From the Guidelines
Midodrine is a medication used to treat orthostatic hypotension, specifically neurogenic orthostatic hypotension, by improving symptoms and increasing standing blood pressure through its alpha-1 adrenergic agonist activity. According to the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1, midodrine can be beneficial in patients with syncope due to neurogenic orthostatic hypotension. The guideline suggests that midodrine improves symptoms of orthostatic hypotension in patients with neurogenic orthostatic hypotension, with a dose-dependent effect corresponding to an increase in standing blood pressure.
Some key points to consider when using midodrine include:
- The typical dosage and administration schedule
- Common side effects such as scalp tingling, piloerection, and urinary retention
- Potential limitations, including supine hypertension
- The importance of monitoring blood pressure regularly, especially when starting treatment or adjusting dosage
It's also important to note that midodrine is not the only treatment option for orthostatic hypotension, and other medications such as droxidopa, fludrocortisone, and pyridostigmine may also be beneficial in certain cases 1. However, midodrine is a recommended treatment option for neurogenic orthostatic hypotension, and its use should be considered in patients with symptomatic orthostatic hypotension.
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 is a prodrug that is converted to its active metabolite, desglymidodrine, which acts as an alpha1-agonist to increase vascular tone and blood pressure.
- It is used to treat orthostatic hypotension of various etiologies.
- The absolute bioavailability of midodrine (measured as desglymidodrine) is 93% 2
- Midodrine has no clinically significant effect on standing or supine pulse rates in patients with autonomic failure 2
From the Research
Definition and Mechanism of Action
- 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 a prodrug that undergoes enzymatic hydrolysis to form its pharmacologically active metabolite, desglymidodrine, after oral administration 4.
Therapeutic Use
- Midodrine is effective in increasing standing blood pressure and improving symptoms of orthostatism, such as weakness, syncope, blurred vision, and fatigue, without associated cardiac stimulation 3.
- It has been shown to be clinically at least as effective as other sympathomimetic agents and dihydroergotamine in the management of orthostatic hypotension 3, 4.
- Midodrine is also used to target vasoplegic conditions such as intradialytic hypotension in the end-stage renal disease population, refractory ascites in cirrhotic patients, and hepatorenal syndrome 5.
Adverse Effects
- The most commonly experienced adverse effects of midodrine include piloerection, gastrointestinal disorders, and cardiovascular complaints, which are generally mild and can be controlled by reducing the dosage 3.
- Other adverse effects associated with midodrine therapy include pruritus, paraesthesias, urinary retention, and chills 4, 5.
- The risk of supine hypertension, which is associated with midodrine therapy, can be reduced by taking the final daily dose at least 4 hours before bedtime 4.
Patient Response
- Midodrine is effective in the treatment of orthostatic hypotension only in patients with significant preservation of autonomic reflexes 6.
- In patients with markedly impaired baroreceptor mechanisms, treatment with midodrine may produce extracellular fluid volume depletion and exacerbate orthostatic hypotension 6.