Table 1 Study exclusion criteria

Clinical evidence of inadequate tissue oxygenation

For safety consideration, patients with ongoing shock excluded.

Hypovolemic shock or hypotension due to adrenal insufficiency (based on clinical suspicion or available routine testing)

Treatable cause of hypotension.

Clinical evidence of liver failure

Midodrine metabolism occurs predominantly in liver.

Pregnancy

No safety data available.

Chronic renal failure (serum creatinine >2 mg/dL, or 180umol/L)

Midodrine and its active metabolite are almost completely excreted in urine. Drug accumulation may occur, and for this trial dose adjustment is not possible.

Severe organic heart disease (ejection fraction less than 30%)

Contraindicated due to higher risk of arrhythmias

Acute urinary retention

Accumulation of drug may occur as usually almost completed excreted in urine.

Pheochromocytoma (based on clinical suspicion)

Contraindication.

Thyrotoxicosis (based on clinical suspicion)

Contraindication.

Co-enrolment in another vasopressor clinical trial

Confounding factor.

Midodrine as pre-admission medication

Confounding factor.

Any known allergies to midodrine

Contraindication.

Bradycardia (HR <50/min)

Higher likelihood of symptomatic bradycardia.

No enteral route available

Oral preparation.