Ciprofloxacin treats anthrax and plague, yet guidelines often keep it in reserve
Bayer's ciprofloxacin can tackle infections from anthrax and bubonic plague to hospital-acquired urinary infections, and the World Health Organization calls it critically important for human medicine. That very importance is why many guidelines now tell doctors to try older, narrower antibiotics first for milder cases.
Patented in 1980 and launched by Bayer in 1987, ciprofloxacin is a second-generation fluoroquinolone that generally kills bacteria rather than merely halting their growth. It comes as tablets, eye and ear drops and an intravenous infusion, and it is a cheap generic on the WHO's essential medicines list. In 2023 it ranked 155th among American prescriptions, with more than 3 million issued.
Its strength lies against Gram-negative bacteria such as Pseudomonas aeruginosa. The Infectious Diseases Society of America lists it, paired with metronidazole, among first-line options for abdominal infections picked up in the community, and it features in guidance for kidney infections, prostatitis, some forms of endocarditis and infected joint replacements.
Its limits are just as telling. For ordinary urinary infections, the same society suggests saving fluoroquinolones for cases where narrower drugs like nitrofurantoin are expected to fail, to slow the spread of resistance. It is weak against Streptococcus pneumoniae, so most guidelines prefer so-called respiratory quinolones such as levofloxacin for pneumonia, and it is not a first choice for sinusitis. Although still licensed for gonorrhoea in many countries, that use is widely seen as outdated because the bacterium has grown resistant.
Nausea, vomiting and diarrhoea are the usual side effects, but rarer ones include tendon rupture, hallucinations and nerve damage, and it can worsen weakness in people with myasthenia gravis. Overall side-effect rates look higher than with cephalosporins and lower than with clindamycin. Animal studies raised concerns about pregnancy; an expert review judged therapeutic doses unlikely to cause major birth defects while stressing that the data cannot rule risk out. It appears compatible with breastfeeding.
Source: Ciprofloxacin
