyperkalemia (> 5.5 mmol/l) - acute kidney injury (urine output < 0.5 ml/kg/hr and new creatinine > 200 mmol/l, or increase > 100 mmol/l, or gfr < 30 ml/min) - use of arb/acei within 7 days of presentation - pregnant or breastfeeding - have a known allergy to losartan or any component of the drug product - have written legal document to withhold life-sustaining (patients not wishing to receive cardiopulmonary resuscitation (cpr) can participate if other medical treatments will be given) - have signed a do no resuscitate (dnr) form