From the Guidelines
Midodrine is a medication that can be beneficial in patients with syncope due to neurogenic orthostatic hypotension (OH), as it improves symptoms of OH by increasing standing blood pressure. According to the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1, midodrine has a dose-dependent effect, which may be limited by supine hypertension, and common side effects include scalp tingling, piloerection, and urinary retention.
Key Points about Midodrine
- Midodrine works as an alpha-1 adrenergic receptor agonist that constricts blood vessels, increasing blood pressure 1.
- The typical dosage and administration schedule are crucial to balance efficacy with the risk of supine hypertension, suggesting doses should be taken during waking hours.
- Common side effects and potential contraindications, such as severe heart disease or acute kidney failure, should be considered when prescribing midodrine.
- Regular blood pressure monitoring is essential, especially when initiating treatment or adjusting the dosage of midodrine 1.
Considerations for Use
- The use of midodrine may be limited by its side effects, and alternative treatments such as droxidopa, fludrocortisone, or pyridostigmine might be considered based on patient-specific factors and the underlying cause of neurogenic OH 1.
- Patient education on the proper use of midodrine, including the timing of doses and the importance of monitoring blood pressure, is vital for safe and effective management of neurogenic OH.
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. Midodrine hydrochloride tablets, USP Pharmacological Classification: Vasopressor/Antihypotensive
Midodrine is a vasopressor/antihypotensive medication that works by forming an active metabolite, desglymidodrine, which is an alpha1-agonist. It 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 2, 2, 2.
From the Research
Definition and Mechanism of Midodrine
- Midodrine is a peripheral alpha-adrenergic agonist used in the clinical management of patients with orthostatic hypotension or hypotension secondary to other clinical conditions or drug therapies 3.
- It is almost completely absorbed after oral administration and undergoes enzymatic hydrolysis to form its pharmacologically active metabolite, de-glymidodrine 3, 4.
Therapeutic Use of Midodrine
- Midodrine is used to increase standing blood pressure and improve symptoms of orthostatism, such as weakness, syncope, blurred vision, and fatigue, without any associated cardiac stimulation 3.
- Comparative studies have shown midodrine to be clinically at least as effective as other sympathomimetic agents and dihydroergotamine in the management of orthostatic hypotension 3, 4.
- Midodrine appears to cause less frequent and severe adverse effects associated with alpha-receptor agonism, such as piloerection and urinary hesitancy 3.
Efficacy and Safety of Midodrine
- Midodrine has been shown to be effective in improving orthostatic blood pressure drop and ameliorating orthostatic symptoms in patients with neurogenic orthostatic hypotension 5, 6.
- The drug is well-tolerated, with the most commonly reported adverse events being piloerection, pruritus, paraesthesias, urinary retention, and chills 4.
- The risk of supine hypertension associated with midodrine therapy can be reduced by taking the final daily dose at least 4 hours before bedtime 4.