1. Female participant who is pregnant, lactating or planning pregnancy during the course of the trial (women of childbearing potential as determined by the clinician must have a negative urine pregnancy test) 2. Pre-existing significant liver disease or a baseline AST or ALT which is >3x the upper limit of normal 3. A previously established diagnosis of significant pulmonary hypertension defined as a resting pulmonary artery pressure of >50 mmHg on right heart catheter or echocardiography 4. Received invasive mechanical ventilation for > 72 h during current illness, at the time of recruitment into the study 5. In the clinicians’ view, expected to survive < 24 hours 6. Patients who, in the absence of COVID-19, would be unable to give informed consent 7. Hypersensitivity to almitrine 8. A previously established diagnosis of right ventricular dysfunction that is clinically significant in the opinion of the treating physician 9. Hyperlactataemia (lactate >2mM)

1. Female participant who is pregnant, lactating or planning pregnancy during the course of the trial (women of childbearing potential as determined by the clinician must have a negative urine pregnancy test) 2. Pre-existing significant liver disease or a baseline AST or ALT which is >3x the upper limit of normal 3. A previously established diagnosis of significant pulmonary hypertension defined as a resting pulmonary artery pressure of >50 mmHg on right heart catheter or echocardiography 4. Received invasive mechanical ventilation for > 72 h during current illness, at the time of recruitment into the study 5. In the clinicians’ view, expected to survive < 24 hours 6. Patients who, in the absence of COVID-19, would be unable to give informed consent 7. Hypersensitivity to almitrine 8. A previously established diagnosis of right ventricular dysfunction that is clinically significant in the opinion of the treating physician 9. Hyperlactataemia (lactate >2mM)