Cephalexin in lower respiratory tract infections.

Cephalexin has had 12 years of extensive clinical usage in the management of respiratory tract and other infections. It is reliably absorbed from the gastrointestinal tract and reaches therapeutic levels in serum and tissues. Toxicity and adverse side effects are minimal. The antimicrobial spectrum includes a majority of the pathogens usually associated with community-acquired lower respiratory tract infections with the significant exception of Haemophilus influenzae. Resistance of H. influenzae strains reduces the uses of cephalexin in the paediatric population and may limit its effectiveness in some patients with acute exacerbations of chronic bronchitis. In contrast, it is inordinately effective in managing most adult patients with lower respiratory tract infections, either as a primary agent, as a substitute for penicillins or other antimicrobial agents in patients unable to receive these, or for continuation of therapy in individuals who no longer require parenteral compounds. As with other cephalosporins, caution should be exercised to exclude meningitis when treating patients with respiratory tract infections since the majority of these compounds, including cephalexin, produce little or no cerebrospinal fluid levels.