From the Guidelines
Midodrine should be held if the systolic blood pressure (SBP) is greater than or equal to 160 mmHg, as this threshold is crucial to prevent potential supine hypertension, a known side effect of midodrine 1. This medication is primarily used to treat orthostatic hypotension by causing vasoconstriction and increasing blood pressure. Since midodrine's main effect is to raise blood pressure, administering it when the SBP is already elevated could potentially lead to dangerous hypertension.
When monitoring patients on midodrine, it is essential to check blood pressure before each dose and withhold the medication if SBP exceeds this threshold. It's also advisable to avoid giving midodrine within 4 hours of bedtime to prevent supine hypertension while the patient is lying down. If you need to hold multiple doses due to elevated blood pressure, contact the prescribing provider to reassess the dosing regimen. Patients should be educated to monitor for signs of excessive blood pressure elevation such as severe headache, pounding in ears, blurred vision, or chest pain and to seek medical attention if these occur.
Key considerations for managing midodrine include:
- Monitoring for bradycardia, as midodrine is associated with reflex parasympathetic stimulation 1
- Using midodrine cautiously in patients with CHF and in those using other negative chronotropic agents such as beta-blockers, digoxin and nondihydropyridine CCBs 1
- Avoiding concomitant use with other-adrenergic agents—such as ephedrine, pseudoephedrine and phenylpropanolamine—to prevent aggravating supine hypertension 1
- Being aware that midodrine can antagonize the actions of -adrenergic blockers (such as terazosin, prazosin and doxazosine) and could result in urinary retention 1
Recent guidelines suggest targeting SBP as low as reasonably achievable, with an optimal point of 120 mmHg if tolerated, especially in symptomatic orthostatic hypotension and/or age ≥85 years 1. However, in the context of midodrine use, the primary concern is preventing excessive blood pressure elevation, thus the threshold of 160 mmHg for holding midodrine remains a critical consideration.
From the FDA Drug Label
WARNINGS Supine Hypertension: The most potentially serious adverse reaction associated with midodrine therapy is marked elevation of supine arterial blood pressure (supine hypertension). Systolic pressure of about 200 mmHg were seen overall in about 13. 4% of patients given 10 mg of midodrine. There is no experience in patients with initial supine systolic pressure above 180 mmHg, as those patients were excluded from the clinical trials. Use of midodrine in such patients is not recommended
The FDA drug label does not provide a specific systolic blood pressure (SBP) at which midodrine should be held, but it does state that use of midodrine is not recommended in patients with initial supine systolic pressure above 180 mmHg 2.
From the Research
Midodrine and Systolic Blood Pressure
- The studies provided do not specify a particular systolic blood pressure (SBP) at which midodrine should be held 3, 4, 5, 6, 7.
- However, it is mentioned that supine hypertension is a potential side effect of midodrine therapy, which can occur in up to 25% of patients 5.
- In one study, doses of midodrine were reduced if patients developed erect hypertension (systolic > 180 mmHg or diastolic > 110 mmHg) 7.
- Another study reported that midodrine increased standing systolic blood pressure by 22 mm Hg (28%, p < 0.001 versus placebo), but did not specify a particular SBP at which midodrine should be held 6.
Management of Orthostatic Hypotension
- Midodrine is an effective therapeutic option for the management of various forms of orthostatic hypotension 5.
- The drug has been shown to improve standing systolic blood pressure, standing time, and energy level, and to reduce clinical symptoms of orthostatic hypotension, including dizziness, lightheadedness, and syncope 3, 4, 5, 6.
- The most commonly reported adverse events associated with midodrine therapy are piloerection, pruritus, paraesthesias, urinary retention, and chills 5.