What are the blood pressure parameters for midodrine (Midodrine hydrochloride)?

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 hydrochloride tablets are indicated for the treatment of symptomatic orthostatic hypotension (OH) Because midodrine hydrochloride tablets can cause marked elevation of supine blood pressure (BP>200 mmHg systolic)

The blood pressure parameters for midodrine (Midodrine hydrochloride) are:

• Elevation of standing systolic blood pressure: approximately 15 to 30 mmHg at 1 hour after a 10 mg dose
• Supine blood pressure: can be elevated to >200 mmHg systolic
• Sitting and supine blood pressure: rose 16/8 and 20/10 mmHg, respectively, on average 1
• Exclusion criteria: pre-existing sustained supine hypertension above 180/110 mmHg 1

From the Research

Midodrine should be withheld if the systolic blood pressure is above 160 mmHg or the diastolic blood pressure exceeds 100 mmHg. Before initiating midodrine therapy, baseline blood pressure should be measured in both supine and standing positions. During treatment, regular blood pressure monitoring is essential, particularly within 1-2 hours after dosing when peak effects occur. Patients should be instructed to check their blood pressure before each dose and avoid taking midodrine if their readings exceed these parameters. This cautious approach is necessary because midodrine is an alpha-1 adrenergic agonist that causes vasoconstriction, which raises blood pressure to treat orthostatic hypotension. Excessive blood pressure elevation can increase the risk of cardiovascular events, especially in patients with underlying heart disease or hypertension. If supine hypertension develops, dose reduction, timing adjustments (avoiding evening doses), or elevating the head of the bed may help manage this side effect while maintaining the benefits for orthostatic symptoms.

Key Considerations

• The most recent and highest quality study 2 suggests that midodrine can increase standing systolic blood pressure, but the quality of evidence is limited by imprecision, heterogeneity, and increased risk of bias.
• Midodrine has been shown to be effective in increasing orthostatic blood pressure and ameliorating symptoms in patients with neurogenic orthostatic hypotension, with a significant linear relation between midodrine dosage and mean systolic blood pressure 3.
• The risk of supine hypertension, which is associated with midodrine therapy in up to 25% of patients, can be reduced by taking the final daily dose at least 4 hours before bedtime 4.
• Patients should be closely monitored for adverse events, including piloerection, pruritus, paraesthesias, urinary retention, and chills, which are commonly reported with midodrine therapy 4.

Monitoring and Management

• Regular blood pressure monitoring is essential to minimize the risk of excessive blood pressure elevation and cardiovascular events.
• Patients should be instructed to check their blood pressure before each dose and avoid taking midodrine if their readings exceed the recommended parameters.
• If supine hypertension develops, dose reduction, timing adjustments, or elevating the head of the bed may help manage this side effect while maintaining the benefits for orthostatic symptoms.