Avoid prolonged exposure to sunlight. Ciprofloxacin may increase the sensitivity of the skin to sunlight, and a sunburn may result. If sun exposure is unavoidable, wear protective clothing and use a sunscreen. Call your doctor if you experience severe burning, redness, itching, rash, or swelling after exposure to the sun. Use caution when driving, operating machinery, or performing other hazardous activities. Ciprofloxacin may cause dizziness. If you experience dizziness, avoid these activities. Avoid excessive consumption of products that contain caffeine. Ciprofloxacin may increase the effects of caffeine. 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. 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 under 18 years old, as safe use in these patients have not been established. Many antibiotics, including ciprofloxacin, can alter the normal bacteria in the colon and encourage overgrowth of a bacteria, responsible for the development of inflammation of the colon (pseudomembranous colitis). Pseudomembranous colitis can cause fever, abdominal pain, diarrhea, and sometimes even shock. Patients taking ciprofloxacin can develop sensitivity of the skin to direct sunlight. Ciprofloxacin can enhance the action of the anticoagulant warfarin (Coumadin), and increase the risk of bleeding. Ciprofloxacin should be avoided in pregnancy, as safe use in these patients have not been established. Ciprofloxacin should be avoided in nursing mothers, as safe use in these patients have not been established.

The most frequent side effects include nausea, vomiting, diarrhea, abdominal pain, rash, headache, and restlessness. Rare allergic reactions have been described, such as hives and anaphylaxis (shock).

If you experience any of the following serious side effects, stop taking ciprofloxacin and seek emergency medical attention or contact your doctor immediately: an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives); seizures; confusion or hallucinations; liver damage (yellowing of the skin or eyes, nausea, abdominal pain or discomfort, unusual bleeding or bruising, severe fatigue); or muscle or joint pain; skin rash; or chest pain, chest discomfort, shortness of breath, or swelling of the legs or feet. If you experience any of the following less serious side effects, continue taking ciprofloxacin and talk to your doctor: nausea, vomiting, diarrhea; headache; dizziness or lightheadedness; drowsiness; insomnia; ringing in the ears; or increased sensitivity of the skin to sunlight. Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.