Final answer:
Tetracyclines can be used to treat both chlamydia, syphilis, and gonorrhea (STD) and acne.
Step-by-step explanation:
Tetracyclines can be used to treat both chlamydia, syphilis, and gonorrhea (STD) and acne.
For Chlamydia, the recommended drugs are azithromycin or doxycycline. Erythromycin, levofloxacin, and ofloxacin are alternative options.
For acne, tetracyclines like doxycycline are commonly used.