How is postural hypotension treated?

Treatment of Postural Hypotension

Begin with non-pharmacological interventions including increased fluid intake (2-3 liters daily) and salt consumption (6-10g daily), combined with physical counter-maneuvers and compression garments; if symptoms persist despite these measures, initiate midodrine 2.5-5mg three times daily as first-line pharmacological therapy, with fludrocortisone 0.1mg daily as an alternative or adjunct. 1

Initial Non-Pharmacological Management

The foundation of treatment prioritizes lifestyle modifications before medications:

• Increase fluid intake to 2-3 liters daily unless contraindicated by heart failure 1
• Increase salt consumption to 6-10g daily (approximately 1-2 teaspoons of table salt) if not contraindicated 1, 2
• Acute water ingestion of ≥480 mL provides temporary relief with peak effect at 30 minutes after consumption; notably, plain water is more effective than salt water for acute blood pressure elevation 1, 3
• Elevate the head of bed by 10 degrees during sleep to prevent nocturnal polyuria, maintain favorable fluid distribution, and reduce supine hypertension 1
• Implement smaller, more frequent meals to reduce post-prandial hypotension 1

Physical Counter-Maneuvers and Compression

• Teach leg crossing, squatting, stooping, and muscle tensing during symptomatic episodes, particularly effective in patients under 60 years with prodromal symptoms 1, 2
• Use waist-high compression stockings (30-40 mmHg) and abdominal binders to reduce venous pooling 1
• Advise gradual staged movements with postural changes rather than rapid position transitions 1

Medication Review and Adjustment

Before initiating pressor agents, address reversible causes:

• Discontinue or switch medications that worsen orthostatic hypotension including diuretics, alpha-1 adrenergic blockers, and vasodilators rather than simply reducing doses 1
• For patients requiring antihypertensive therapy, switch to long-acting dihydropyridine calcium channel blockers (such as amlodipine) or RAS inhibitors as first-line agents 1
• Avoid RAS blockers in patients with isolated orthostatic hypotension due to vasodilatory effects that exacerbate postural blood pressure drops 1

First-Line Pharmacological Treatment: Midodrine

Midodrine is the first-line pharmacological agent with the strongest evidence base among pressor agents for orthostatic hypotension 1, 4:

• Initial dose: 2.5-5mg three times daily, with the last dose at least 3-4 hours before bedtime (no later than 6 PM) to prevent supine hypertension 1, 4
• Mechanism: Alpha-1 adrenergic agonist that increases vascular tone through arteriolar and venous constriction 4
• Expected effect: Increases standing systolic BP by 15-30 mmHg for 2-3 hours after dosing 1, 4
• FDA indication: Approved for symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite non-pharmacologic treatment 4

Midodrine Precautions

• Monitor for supine hypertension (BP >200 mmHg systolic can occur); measure blood pressure in supine position regularly 4
• Use cautiously in older males due to potential urinary retention from alpha-adrenergic effects on bladder neck 1, 4
• Avoid in patients with severe renal impairment without dose adjustment; start at 2.5mg if renal function is compromised 4
• Watch for bradycardia: discontinue if pulse slowing, increased dizziness, or syncope occurs 4

Second-Line Pharmacological Treatment: Fludrocortisone

Fludrocortisone is an effective alternative or adjunct when midodrine alone provides insufficient symptom control 1, 2:

• Initial dose: 0.05-0.1mg once daily, titrate individually to 0.1-0.3mg daily (maximum 1.0mg daily) 1, 5
• Mechanism: Mineralocorticoid that increases plasma volume through sodium retention and has direct vessel wall effects 1, 5
• Evidence quality: Very low-certainty evidence from small, short-term trials, but widely used based on clinical experience 6

Fludrocortisone Monitoring and Contraindications

• Avoid in active heart failure or significant cardiac dysfunction 1
• Contraindicated with pre-existing supine hypertension 1
• Monitor electrolytes periodically for hypokalemia due to mineralocorticoid effects 1
• Watch for peripheral edema, particularly in patients with low serum albumin 5
• Use cautiously with low serum albumin as edema risk increases significantly 5

Combination Therapy

• For non-responders to monotherapy, consider combining midodrine and fludrocortisone 1
• Balance the benefits of increasing standing blood pressure against the risk of worsening supine hypertension 1

Alternative Pharmacological Options

Droxidopa

• FDA-approved for neurogenic orthostatic hypotension, particularly effective in Parkinson's disease, pure autonomic failure, and multiple system atrophy 1
• May reduce falls in these populations 1

Pyridostigmine

• Beneficial for refractory orthostatic hypotension in elderly patients who have not responded to other treatments 1
• Fewer side effects than alternatives like fludrocortisone, though common adverse effects include nausea, vomiting, abdominal cramping, and sweating 1

Treatment Goals and Monitoring

• The therapeutic objective is minimizing postural symptoms and improving functional capacity, not restoring normotension 1
• Measure blood pressure after 5 minutes lying/sitting, then at 1 and 3 minutes after standing to document orthostatic changes 7, 1
• Orthostatic hypotension is defined as a reduction of systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing 7, 2
• Monitor for supine hypertension development, which can cause end-organ damage including left ventricular hypertrophy, stroke, and renal failure 7, 1
• Reassess within 1-2 weeks after medication changes 1

Special Populations

Hemodialysis Patients

• Longer weekly treatment time (5 hours per session, 3 times per week) causes less hypotension during dialysis and less postdialysis postural hypotension compared to shorter sessions 7
• Midodrine is removed by dialysis; timing of administration should account for this 4

Diabetic Patients

• Assess for cardiovascular autonomic neuropathy in diabetic patients presenting with orthostatic hypotension 1
• Symptoms are often rare despite significant blood pressure drops and may include dizziness, weakness, blurred vision, and tiredness 8
• Prognosis is poorer in diabetic patients with postural hypotension compared to those with autonomic neuropathy without postural hypotension 8

Critical Pitfalls to Avoid

• Do not advise water restriction without sodium restriction: excessive sodium intake stimulates thirst through increased ECF osmolality, making isolated water restriction futile and causing unnecessary suffering 7
• Do not add salt to water for acute relief: plain water produces a greater pressor response than salt water, likely due to gastrointestinal osmolality effects on sympathetic activation 3
• Do not continue midodrine if patients do not report significant symptomatic improvement after initiation 4
• Do not dose midodrine after 6 PM: this prevents supine hypertension during sleep 1, 4