Food, calcium, magnesium, antacids and some drugs reduce absorption, and alcohol, phenytoin, Dilantin, or barbiturates reduce blood half-life or suppress the immune system.
Minocycline (Minocin) can be substituted, and for some illnesses (RA) it is preferred because it penetrates tissues better (same dose/day).
For GWI/CFS/FMS/RA use, the recommended oral dose is 200-300 mg/day (2-3X 100 mg capsules, 2 in the morning) for 6 months. After 6 months, 6 wk cycles are suggested.
Initially, doxycycline can exacerbate chronic signs and symptoms (Herxheimer reactions or adverse responses, such as transient fever, skin, gut discomfort, etc.) but these are usually reduced within a few wks (see first section). Patients usually start feeling better with alleviation of major signs and symptoms within 12 wks, but in some patients’ major symptoms are not alleviated until after 12 wks.
Severe reactions or prior damage to the gastrointestinal track may require i.v. administration of 100-150 mg/day (rapid i.v. administration must be avoided) for 2-3 wks, then the remainder of the course should be oral (to avoid thrombophlebitis and other complications that can occur with prolonged i.v. therapy).
Some patients react to the starch filler in the capsules and must use Doryx, a granular form of pure doxycycline.
Virtually all patients relapse (show the same major signs and symptoms) if they stop therapy before 6 months. In a pilot study, ~85% relapsed after 12 weeks of therapy, so the first 6 months without a break is recommended.
Doxycycline has been used successfully in addition to other antibiotics in situations where either antibiotic alone had minimal effects (ie, doxycycline plus ciprofloxacin or doxycycline plus azithromycin).
Doxycycline and minocycline are primarily bacteriostatic and effective against the following organisms: gram-negative bacteria (N. gonorrhoeae, Haemophilus influenzae, Shigella species, Yersinia pestis, Brucella species, Vibrio cholera); gram-positive bacteria (Streptococcus pneumoniae, Streptococcus pyogenes); mycoplasmas (Mycoplasma pneumoniae, Mycoplasma fermentans inc. incognitis strain, Mycoplasma penetrans); others (Bacillus anthracis anthrax, Clostridium species, Chlamydia species, Actinomyces species, Entamoeba species, Treponema pallidum syphilis, Plasmodium falciparum malaria, and Borrelia Lyme species).
Precautions: Avoid direct sunlight and drink fluids liberally, especially with oral capsules. Doxycycline or minocycline therapy may result in overgrowth of fungi or yeast and nonsensitive microorganisms (see Considerations, first page).
Patients on anticoagulants may require lower anticoagulant doses. Use during pregnancy or in children under 8 years is not recommended, in the latter case due to tooth discoloration, but lower doses of doxycycline have proven to be very effective in children with GWI/CFS (weight 100 lbs or less, 1-2 mg/lb divided into two doses; weight over 100 lbs use adult dose).
Patients with impaired kidney function should not take doxycycline, and the following drugs should not be taken with doxycycline: methoxyflurane Penthrane, carbamazepine Tegretol, digoxin or diuretics. Other drugs can effect uptake or immune systems (see above).
For complicating bacterial infections, 2 wks Augmentin (3X 500 mg/day) can be taken in between courses of antibiotics. For fungal and yeast complications, please see the instructions above.
Adverse Reactions: In a few patients doxycycline causes gastrointestinal irritation, anorexia, vomiting, nausea, diarrhea, rashes, mouth dryness, hoarseness, and in rare cases hypersensitivity reactions, hemolytic anemia, skin hyper-sensitivity and reduced white blood cell counts.
In general, doxycycline is considered a very safe drug, in that there are few adverse reactions reported in the literature."
Cheers ~~ ICU