Doxycycline may cause diarrhea.
Doxycycline is highly lipophilic, so it can easily enter cells, meaning the drug is easily absorbed after oral administration and has a large volume of distribution
In Canada, in 2004, doxycycline was considered a first-line treatment for chlamydia and non-gonococcal urethritis and with cefixime for uncomplicated gonorrhea

