Cpnhelp.org - Chlamydia Pneumoniae Treatment

Yes - many antibioticsii can be both bacteriocidal or bacteriostatic depending on the dosage.  They are generally classified as 'cidal or 'static depending on their antimicrobial activity against a broad number of pathogens at an average "safe" dose. 

Quinolones for example are generally categorized as 'cidal because they are bacteriocidal against a broad number of pathogens at a "standard" dosage.

It's also true that antibiotics can be 'cidal or 'static depending on the pathogen at the same dose.

For example -

Antibiotic XYZ 100mg BID vs Pathogen A = 'static response

Antibiotic XYZ 100mg BID vs Pathogen B = 'cidal response

No food, yes food, amount and type of food plus concommitant medications can also influence the antibiotics "kill" ability by effecting CMax/peak concentrations/kill levels. 

No antibiotic is generally considered to be 100% efficacious against a pathogen in 100% of all people.  Other body and genetic composition issues come into play.

Not to even consider "first pass" metabolites of drugs that are formed as the parent/orginal compound undergoes first pass metabolism thru the liver.  Often the metabolites of drugs can be even more active than the parent compound.

Also - with a drug such as say clarithromycin - 250mg BID is effective for a number of pathogens in the throat- pharyngitis or lungs - pneumoniae, etc... it however takes 500mg BID to penetrate well into the sinus tissues. 

Let's look at the macrolides as an example.  The macrolides are believed to work via binding at the 50s ribosomal unit interfering with protein synthesis. 

But each macrolide compound is chemically different - substitute a ring or molecule here or there.  This can in part account for varying degrees of efficacy with the same bacteria - different strains or even different body tissue locations.

For example - clarithromycin is only one single molecule different than erythromycin.  A single attached chemcial ring.  Otherwise the chemical structure of clarithromycin and erythromycin is identical. 

Yet that single molecule allows clarithromycin to be generally better tolerated and to have adequate Hflu and other pathogen activity than erythromycin.  Amazing the diff in one single chemical molecule in the composition of a drug.

Perhaps check out and really read this one single antibiotic PI to truly understand the complexity of the issues http://www.rxabbott.com/pdf/biapi.pdf

As a purely personal opinion, I am coming to the school of thought of antibiotic rotation within class - about every 90 to 180 days or until die off reactions diminish or until plateau of improvements is reached. 

A plausible strategy for antibiotic rotation might be

Use Roxyithromycin 150mg BID until tolerated maybe 2 to 4 weeks.  Then bump to 300mg BID.    Take about 90 to 180 days.  You can even test out efficacy by going to 300mg TID for a couple of weeks to test reaction.

Next - use clarithromycin 250mg BID until tolerated. maybe 2 to 6 weeks  Then bump to 500mg BID.  Take about 90 days to 180. You can even go to 1 gram BID.

Next use azithromycin 250mg QD until tolerated.  Then bump to 500 mg QD.  Take about 90 days to 180 days. Watch closely for tinnitis at 500mg QD.

Same could be said of tetracycline class.  Each agent in the same class of drug be it cephalosporins, macrolides, quinolones, tetracyclines, etc... will have varying degrees of efficacy on the same pathogen and will even vary in different patient populations. 

Generally, you might find that,  say for H. influenza induced bronchitis, you might find an efficacy rate of 92% for macrolide A, 94% for macrolide B and 90% for macrolide C, etc... Nothing statistically significant.  You then might consider tissue and serum levels which can quiet frankly vary widely between antibiotics in the same class. 

 In every day garden variety infectionsii, it generally doesn't matter whether you use Omnicef or Ceftin or Ceclor etc...  On the other hand, in long term antibiotic treatment if very likely may make a difference.

Also - there are no clear cut dosing equivalent studies of which I am aware.  This again is why I say, start with the lower dose for a few days, when tolerated, scour with the higher dose of the drug and then rotate. 

As I grow more and more to understand who in the lyme treating MD community are having what appears to be the very best results - this the strategy they seem to employ. 

Rotate antibiotics 2 to 4 times per year, start with lower doses and then bump to higher doses, when tolerated, move on to next agent and repeat.  Logically and with what I know of drugs - this makes sense to me.

This also makes sense to me sense as very rarely are you treating one single bacterial infection.

There are no clear cut dosing equivalent studies that I am aware within classes of antibiotics.  Pharmaceutical manufactures will rarely do head to head clinical comparisons between agents.  They might for example compare a new agent against ampicillin or amoxicillinii or erythromycin but you aren't likely to see many head to head clinical trials of Rulid, Biaxin and Zithromax.  There's a reason for that but I won't go into it here.

Attached is a review of macrolides from Marne Gaynor (a well known macrolide guru).  This is one of the most excellent reviews of the differences in macrolides, mechanisms of actions, mechanisms of resistance.  If you dig science, I highly recommend this article. LINK

As a disclaimer - I am not a doctor - all of the above is just my own personal opinion.

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Daisy - Husband on CAPii 5/07.  Roxithromycin, Rifampin, Bactrim DS, Tindamax 6-23, Tetracycline 7-3, azithromycin, doxyii, minocycline, diflucan, mepron, prednisone