The effect of common pharmacologic agents on pulmonary antibacterial defenses: implications for the geriatric patient

Clinical and laboratory observations have raised the possibility that common pharmacologic agents disrupt lung host defense and predispose to bacterial infection of the lower respiratory tract. Epidemiologic data suggest that the potential for an impairment in pulmonary antibacterial mechanisms is greatest among individuals of advanced age. However, lung antimicrobial systems are extremely complex, and patients with pulmonary infections characteristically have a variety of predisposing conditions. Thus, it remains very difficult to assess the relative impact of drug-related derangements on lung antimicrobial systems. Indeed, it is likely that multiple intrinsic and extrinsic factors contribute to the evolution of most bacterial pneumonias. Thus, while medications may not represent major risk factors, they may act in an additive or synergistic manner with other predisposing conditions, such as age-associated changes in immunologic activity and underlying disease, to enhance susceptibility to infectious illnesses of the lung. Clearly, substantial clinical and laboratory study will be required in order to define the role that common pharmacologic agents play in predisposing to bacterial infection of the lower respiratory tract.