Ciprofloxacin (brand name Cipro®) is a common antibiotic prescribed to treat various types of bacterial infections. Read below to learn more about ciprofloxacin and how it can be used to treat common infections you may encounter.

What is Ciprofloxacin?

Ciprofloxacin is a versatile antibiotic available in several forms, such as oral pills, eye drops, and ear drops. It is effective against bacterial infections but not against viral or fungal infections.

In adults, ciprofloxacin is commonly used to address urinary tract infections (UTIs) and can also be prescribed for infectious diarrhea, bacterial conjunctivitis (also known as "pink eye"), and swimmer's ear. Although ciprofloxacin pills are not typically recommended for children, the drops can be used to treat pink eye and swimmer's ear in pediatric cases.

As a member of the fluoroquinolone family of antibiotics, ciprofloxacin works by inhibiting bacterial growth within the body.

What is ciprofloxacin commonly used for?

Ciprofloxacin can be used for several reasons. Some of the most common uses include the treatment of UTI, infectious diarrhea, conjunctivitis, and ear infections.

Ciprofloxacin for UTI

In adults, ciprofloxacin is commonly used for the treatment of UTIs.

UTIs can be diagnosed with simple urine tests, where doctors can look for white blood cells, bacteria, and other signs of infection in the urine.

Patients diagnosed with a UTI may be prescribed ciprofloxacin pills to take by mouth. Possible regimens include ciprofloxacin 250 mg every 12 hours. A regimen of ciprofloxacin 500 mg extended release every 24 hours is also an acceptable alternative. The treatment period typically lasts 3 days for females and 5 days for males. Due to potential side effects, ciprofloxacin is not typically used to treat UTI in children.

For those with “complicated UTIs,” IV ciprofloxacin may be administered in the hospital. “Uncomplicated” urinary tract infections are infections that are confined to the bladder, with patients typically experiencing pain with urination, increased urinary frequency and urgency, and suprapubic pain. “Complicated” UTIs have spread beyond the bladder to the kidneys, and include the symptoms listed above in addition to fever, chills and rigors, flank pain, and/or pelvic pain in men. Women who are pregnant and those with underlying kidney disease may receive special treatment regimens and should always consult with a doctor if they suspect a UTI.

Infectious diarrhea

Diarrhea has many causes, one of which is foreign bacteria entering the gastrointestinal system. The mechanism by which these bugs cause diarrhea will differ, and the type of diarrhea you have may provide clues about the culpable bug. In cases of adults with mild to moderate symptoms, infectious diarrhea typically resolves with only supportive treatment (rest, adequate hydration, and dietary changes), and without antibiotics.

In cases of severe diarrhea that do not resolve with supportive treatment, doctors may recommend a course of ciprofloxacin pills to take by mouth, which studies have shown can reduce the time from diarrhea onset to resolution.

Ciprofloxacin 500 mg is typically prescribed for 5-7 days in such cases, but the exact dose and duration depend on the type of bacteria, the severity of the symptoms, and the health history of the patient. As such, it is important to consult with a doctor if these situations arise.

Diarrhea that is not getting better, that is accompanied by cramping or vomiting, that contains blood, or that occurs in an older or immunocompromised individuals should always be evaluated by a doctor.

Conjunctivitis (“Pink eye”)

Ciprofloxacin eye drops or ointment can also be used to treat bacterial causes of conjunctivitis, also known as pink eye. (Usually only ciprofloxacin drops or ointment, and not pills, are used for this purpose.)

People who develop pink eye typically experience redness and thick discharge that is yellow, white, or green accompanied by mild itching. Typically only one eye is affected, although both eyes can be infected at the same time. Individuals may also experience their eye(s) being “stuck shut” in the morning.

Bacterial conjunctivitis is highly contagious and spread via direct contact with a patient or the discharge from their eyes. The diagnosis of pink eye is typically clinical, meaning lab tests are not required for a doctor to prescribe treatment unless the symptoms are particularly severe or long-lasting or the patient experiences a change in his or her vision.

The typical adult dose of ointment is a ½ inch ribbon to the affected eye 3 times/day for the first 2 days, followed by a ½ inch applied twice daily for the next 5 days. For eye drops, adults are typically instructed to instill 1 to 2 drops into the eye every 2 hours while awake for 2 days and 1 to 2 drops every 4 hours while awake for the next 5 days.

Otitis externa (“swimmer’s ear”)

Ciprofloxacin can also be used in an ear drop form to treat acute otitis externa, more commonly known as swimmer’s ear.

These infections are typically caused by bacteria such as Pseudomonas aeruginosa or Staphylococcus aureus and are common in pediatric patients, resulting in inflammation of the external ear canal. Individuals with a recent history of swimming or other water exposure, trauma from cleaning or scratching the ear, or use of hearing aids or earphones, may be more likely to develop an external ear infection. Patients with otitis externa typically complain of ear pain, itching, discharge, and loss of hearing. Similar to pink eye, swimmer’s ear is a clinical diagnosis, based on the patient’s recent activities and medical history; testing is typically reserved for severe cases.

Ciprofloxacin solutions intended for ear infection treatment are typically available as a 0.2% solution. The recommended dose is 0.25 mL (equal to the contents of 1 single-dose container) to be instilled into the affected ear(s) two times daily for 7 days.

Bioterrorism agents

Bacillus anthracis (“anthrax”)

Ciprofloxacin may also be prescribed for treatment against Bacillus anthracis exposure, more commonly known as “anthrax.” Sporadic cases of anthrax do naturally occur worldwide, but rarely in developed countries. However, anthrax may be used in developed countries as a means of bioterrorism.

Cutaneous anthrax is the most common manifestation of anthrax exposure and, when naturally occurring, is most commonly due to contact with infected animals or animal products. Symptoms include small itchy bumps that can progress to large black ulcers at the site of exposure with swelling of the surrounding skin. These skin manifestations may be accompanied by fever, headache, and other general symptoms.

Inhalational anthrax results when a person inhales spores of Bacillus anthracis and is the most common means of weaponizing anthrax. Early symptoms may feel like the flu, including body aches and fever, but can also include nausea, vomiting blood, and shortness of breath. After around 4-5 days, these symptoms progress rapidly to severe shortness of breath and shock. Although most cases of inhalational anthrax will progress to death, antibiotic therapy may be successful if initiated when symptoms first present.

In cases of anthrax exposure, ciprofloxacin is the agent of choice in both adults and children for antimicrobial therapy; however, it is administered in its IV form and is given alongside numerous other drugs to treat the infection.

Yersinia pestis (“plague”)

Y. pestis is transmitted by fleas and causes what is commonly referred to as “plague.” Bubonic plague is the most common manifestation of plague, which begins as a small lesion on the skin located at the site of a flea bite. This lesion may go unnoticed, but can also progress to a bump, blister, ulcer, or scab. The most recognizable symptom of bubonic plague is painful, swollen lymph nodes in the region of the body where the flea bite occurred. Patients may also experience fever, chills, headache, and other general symptoms.

Without treatment, patients can develop an overwhelming, widespread inflammatory response to the infection (sepsis) followed by death. However, prompt antibiotic therapy can improve the likelihood of recovery, and ciprofloxacin is a first-line agent. Initial therapy with IV antibiotics is typically recommended, but oral agents may be appropriate in certain circumstances.

What side effects can I expect with ciprofloxacin use?

Compared with other antibiotics, ciprofloxacin is associated with a higher number of side effects, particularly in the oral form. One of the more common side effects of ciprofloxacin is diarrhea.

Ciprofloxacin can cause tendon problems, such as tendinitis or tendon rupture, and carries a "Black Box" warning from the FDA highlighting this and other risks.

Ciprofloxacin can cause tears in blood vessels, including the aorta, which could be fatal. Ciprofloxacin is dangerous in people who are predisposed to problems with tendons and the aorta, such as people with connective tissue disease. It is also known to cause peripheral neuropathy, central nervous system effects, severe rashes (including Stevens-Johnson syndrome), lung problems (pneumonitis), liver failure, anemia, allergic reaction, heart arrhythmias (via prolongation of the QT interval), muscle and joint problems, diarrhea (including C. difficile diarrhea), and more.

This list of side effects is not exhaustive and certain side effects may be more relevant to you based on your health history. You should always check with your doctor before starting a new medication.

Can children take ciprofloxacin?

Oral ciprofloxacin is rarely given to children due to the risk of bone and joint issues. In general, oral ciprofloxacin (i.e. a pill) is not given to children under age 18 unless they suffer from a serious infection that cannot be treated with another antibiotic, or unless they have been exposed to plague or airborne anthrax.

How do I know if I need to take ciprofloxacin?

There are cases in which other classes of antibiotics may be preferred over ciprofloxacin in treating a bacterial infection listed above based on the type of bacteria involved or certain other conditions a person may have. As always, it is best to consult with your doctor if you think you have developed a bacterial infection that requires treatment with ciprofloxacin.

The information provided on this site is intended for your general knowledge only and is not a substitute for professional medical advice or treatment for specific medical conditions. You should not use this information to diagnose or treat a health problem or disease without consulting with a qualified healthcare provider. Please consult your healthcare provider with any questions or concerns you may have regarding your condition. If you think you may have a medical emergency, call your doctor, go to the emergency department, or call 911 immediately.