Ted Rosenberg, Rory Lattimer, Patrick Montgomery, Christian Wiens, Liran Levy

The association between interstitial lung disease (ILD) and selective serotonin reuptake inhibitors and serotonin norepinephrine reuptake inhibitors (SSRI/SNRI) has been previously described in published case reports. However, its prevalence may be more common than expected. We examined the association between SSRI/SNRI usage and presence of ILD and or bronchiectasis (ILD/B) in an elderly population. We conducted a retrospective case series and case-control study involving all 296 eligible elderly patients in one primary care geriatric practice in Victoria, BC, Canada. Cases required the presence of ILD/B on computed tomography (CT) or chest X-ray (CXR). Cases were excluded if they had other causes for ILD/B on CXR or CT such as exposure to known pneumotoxic drugs, metastatic cancer, rheumatoid lung disease, sarcoidosis, previous pulmonary tuberculosis, or pneumoconiosis. Data were abstracted from the patients' medical record. The exposure variable was standardized cumulative person-month (p-m) dose of SSRI/SNRI. The study was approved by the Clinical Research Ethics Board of University of British Columbia with a waiver of informed consent. A total of 12 cases and 273 controls were identified. Their mean ages were 89.0 and 88.7 years, respectively (p=0.862). A total of 10/12 cases and 99/273 controls were exposed to SSRI/SNRI. The odds ratio was 8.79, 95% confidence interval 2.40-32.23 (p=0.001). The median p-m exposure to SSRI/SNRI was 110.0 months for cases and 29.5 for controls (p=0.003). SSRIs and SNRIs were significantly associated with the risk of ILD/B in this elderly population. Because of their widespread usage, further studies should be done to validate these findings. Prescribers should cautiously monitor patients for development of insidious pulmonary symptoms when these drugs are used.