What is the management for an elderly patient who accidentally took an overdose of losartan (angiotensin II receptor antagonist)?

Management of Losartan Overdose in Elderly Patient

The immediate management for an elderly patient who accidentally took more than 5 tablets of losartan includes supportive care with close monitoring of blood pressure and heart rate, as the most likely manifestation of overdose would be hypotension and tachycardia. 1

Initial Assessment and Monitoring

• Obtain vital signs immediately with special attention to:

  • Blood pressure (sitting and standing to assess for orthostatic hypotension)
  • Heart rate (monitor for tachycardia or bradycardia)
  • Respiratory rate
  • Level of consciousness

• Establish intravenous access for potential fluid administration

• Monitor the following parameters:

  • Continuous cardiac monitoring for arrhythmias
  • Urine output (to assess renal perfusion)
  • Serum electrolytes, particularly potassium
  • Renal function tests (BUN, creatinine)

Treatment Protocol

1. For symptomatic hypotension:

   • Place patient in Trendelenburg position
   • Administer IV fluids (normal saline bolus)
   • If hypotension persists despite fluid resuscitation, consider vasopressors

2. For bradycardia (which may occur from parasympathetic stimulation):

   • Atropine if clinically significant
   • Consider temporary pacing for severe cases

3. Important considerations:

   • Hemodialysis is not effective for removing losartan or its active metabolite 1
   • Monitor for at least 6-8 hours as the active metabolite (E-3174) has a longer half-life (6-9 hours) than losartan itself 2

Special Considerations for Elderly Patients

• Elderly patients are more susceptible to hypotensive effects due to:

  • Age-related changes in baroreceptor sensitivity
  • Reduced renal function
  • Potential volume depletion (especially if on diuretics)
  • Polypharmacy with potential drug interactions

• Monitor more closely for orthostatic hypotension as elderly patients have increased risk of falls 3

• Pay particular attention to renal function, as acute kidney injury can occur, especially in patients with:

  • Pre-existing renal impairment
  • Concomitant use of diuretics
  • Undiagnosed renal artery stenosis 4

Follow-up Care

• Once stabilized, reassess the patient's regular antihypertensive regimen
• Consider medication reconciliation and pill organizers to prevent future overdoses
• Educate the patient and caregivers about proper medication administration
• Schedule follow-up within 1-2 weeks to reassess blood pressure control and renal function

Potential Complications to Monitor

• Acute kidney injury, especially in patients with underlying renal disease
• Hyperkalemia (particularly if patient has renal impairment)
• Hyponatremia (rare but reported with losartan) 5
• Prolonged hypotension leading to end-organ damage

Prevention of Future Events

• Simplify medication regimen when possible
• Consider blister packs or other compliance aids
• Involve caregivers in medication management
• Regular follow-up to assess medication understanding and adherence

Remember that while losartan overdose is generally well-tolerated compared to some other antihypertensives, elderly patients are at higher risk for adverse effects and require close monitoring and supportive care.