Doctors treating chronic Lyme disease with long-term antibiotics certainly have a lot of different approaches. Some physicians pulse antibiotics: drug A is taken for X days and held for Y days and the cycle repeats. Some doctors use antibiotics continuously. Some use a single antibiotic agent and others use multiple antibiotics. Some physicians prescribe a complex recipe: take A on Monday and Wednesday, take B on Friday and Tuesdays, Take C on Saturday, skip Sunday, but combine C and D alternate Sundays etc. Patients are left wondering, what is the best approach? Doctors base their choices on theories and clinical experience. Nobody knows the right answer. But I will share my biases.
When antibiotics are pulsed research shows that resistant forms of bacteria are more likely to develop. Combinations of antibiotics reduce the likelihood of resistance. In addition, for reasons unknown, a combination of medicine may change the resistance characteristics of a bacteria. For example, when Cipro is added to minocycline it has been observed that a heretofore minocycline resistant bacteria may become sensitive to minocin. In other words, the minocycline was unable to kill the microbe until Cipro was added to the mix.
Mathematical models and studies (although others disagree) have shown that the use of two synergistic antibiotics reduces the likelihood of the emergence of antibiotic resistant strains.
We are unable to assess the antibiotic resistance patterns of Lyme spirochetes but we know they posses the genetic wherewithal to create multi-drug resistance.
When dealing with such a notoriously difficult to treat organism. It has been found that two combined antibiotics kill more germs than either taken alone. This also applies to a strategy of alternating the two antibiotics. In other words, it is more effective to take A and B together for 30 days than to take A for 15 days and B for 15 days.
It is commonly known that drugs like Zithromax are added to Mepron to avoid the development of resistance in the treatment of Babesia. It is also commonly known that Rifampin should never be used as a single agent to prevent the quick onset of resistance to this agent.
Literature and clinical experience supports the idea of bathing tissues in a constant concentration of an antimicrobial. For example, intramuscular penicillin (ouch) works - even though the amount(milligrams) of drug delivered per injection is low because there is a steady concentration of antibiotic bathing the target tissues. A slow intravenous infusion of an antibiotic over hours has been shown in one study to work better than infusion of the same drug over a shorter period of time.
I prefer to use antibiotics in combination. I have found it works; anyway it is less confusing than some other treatment protocols. In addition to clinical experience, there is some science to support this approach.
Another concept has been suggested. And this has always made sense to me. We know that antibiotics are unable to kill all the spirochetes (or other organisms). Our goal is to get patients into remission. We think than happens because the immune system "learns" how to control the parasites. Dead bacteria released into the circulation allow the body's defenses the opportunity to become better at controlling the unwanted spirochetes. In other words, a type of self vaccination occurs when organisms are continually killed. It has been suggested that pulsing is a more effective way to accomplish this task. I do not understand this reasoning but maybe I am missing something.