What are the treatment recommendations for a patient experiencing dizziness upon standing with orthostatic hypotension?

Management of Dizziness Upon Standing with Orthostatic Hypotension

Begin with medication review and discontinuation of offending agents, particularly alpha-blockers, sedatives, and unnecessary antihypertensives, followed by nonpharmacologic interventions including increased fluid and salt intake, compression stockings, and physical counterpressure maneuvers; if symptoms persist despite these measures, initiate midodrine as first-line pharmacologic therapy. 1, 2

Initial Assessment and Classification

Before initiating treatment, determine whether the orthostatic hypotension is neurogenic or non-neurogenic by measuring heart rate response:

• Neurogenic orthostatic hypotension: Heart rate increase <15 bpm upon standing, indicating autonomic nervous system dysfunction 1
• Non-neurogenic orthostatic hypotension: Adequate heart rate increase (≥15 bpm), suggesting causes like medications, dehydration, blood loss, or cardiac dysfunction 1

This distinction is critical because neurogenic forms often require more aggressive pharmacologic management and carry risk of supine hypertension 3, 1.

Step 1: Medication Optimization (First Priority)

Immediately review and discontinue or reduce medications that worsen orthostatic hypotension, prioritizing alpha-blockers, sedatives, prostate-specific medications, and unnecessary blood pressure-lowering drugs. 1

Common culprits include:

• Alpha-blockers (prazosin, terazosin, doxazosin) 2
• Antihypertensives in patients with baseline normal or low blood pressure 1
• Sedatives and psychotropic medications 2
• Diuretics causing volume depletion 4

Step 2: Nonpharmacologic Interventions (Universal Application)

All patients should receive nonpharmacologic treatment regardless of symptom severity 5, 4:

Dietary Modifications

• Increase fluid intake to 2-3 liters daily 6
• Increase salt intake (typically 6-10 grams daily unless contraindicated by heart failure or renal disease) 4, 7
• Avoid large meals that can worsen postprandial hypotension 1
• Limit or avoid alcohol 3

Physical Counterpressure Maneuvers

Teach patients acute maneuvers to raise blood pressure when symptoms occur: 1

• Leg crossing while standing
• Squatting
• Arm tensing
• Bending forward at the waist

Compression Garments

• Waist-high compression stockings (30-40 mmHg) are more effective than knee-high stockings 4, 7
• Abdominal binders can be used as an alternative or addition 4

Positional Strategies

• Sleep with head of bed elevated 10-20 degrees to reduce nocturnal pressure natriuresis and minimize supine hypertension 4, 7
• Avoid prolonged standing, especially in warm environments 6
• Rise slowly from supine to sitting to standing positions 4

Step 3: Pharmacologic Treatment (When Nonpharmacologic Measures Fail)

First-Line: Midodrine

Midodrine is the preferred first-line pharmacologic agent for symptomatic orthostatic hypotension that persists despite nonpharmacologic interventions. 2, 4, 8

Dosing:

• Start at 2.5-5 mg three times daily 4
• Standard dose: 10 mg three times daily 2
• Maximum dose: 20 mg three times daily (though higher doses significantly increase supine hypertension risk) 2
• Critical timing: Give last dose 3-4 hours before bedtime to minimize nighttime supine hypertension 2

Mechanism and efficacy:

• Midodrine is converted to desglymidodrine, an alpha-1 agonist that increases vascular tone 2
• Increases standing systolic blood pressure by 15-30 mmHg at 1 hour after 10 mg dose 2
• Effect persists for 2-3 hours 2

Critical warnings:

• Monitor for supine hypertension (systolic BP >200 mmHg occurred in 22% at 10 mg dose and 45% at 20 mg dose) 2
• Patients should avoid lying flat; sleep with head elevated 2
• Use with caution in patients with urinary retention, as it acts on bladder neck alpha-receptors 2
• Reduce starting dose to 2.5 mg in renal impairment 2

Alternative Pharmacologic Options

Fludrocortisone (0.1-0.2 mg daily):

• Increases sodium retention and plasma volume 5, 9
• Caution: Long-term use associated with concerning effects including hypokalemia, edema, and increased intraocular pressure 4
• May be used in combination with midodrine in refractory cases 5

Droxidopa:

• Alternative first-line agent, particularly for neurogenic orthostatic hypotension 4, 8
• Converted to norepinephrine, increasing blood pressure 4

Pyridostigmine:

• May be beneficial as adjunctive therapy 5
• Less effective as monotherapy 5

Critical Pitfalls to Avoid

Supine hypertension in autonomic failure patients:

• These patients experience profound hypotension when standing but severe hypertension when supine, creating a dangerous situation 3
• Supine hypertension subjects them to left ventricular hypertrophy, coronary disease, flash pulmonary edema, heart failure, renal failure, stroke, and sudden death 3
• Never allow patients to take midodrine within 3-4 hours of bedtime 2

Drug interactions:

• Avoid combining midodrine with other vasoconstrictors (phenylephrine, pseudoephedrine, ephedrine) as this markedly increases hypertension risk 2
• Use caution with cardiac glycosides, which may precipitate bradycardia or heart block 2
• MAO inhibitors and linezolid should be avoided with midodrine 2

Pseudohypertension in elderly:

• Rigid calcified arteries may give falsely elevated cuff readings 3
• These patients may be inadvertently overdosed with antihypertensives, causing symptomatic orthostatic hypotension 3

Monitoring and Follow-up

• Measure supine and standing blood pressures at each visit to assess treatment response and detect supine hypertension 1, 4
• Continue midodrine only if patients report significant symptomatic improvement, as clinical benefits beyond blood pressure elevation remain to be fully established 2
• Assess renal and hepatic function before initiating therapy and periodically thereafter 2
• Obtain 12-lead ECG to detect arrhythmias or structural heart disease 1

Treatment Goals

The goal is improving symptoms and functional capacity, not achieving arbitrary blood pressure targets. 8 Focus on:

• Reducing dizziness, lightheadedness, and syncope episodes 1
• Improving standing time and ability to perform daily activities 2, 8
• Minimizing falls risk 4
• Balancing orthostatic hypotension treatment against supine hypertension risk 3, 8