What are the effects of midodrine when lying down?

From the Guidelines

Midodrine should not be taken when lying down, and patients should remain upright for at least 4 hours after each dose to avoid supine hypertension. This medication works by constricting blood vessels to raise blood pressure, which is helpful for people with orthostatic hypotension (low blood pressure when standing up) 1. When lying down, this blood vessel constriction can cause dangerously high blood pressure since your body doesn't need to work against gravity. Some key points to consider when taking midodrine include:

• Taking the medication during daytime hours (morning, midday, and late afternoon, but not after 6 PM) to prevent high blood pressure while sleeping 1
• Elevating the head of the bed at least 30 degrees if you've already taken midodrine and need to lie down 1
• Following your doctor's specific instructions about timing your doses to avoid needing to lie down afterward
• Being aware of the potential side effects of midodrine, such as pilomotor reactions, pruritus, supine hypertension, bradycardia, gastrointestinal symptoms, and urinary retention 1 If you experience severe headache, pounding heartbeat, or other concerning symptoms while lying down after taking midodrine, contact your healthcare provider immediately. Additionally, other treatments such as physical counter-pressure maneuvers, compression garments, and increased fluid and salt intake may be beneficial in managing orthostatic hypotension 1.

From the FDA Drug Label

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. Supine and sitting blood pressure rose 16/8 and 20/10 mmHg, respectively, on average

Laying down after taking midodrine:

• The FDA drug label warns about supine hypertension as a potentially serious adverse reaction associated with midodrine therapy.
• Supine systolic pressure can be elevated by midodrine, with systolic pressures of about 200 mmHg seen in about 13.4% of patients given 10 mg of midodrine 2.
• It is essential to monitor supine and sitting blood pressures in patients maintained on midodrine to minimize the risk of uncontrolled hypertension and cardiovascular events, particularly stroke.
• Patients with pre-existing sustained supine hypertension above 180/110 mmHg were routinely excluded from clinical trials, and the use of midodrine in such patients is not recommended 2.

From the Research

Midodrine and Laying Down

• Midodrine is a prodrug that is converted to desglymidodrine, a selective alpha 1-adrenoceptor agonist, after oral administration 3.
• It is used to treat orthostatic hypotension, a condition characterized by a significant drop in blood pressure when standing up from a lying down or sitting position.
• Studies have shown that midodrine can increase standing systolic blood pressure and improve symptoms of orthostatic hypotension, such as dizziness and lightheadedness 3, 4, 5.
• However, midodrine can also cause supine hypertension, which can be a concern when laying down 3, 5.
• To minimize the risk of supine hypertension, it is recommended to take the final daily dose of midodrine at least 4 hours before bedtime 3.

Combination Therapy with Midodrine

• Midodrine can be used in combination with other medications, such as pyridostigmine, to treat orthostatic hypotension 4, 6.
• Combination therapy with midodrine and pyridostigmine has been shown to be effective in improving orthostatic blood pressure and symptoms 4, 6.
• Pyridostigmine has been proposed as a potential treatment alternative for orthostatic hypotension, as it may improve orthostatic blood pressure without worsening supine hypertension 6.

Safety and Efficacy of Midodrine

• Midodrine is generally well-tolerated, but it can cause adverse events such as piloerection, pruritus, and urinary retention 3, 5.
• The efficacy and safety of midodrine for orthostatic hypotension have been evaluated in several clinical trials, but the quality of evidence is limited by imprecision, heterogeneity, and increased risk of bias 5.
• Further studies are needed to fully evaluate the efficacy and safety of midodrine for orthostatic hypotension, particularly in combination with other medications 4, 6, 5.