Na, H2O, and K. Thus, the drug has a diuretic effect and reduces fluid load. This is not so much of a problem with either minocycline or doxycycline. Iron binds to tetracycline. If both drugs are required, give them 2-3 hours apart. Birth control pills.
Interaction here applies to all antibiotics and wonem of child-bearing age.
They are excreted in the bile to the gut. Bugs in the gut hydrolyze the conjugates and free the parent steroid compound which is then reabsorbed. This keeps the blood level up. With antibiotics, gut flora is suppressed, therefore diminishing the availability of hydrolytic enzumes to regenerate the parent steroid. The plasma concentrations of the contraceptive agent then decreases and is cleared more rapidly from the blood stream.