Give an example on a guideline of prescribing antibiotics.

At first an STI (sexually transmitted infection) patient was given 1 injection of Ceftriaxone (Cephalosporin) + 1g of azithromycin for once but in 2021 a new recommendation reclaims that in STI we give the injection of ceftriaxone but now we give with it Doxycycline 100mg twice a day for 7 days.