Background: Central Nervous System (CNS) depressants like antipsychotics, opioids,
benzodiazepines and zolpidem are frequently used by patients of a wide range of ages. Uncertainty
remains about their effect in very old adults (>80 years old) and their potential for pharmacodynamic
and pharmacokinetic drug-drug interactions in this population.
Objective: To assess if the use of CNS depressants is associated with a higher risk of hospitalization
due to community-acquired pneumonia (CAP) in very old patients.
Methods: In this prospective study, 362 patients over 80 years of age who had been consequently
admitted to the general ward of a teaching hospital were examined. Each patient was assessed, by
our pharmacovigilance team within 24 hours of admission, to identify outpatient medication use and
potential drug-drug interactions.
Results: The overall use of CNS depressants as a group was not associated with a higher risk of
admission due to CAP in very old patients (55% vs. 49%; OR=1.28 [0.76-2.16], p=0.34). However,
the use of antipsychotics was associated with a higher rate of admissions due to CAP in this population
(OR=1.98 [1.10-3.57], p=0.02). No association was seen between opioids (p=0.27), zolpidem
(p=0.83), or benzodiazepines (p=0.15) and the rate of admissions due to CAP in these patients.
Moreover, pharmacodynamic or pharmacokinetic interactions leading to CNS depression were
equally found in patients admitted for CAP and those admitted for other reasons.
Conclusion: The use of antipsychotics in very old adults was associated with an increased risk of
hospital admission due to CAP. This suggests that the use of these medications in this population
should be done with caution. No association was observed with opioids, benzodiazepines and
zolpidem with the latter outcome.