Synergy against fungal pathogens: working together is better than working alone.

Opportunistic fungi are the most important pathogens in modern world. They are responsible for severe infections in majority of immunocompromised patients. These microorganisms are commonly present in our environment which is natural reservoir of new, resistant species. For this reason mycoses are mainly chronic or long-lasting diseases. Our arsenal of antifungal drugs is growing but still insufficient for emerging resistant pathogens. An alternative for novel chemical entity drugs is the multidrug approach. This exploiting the drugs being currently on market applying simultaneously for better efficacy or to eradicate resistance. Synergy is the term that describes the phenomenon of increased potency of two or more drugs administered in combination. In the last decades it gains more interest and numbers of synergy claimed reports is growing exponentially. However these have rather low impact on clinical trials or practical use of antimycotics. In present review we wish to discuss current status of synergy between antifungal drugs. Both theoretical point of view and practical applicability in clinical terms are covered. There are serious differences between the assumptions, methods and interpretations of the results and sometimes even obvious mistakes in the procedure that was applied or in the outcomes discussed. On the other hands the specificity of fungal infections introduce dozens of factors affecting the observed results. Shift form in vitro studies to clinical trials reveals further difficulties. Hopefully multi-drug approach seems to be effective even if no strong synergy is displayed.