Midodrine is NOT contraindicated in pulmonary hypertension treatment
Midodrine is not listed as a contraindication in pulmonary hypertension (PH) treatment guidelines, though it is not a treatment for PH itself—rather, it is used to manage orthostatic hypotension and intradialytic hypotension that may occur in patients who happen to have PH. 1, 2
Understanding Midodrine's Role
Midodrine is an alpha-1 adrenergic receptor agonist that causes peripheral vasoconstriction, increasing systemic vascular resistance and blood pressure. 1 Its FDA-approved indication is symptomatic orthostatic hypotension, not pulmonary hypertension treatment. 1
Key Clinical Context
- Midodrine does not treat pulmonary hypertension—it addresses systemic hypotension through peripheral arterial and venous constriction. 1
- The drug is commonly used in hemodialysis patients for intradialytic hypotension, including those who may have concurrent PH. 1, 3
- In one reported case, a patient with pulmonary arterial hypertension (PAH) on treprostinil (a pulmonary vasodilator) developed severe systemic hypotension and successfully received high-dose midodrine (up to 90 mg daily) without adverse effects on their PH. 3
Important Caveats and Monitoring
Cardiovascular Effects to Monitor
Patients receiving midodrine require monitoring for reflex bradycardia, which occurs through baroreceptor-mediated vagal stimulation in response to increased blood pressure. 1, 2 This is particularly important when combining midodrine with:
- Beta-blockers
- Non-dihydropyridine calcium channel blockers
- Digoxin
- Other negative chronotropic agents 2
Supine Hypertension Risk
Avoid administering midodrine within 4 hours of bedtime to minimize supine hypertension, which occurs in up to 25% of patients. 1, 2 Discontinue if supine systolic BP exceeds 180 mmHg or diastolic exceeds 110 mmHg. 2
Contraindications That Actually Exist
While PH is not a contraindication, midodrine should be avoided in:
- Severe organic heart disease (though not specifically PH)
- Acute kidney disease
- Urinary retention
- Pheochromocytoma
- Thyrotoxicosis 1
Clinical Decision-Making
If a patient with pulmonary hypertension develops orthostatic hypotension or intradialytic hypotension requiring treatment, midodrine can be safely used with appropriate monitoring for bradycardia and supine hypertension. 1, 2, 3 The standard dosing is 2.5-5 mg three times daily, with the last dose at least 4 hours before bedtime. 2
For dialysis patients with PH, a single 5 mg dose can be given 30 minutes before dialysis to prevent intradialytic hypotension. 2, 3
Common Pitfall to Avoid
Do not confuse midodrine with pulmonary vasodilators used to treat PAH (such as prostacyclins, endothelin receptor antagonists, or phosphodiesterase-5 inhibitors). 4 Midodrine increases systemic vascular resistance and does not directly affect pulmonary vascular resistance. 1