Doxycycline is an antibiotic used in this study to prevent certain sexually transmitted infections after a potential exposure.

Gonorrhoea – This is a bacterial infection that primarily affects the mucous membranes of the reproductive tract. It is commonly spread through sexual contact. The infection can cause inflammation and discharge in the genital area. In some cases, it may also affect the throat or rectum. If left unchecked, the infection can spread further into the reproductive organs.

Chlamydia – This infection is caused by a specific type of bacteria that targets the reproductive system. It is typically transmitted through sexual activity. Many individuals do not show any obvious signs of the infection initially. As it progresses, it can cause irritation and discharge in the genital tract. The bacteria can also infect other parts of the body like the rectum or throat.

Syphilis – This is a bacterial infection that progresses through several distinct stages. It often begins with a small, painless sore at the site where the bacteria entered the body. Following this initial stage, the infection can move into a period where rashes appear on different parts of the body. If it continues to advance, the bacteria can spread to internal organs and tissues. The progression is typically slow and can affect various systems in the body over time.