Can lorazepam (Ativan) cause hypotension, especially in elderly patients or those with a history of hypotension?

Can Lorazepam Cause Hypotension?

Yes, lorazepam can cause hypotension, particularly respiratory depression and systemic hypotension when administered with other cardiopulmonary depressants like opioids, and this risk is significantly elevated in elderly patients, those with baseline cardiovascular instability, and when given intravenously. 1

Mechanism and Risk Profile

Lorazepam causes hypotension through benzodiazepine-mediated cardiovascular depression, which is amplified by:

• Combination with other sedatives: Benzodiazepine-induced cardiopulmonary instability is more likely when administered with opioids or other cardiopulmonary depressants 1
• Baseline instability: Critically ill patients with respiratory insufficiency and/or cardiovascular instability are at highest risk 1
• Route of administration: Intravenous lorazepam carries greater hypotensive risk than oral formulations 1

Elderly Patients: Heightened Vulnerability

Elderly patients face substantially increased risk of hypotension from lorazepam due to age-related pharmacokinetic and pharmacodynamic changes. 1, 2

Key considerations in older adults:

• Enhanced sensitivity: Elderly patients are significantly more sensitive to benzodiazepine sedative effects, with decreased clearance requiring dose reduction 1, 2
• Orthostatic hypotension: Lorazepam can induce or worsen orthostatic hypotension, contributing to falls and syncope in 10-30% of elderly patients 3, 4
• Dose adjustments mandatory: Maximum doses should not exceed 2 mg/24 hours in elderly or debilitated patients, with initial dosing at 0.25-0.5 mg 2
• Constitutional low blood pressure: A recent case report demonstrates that patients with baseline low blood pressure (90-95/50-55 mmHg) can develop dose-related orthostatic symptoms and hypotension even with standard lorazepam dosing 5

Clinical Manifestations

Hypotension from lorazepam overdose or excessive dosing presents as: 6

• Cardiovascular depression
• Hypotonia and ataxia
• Respiratory depression
• Progression to hypnotic state or coma in severe cases

High-Risk Scenarios

Avoid or use extreme caution with lorazepam in:

• Patients with pre-existing hypotension or cardiovascular instability 1
• Elderly patients, particularly those over 75 years 1, 2
• Concurrent use with other CNS/cardiovascular depressants (opioids, antipsychotics, antihypertensives) 1
• Patients with hepatic or renal dysfunction (prolonged elimination increases hypotensive duration) 2
• Dehydrated patients (orthostatic hypotension risk amplified) 5

Practical Safeguards

To minimize hypotension risk:

• Start low in elderly: Use 0.25-0.5 mg doses, maximum 2 mg/24 hours 2
• Monitor vital signs: Check blood pressure before and after administration, particularly with IV dosing 1
• Assess orthostatic changes: Measure both supine and standing blood pressure with heart rate in at-risk patients 5
• Avoid polypharmacy: Review and minimize concurrent use of antihypertensives, alpha-blockers, calcium channel blockers, and other vasodilators 1, 4
• Hydration status: Ensure adequate hydration, particularly in elderly patients where dehydration compounds orthostatic effects 5
• Propylene glycol toxicity: With IV formulations, total daily doses as low as 1 mg/kg can cause metabolic acidosis and acute kidney injury from propylene glycol accumulation 2

Notable Exception

Interestingly, one study of high-dose IV lorazepam (0.3-9 mg/hr) for refractory status epilepticus found that lorazepam did not cause hypotension in this specific context 7. However, this finding should not be generalized to other clinical scenarios, particularly given the overwhelming evidence of hypotensive risk in standard use.

Common Pitfall

The most dangerous prescribing error is continuing lorazepam in elderly patients who develop hypotension without dose reduction or discontinuation. 8 Studies demonstrate that older people often remain on medications despite being hypotensive, resulting in increased mortality and hospital admission. Always reassess the need for lorazepam when blood pressure drops below 120 mmHg systolic in elderly patients. 8