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) Pre-existing significant liver disease or a baseline AST or ALT which is >3x the upper limit of normal. A previously established diagnosis of significant pulmonary hypertension defined as a resting pulmonary artery pressure of >50 mmHg on right heart catheter or echocardiography. Received invasive mechanical ventilation for >72h during current illness, at the time of recruitment into the study In the clinicians’ view, expected to survive <24 hours Patients who, in the absence of Covid-19, would be unable to give informed consent. Hypersensitivity to almitrine

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) Pre-existing significant liver disease or a baseline AST or ALT which is >3x the upper limit of normal. A previously established diagnosis of significant pulmonary hypertension defined as a resting pulmonary artery pressure of >50 mmHg on right heart catheter or echocardiography. Received invasive mechanical ventilation for >72h during current illness, at the time of recruitment into the study In the clinicians’ view, expected to survive <24 hours Patients who, in the absence of Covid-19, would be unable to give informed consent. Hypersensitivity to almitrine