What medications are used to treat hypotension?

Medications for Hypotension

Norepinephrine is the first-line vasopressor for treating hypotension, targeting a mean arterial pressure (MAP) ≥65 mmHg, with initial dosing of 0.02 mcg/kg/min titrated up to 0.1-0.2 mcg/kg/min. 1, 2, 3

Context-Specific Treatment Approach

The medication choice for hypotension depends critically on the underlying etiology and clinical context:

Acute Hypotension with Shock (Septic, Cardiogenic, Distributive)

Initial fluid resuscitation must precede or accompany vasopressor therapy:

• Administer a minimum of 30 mL/kg of crystalloids (lactated Ringer's or normal saline) as initial fluid challenge in patients with suspected hypovolemia 1, 4
• Continue fluid administration as long as hemodynamic parameters improve (blood pressure, heart rate, peripheral perfusion) 1, 4
• In septic shock specifically, more rapid administration and greater fluid volumes may be required 1

Vasopressor therapy algorithm:

• First-line: Norepinephrine 0.02-0.2 mcg/kg/min via central line (can start peripherally while awaiting central access) to maintain MAP ≥65 mmHg 1, 2, 3
• Second-line additions if MAP target not achieved:
  • Add vasopressin 0.03 units/min (not as monotherapy) to raise MAP or reduce norepinephrine dose 1, 2
  • Add epinephrine when additional agent needed, particularly with myocardial dysfunction due to inotropic effect 1, 2
• Avoid dopamine except in highly selected patients with low risk of tachyarrhythmias and absolute or relative bradycardia 1, 2
• Avoid phenylephrine except when norepinephrine causes serious arrhythmias, cardiac output is known to be high with persistently low blood pressure, or as salvage therapy 1

Cardiogenic Shock with Low Cardiac Output

After stabilizing blood pressure with norepinephrine:

• Consider dobutamine 2.5-10 mcg/kg/min if evidence of low cardiac output despite adequate preload 1, 5, 4
• Dobutamine causes tachycardia and may induce myocardial ischemia and arrhythmias; use is reserved for severe reduction in cardiac output compromising vital organ perfusion 1
• Alternative inotropes like milrinone may cause less tachycardia than dobutamine in patients with preserved blood pressure 5

Hemorrhagic/Trauma-Related Hypotension

Fundamentally different approach:

• Prioritize restricted volume replacement with permissive hypotension, targeting systolic BP 80-90 mmHg until bleeding is controlled 2
• Add norepinephrine only if systolic BP falls below 80 mmHg to maintain life and tissue perfusion 2
• Premature vasopressor use may worsen organ perfusion through excessive vasoconstriction 2
• Consider low-dose arginine vasopressin to decrease blood product requirements in severe hemorrhagic shock 2

Orthostatic Hypotension (Chronic, Non-Acute)

Non-pharmacologic measures first, then medication if inadequate response:

• First-line pharmacologic: Fludrocortisone (mineralocorticoid for volume expansion) 6, 7
• Second-line: Midodrine (alpha-1 agonist vasopressor) for symptomatic orthostatic hypotension when lives are considerably impaired despite standard care 8, 6, 7
• Third-line: Pyridostigmine 6
• Goal is symptom relief and fall prevention, not a specific blood pressure target 7

Critical Monitoring Requirements

All patients on vasopressors require:

• Arterial catheter placement as soon as practical for continuous blood pressure monitoring 1, 4
• Continuous ECG, oxygen saturation, and urine output monitoring 5, 4
• Serial lactate levels and assessment of peripheral perfusion (skin perfusion, mental status) 5, 4, 2
• Supplemental oxygen to maintain saturation >94% 5, 4

Common Pitfalls to Avoid

• Never use vasopressors as substitute for adequate fluid resuscitation in hypovolemic states—this leads to excessive vasoconstriction and organ ischemia 2
• Never use dopamine for renal protection—it provides no benefit and increases arrhythmia risk 1, 2
• Avoid supine hypertension with midodrine by having patients take last dose 3-4 hours before bedtime and sleep with head of bed elevated 8
• Do not use vasopressin as initial monotherapy—only add to norepinephrine 1, 2
• In trauma, do not aggressively fluid resuscitate to normal blood pressure before bleeding control—permissive hypotension (systolic 80-90 mmHg) is preferred 2

Special Considerations

Drug interactions requiring caution:

• Midodrine with other vasoconstrictors (phenylephrine, pseudoephedrine, ephedrine) increases hypertension risk 8
• Cardiac glycosides with midodrine may precipitate bradycardia or arrhythmias 8
• MAO inhibitors should be avoided with midodrine 8

Renal/hepatic impairment:

• Midodrine requires dose reduction (start at 2.5 mg) in renal impairment as desglymidodrine is renally eliminated 8
• Use midodrine cautiously in hepatic impairment due to hepatic metabolism 8