From the Guidelines
Midodrine is effective in managing POTS by increasing blood pressure and reducing symptoms of orthostatic intolerance, and it should be considered as a treatment option for patients with POTS, particularly those with low blood pressure or significant venous pooling. Midodrine works as an alpha-1 adrenergic receptor agonist that causes constriction of blood vessels, particularly in the lower extremities and splanchnic circulation 1. This vasoconstriction reduces venous pooling when standing, which helps maintain blood return to the heart and prevents the excessive heart rate increase characteristic of POTS. Some key points to consider when using midodrine for POTS include:
- The typical starting dose is 2.5-10 mg, with the first dose taken in the morning before getting out of bed and the last dose taken no later than 4 pm 1
- Midodrine may help with orthostatic intolerance, and its use should be considered in conjunction with other nonpharmacological interventions, such as salt and fluid loading, elevation of the head of the bed, and use of support stockings 1
- Patients should be monitored regularly for side effects, including supine hypertension, and should avoid taking midodrine before lying down for extended periods. Overall, midodrine can be a useful treatment option for patients with POTS, particularly those with low blood pressure or significant venous pooling, and its use should be considered as part of a comprehensive treatment plan that includes nonpharmacological interventions and other pharmacological therapies as needed 1.
From the FDA Drug Label
Midodrine forms an active metabolite, desglymidodrine, that is an alpha1-agonist, and exerts its actions via activation of the alpha-adrenergic receptors of the arteriolar and venous vasculature, producing an increase in vascular tone and elevation of blood pressure. Administration of midodrine results in a rise in standing, sitting, and supine systolic and diastolic blood pressure in patients with orthostatic hypotension of various etiologies Standing systolic blood pressure is elevated by approximately 15 to 30 mmHg at 1 hour after a 10 mg dose of midodrine, with some effect persisting for 2 to 3 hours.
Midodrine works in POTS (Postural Orthostatic Tachycardia Syndrome) by increasing vascular tone and elevating blood pressure through its active metabolite, desglymidodrine, which is an alpha1-agonist. The key effects of midodrine include:
- Increasing vascular tone
- Elevating blood pressure
- Producing a rise in standing, sitting, and supine systolic and diastolic blood pressure in patients with orthostatic hypotension of various etiologies, including POTS. The increase in blood pressure helps to alleviate symptoms of POTS, such as dizziness and lightheadedness, by improving blood flow to the brain and other organs 2.
From the Research
Mechanism of Action
- Midodrine is a prodrug that undergoes enzymatic hydrolysis to the selective alpha 1-adrenoceptor agonist desglymidodrine after oral administration 3.
- It works by increasing standing systolic blood pressure and improving symptoms of orthostatic hypotension, such as dizziness, light-headedness, and syncope 3, 4.
Efficacy in POTS
- Midodrine has been shown to suppress tachycardia in patients with Postural Orthostatic Tachycardia Syndrome (POTS) 5.
- It improves standing time in patients with Orthostatic Intolerance (OI) 5.
- Combination therapy with midodrine and octreotide may be more effective than monotherapy in improving standing time and suppressing tachycardia in patients with POTS 5.
Dosage and Administration
- The recommended dosage of midodrine for the treatment of neurogenic orthostatic hypotension is 10 mg, prescribed two to three times daily 6.
- The final daily dose of midodrine should be taken at least 4 hours before bedtime to reduce the risk of supine hypertension 3.