Mental status, the intensive care unit, and cimetidine

Area of Science:

• Pharmacology
• Critical Care Medicine
• Neuroscience

Background:

• Cimetidine is a commonly used medication.
• Altered mental status (MS) is a significant concern in intensive care settings.
• The relationship between cimetidine and MS, particularly in patients with organ dysfunction, requires further investigation.

Purpose of the Study:

• To investigate the association between cimetidine treatment and the occurrence of altered mental status (MS) in surgical intensive care unit (SICU) patients.
• To determine if the degree of renal or hepatic dysfunction influences the incidence or severity of cimetidine-associated MS.
• To characterize the nature of MS changes and their reversibility.

Main Methods:

• A blinded, prospective study design.
• Inclusion of 217 surgical intensive care patients.
• Stratification of patients based on the presence and severity of renal and/or hepatic dysfunction.
• Comparison of cimetidine-treated patients with a non-cimetidine control group.
• Monitoring of mental status changes and relevant clinical data.

Main Results:

• A statistically significant correlation was found between cimetidine treatment and altered mental status (p < 0.0001).
• The incidence of MS changes ranged from 33% in patients without organ dysfunction to 80% in those with both renal and hepatic impairment.
• The magnitude and type of MS changes were influenced by the degree of underlying disease and serum drug concentrations.
• All observed MS changes resolved within 24–36 hours after cimetidine discontinuation.

Conclusions:

• Cimetidine treatment is associated with a significant risk of altered mental status in SICU patients.
• The risk and severity of cimetidine-induced MS are amplified in patients with coexisting renal and hepatic dysfunction.
• Both drug dosage and the patient's underlying disease state are critical determinants of cimetidine-associated neurological side effects.