What does RF stand for?

Rifampicin

Rifampicin, also known as rifampin, is an antibiotic used to treat several types of bacterial infections. This includes tuberculosis, leprosy, and Legionnaire's disease. It is almost always used along with other antibiotics, except when given to prevent Haemophilus influenzae type b and meningococcal disease in people who have been exposed to those bacteria.