Cipro can also cause bone problems in kids. And pregnant women can't take it, since the baby's bones are affected with all three.
All antibiotics can make a woman on birth control pills ovulate. Use alternate or additional antibiotics.
Pregnant women shouldn't use doxycycline after 4 months. The teeth and bones of the baby might be affected. Cipro isn't approved at all for pregnancy. In the studies, young animals had bone marrow problems. Pregnant women, or those who might be, should have a long talk with their OB's before starting any medicine.
If the doxycycline is in your stomach at the same time as calcium or iron, the two bind together, and you don't get enough of the antibiotic absorbed. So separate them by a few hours.
I've also seen some interesting photosensitivity (sunburn) with doxycycline. So avoid sun.
(I hate interesting.)