Prescribing combination of drugs that reach similar parts of the body instead of just one could be an effective way of combating pathogens such as viruses or bacteria. Not all drugs can reach all parts of the body, a situation known as "imperfect drug penetration".
Researchers found that when there is a "pocket" of the body where only one drug is present, such as the brain or the digestive system, a pathogen can quickly develop resistance to one drug at a time.
"If there is a space where there is only one drug, that is the place where the pathogen can start its escape," said co-author of the study Pleuni Pennings, Assistant Professor of biology, San Francisco State University. "Once it no longer has the first drug to deal with, it is very easy for it to quickly become resistant to a second drug," Pennings said.
Because pathogens can quickly develop resistance to a single drug, providers often prescribe multiple drugs to increase their effectiveness.
The results of the study suggest that, when doing so, doctors should carefully consider which parts of the body each drug will reach.