200 mgs of doxy will only be bacteriostatic - keeping the bacteria from reproducing- not bactericidal - killing the bacteria. It takes 400 to 600 mgs of Doxy a day in order to actually kill the bacteria.
www.news-medical.net/news/2004/10/21/5741.aspx From "Advanced Topics in Lyme Disease" by Joseph Burrascano (which can be found in our "New to Lyme?" thread):
"There are four types of antibiotics in general use for Bb treatment. The TETRACYCLINES, including doxycycline and minocycline, are bacteriostatic unless given in high doses. If high blood levels are not attained, treatment failures in early and late disease are common. However, these high doses can be difficult to tolerate.
For example, doxycycline can be very effective but only if adequate blood levels are achieved either by high oral doses (300 to 600 mg daily) or by parenteral administration. Kill kinetics indicate that a large spike in blood and tissue levels is more effective than sustained levels, which is why with doxycycline, oral doses of 200 mg bid (twice a day) is more effective than 100 mg qid (4 times a day). Likewise, this is why IV doses of 400 mg once a day is more effective than any oral regimen."
Now this doesn't explain that some doctors will want you to slowly build up to the higher dosage, especially if you (or your child) has been quite ill or has a long-standing infection in order to prevent serious herxing.
Hbd Forgive me, but 3 weeks of abx at 200 mgs a day may have you feeling well at the end, but it won't kill off the bacteria no matter how little time you have had the infection. These are incredibly complex infections - part of the reason why there is so little research on them - the other part is because of the stupid controversy.
Even if you were taking 600 mgs of Doxy a day, 3 weeks will only knock the infection down, leaving enough of the bacteria to come roaring back out once you are under enough physical stress - even something as simple as having to move can bring out Lyme that hasn't been treated thoroughly. It needs to be put into
full remission.
Doc's that aren't specifically educated by ILADS often get things wrong. Please do your research to save yourself from chronic Lyme which is much, much harder to put into remission.