Many common infections in human are caused by single cell organisms, called bacteria. Bacteria can grow and multiply, infecting different parts of the body. Medicines that prevent and treat these infections are called antibiotics. Ciprofloxacin is an antibiotic that stops multiplication of bacteria by inhibiting the reproduction and repair of their genetic material (DNA).

Ciprofloxacin should be taken exactly as directed. It may be taken with or without food. Ciprofloxacin is partially metabolized by the liver and excreted by the kidney. Dosages require adjustment in patients with severely abnormal liver or kidney function. Antacids block the absorption of ciprofloxacin and they should not be taken together. For uncomplicated urinary tract infections, Cipro XR can be given twice daily for three days while Proquin XR can be given once daily for three days.

Most common side-effects include nausea, vomiting, diarrhea, abdominal pain, rash, headache, and restlessness. Allergic reactions such as hives and anaphylaxis (shock) have been described as rare side-effects.

Ciprofloxacin should be used with caution in patients with central nervous system diseases such as seizures, because rare seizures have been reported in patients receiving this medication. Ciprofloxacin should be avoided in children and adolescents below 18 years of age, as safe use in these patients have not been established. Patients taking ciprofloxacin can develop sensitivity of the skin to direct sunlight.
Ciprofloxacin administered together with theophylline can lead to elevated blood levels of theophylline. Theophylline is used to open airways in the treatment of asthma. Toxic levels of theophylline can lead to seizures, and disturbances in heart rhythm. If concurrent use of ciprofloxacin and theophylline cannot be avoided, frequent blood tests to monitor theophylline blood levels are performed.
Many antibiotics, including ciprofloxacin, can alter the normal bacteria in the colon and encourage overgrowth of bacteria responsible for the development of inflammation of the colon (pseudomembranous colitis). Pseudomembranous colitis can cause fever, abdominal pain, diarrhea, and sometimes even shock. Ciprofloxacin can enhance the action of the anticoagulant warfarin (Coumadin), and increase the risk of bleeding.

Ciprofloxacin is used to treat infections of the skin, lungs, airways, bones, and joints caused by susceptible bacteria. Ciprofloxacin is effective in treating infectious diarrheas caused by E. coli, campylobacter jejuni, and shigella bacteria. Ciprofloxacin is also frequently used to treat urinary infections caused by bacteria such as E. coli.