What are the drugs and their dosages for a patient with postural (low blood pressure) hypotension?

Pharmacological Management of Postural Hypotension

For patients with postural hypotension, midodrine (10 mg up to three times daily, with the last dose at least 3-4 hours before bedtime) is the first-line pharmacological treatment, followed by droxidopa if midodrine is ineffective. 1, 2

First-Line Pharmacological Therapy

Midodrine

• FDA-approved for orthostatic hypotension treatment 1, 2
• Dosage: Start with 2.5-5 mg three times daily, titrate up to 10 mg three times daily 2
• Timing: First dose upon waking, subsequent doses at 3-4 hour intervals, with last dose at least 3-4 hours before bedtime to avoid supine hypertension 1, 2
• Mechanism: Peripheral selective α1-adrenergic agonist causing arteriolar and venous constriction 1, 2
• Effects: Increases standing systolic blood pressure by 15-30 mmHg within 1 hour of administration, with effects lasting 2-3 hours 2
• Common side effects: Supine hypertension, pilomotor reactions (goosebumps), pruritus, urinary retention 1, 2

Droxidopa

• FDA-approved alternative for orthostatic hypotension 1, 3
• Dosage: Start at 100 mg three times daily, titrate by 100 mg increments every 24-48 hours to maximum of 600 mg three times daily 3
• Timing: Three times daily schedule with last dose at least 3 hours before bedtime 3
• Mechanism: Synthetic amino acid that converts to norepinephrine, increasing blood pressure 3
• Effects: Reduces dizziness and increases standing systolic blood pressure 3
• Caution: Effectiveness beyond 2 weeks uncertain; requires periodic reevaluation 3

Second-Line Pharmacological Options

Fludrocortisone

• Mineralocorticoid that increases sodium retention and expands fluid volume 1
• Dosage: 0.1-0.3 mg once daily 1
• Caution: Monitor for fluid retention, hypokalemia, and worsening supine hypertension 1

Other Pharmacological Options

• Clonidine/Guanfacine: Useful for patients with high supine blood pressure; take at bedtime 1
• Short-acting β-blockers: Atenolol or metoprolol tartrate for patients with elevated supine blood pressure 1
• Short-acting calcium channel blockers: Isradipine for nighttime blood pressure control 1
• Pyridostigmine: Alternative for patients who don't respond to first-line treatments 4
• α-Lipoic acid: May be considered for diabetic patients with painful neuropathy and orthostatic hypotension 1

Non-Pharmacological Management (Essential First Step)

• Fluid and salt intake: Target 2-3 L of fluids and 10g of salt daily 1, 4
• Rapid water ingestion: 500 ml of cool water can quickly combat orthostatic symptoms 1
• Physical countermeasures: Leg crossing, squatting, and muscle tensing during position changes 1
• Compression garments: Abdominal binders and/or compression stockings to reduce venous pooling 1
• Sleeping position: Elevate head of bed by 10° to prevent nocturnal polyuria and maintain better fluid distribution 1
• Meal modifications: Small, frequent meals with lower carbohydrate content to minimize post-prandial hypotension 1
• Medication review: Identify and discontinue medications that worsen orthostatic hypotension when possible 1, 5
• Staged movements: Gradual position changes from lying to sitting to standing 1

Special Considerations

For Diabetic Patients

• Consider underlying autonomic neuropathy as a cause 1
• Optimize glucose control to prevent progression of autonomic dysfunction 1
• Avoid medications that worsen orthostatic symptoms (e.g., GLP-1 RAs, pramlintide) 1

For Elderly Patients

• Start with lower doses and titrate more gradually 1
• Monitor closely for supine hypertension 1
• Consider polypharmacy effects and medication interactions 5, 4

For Heart Failure Patients

• Prioritize SGLT2 inhibitors and MRAs as they have minimal impact on blood pressure 1
• Space out medications to reduce synergistic hypotensive effects 1
• Consider reducing doses of ACE inhibitors/ARBs before β-blockers if symptomatic hypotension occurs 1

Treatment Algorithm

1. Initial approach: Implement non-pharmacological measures for all patients 1, 5, 4
2. If symptoms persist: Start midodrine at low dose (2.5-5 mg TID) and titrate upward 1, 2
3. If inadequate response: Add or switch to droxidopa 1, 3
4. For refractory cases: Consider combination therapy with fludrocortisone 1
5. For nocturnal supine hypertension: Add bedtime short-acting antihypertensives 1

Remember that the goal of treatment is to minimize postural symptoms rather than to restore normotension, as excessive supine hypertension can lead to additional complications 1, 6.