The use of more than one drug for the treatment of infectious diseases is a controversial issue. Combination therapy is widely used empirically in life-threatening infections, when more than one antimicrobial is preferred if a single one is not expected to have a spectrum broad enough to cover all potential pathogens. Examples include some types of pneumonia, sepsis, meningitis, and endocarditis.

When the microorganism responsible for the infection is already known, the combination of two antimicrobials may be justified because more than one drug may offer a better guarantee of cure, a more rapid defervescence, or less toxicity than a single one.<sup>249 Rybak M.J., McGrath B.J. Combination antimicrobial therapy for bacterial infections: Guidelines for the clinician Drugs 1996 ;  52 : 390-405  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Other reasons for using combined therapy may be the low intrinsic activity of a single drug, the synergistic action of the combination against a specific pathogen, the prevention of resistance emergence, or the existence of a polymicrobial infection not treatable with a single drug.<sup>255 Sanders C.V., Aldridge K.E. Antimicrobial therapy of anaerobic infections, 1991 Pharmacotherapy 1991 ;  11 (pt 2) : 72S-79S

Cliccare qui per andare alla sezione Riferimenti, 256 Sanders C.V., Aldridge K.E. Current antimicrobial therapy of anaerobic infections Eur J Clin Microbiol Infect Dis 1992 ;  11 : 999-1011  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> New agents, such as the broad-spectrum β-lactam/β-lactamase inhibitor compounds or the carbapenems, allow the use of a single agent in many of these situations. Selection of agents should depend on local susceptibility patterns, clinical experience, site of infection, potential toxicities, and cost.<sup>249 Rybak M.J., McGrath B.J. Combination antimicrobial therapy for bacterial infections: Guidelines for the clinician Drugs 1996 ;  52 : 390-405  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup>

The use of combination therapy must be balanced against its potential disadvantages, such as antagonism, increased incidence of adverse effects, superinfection, and increased cost.<sup>249 Rybak M.J., McGrath B.J. Combination antimicrobial therapy for bacterial infections: Guidelines for the clinician Drugs 1996 ;  52 : 390-405  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> This article examines evidence-based science where available and where this is not possible, practical advice on the treatment of bacterial infections is offered.