Ciprofloxacin: Boxed Tendon Warning and the 500 mg UTI Course

What is ciprofloxacin used for?

Ciprofloxacin is used for bacterial infections such as urinary tract infections (UTIs), skin and soft tissue infections, respiratory tract infections, bone and joint infections, intra-abdominal infections, and infectious diarrhea. It can also be used to treat plague or anthrax after exposure.

Ciprofloxacin can also be used to prevent or treat plague in certain situations. It is not recommended for treating bronchitis or flu symptoms because these are viral infections that do not respond to antibiotics.

Ciprofloxacin 500 mg dosage for UTI

For a urinary tract infection, the usual adult dose of ciprofloxacin is 250 to 500 mg every 12 hours. The duration of treatment depends on the type and severity of the infection.

For complicated infections, longer treatment may be required. The dose may be increased up to 750 mg twice daily for more severe infections.

Ciprofloxacin side effects

The most common side effects of ciprofloxacin are nausea, diarrhea, vomiting, headache, dizziness, and rash. Serious side effects can occur with ciprofloxacin use and may include tendon rupture, peripheral neuropathy, and allergic reactions.

These reactions are usually mild and go away on their own after the antibiotic is stopped.

The boxed warning: tendons, nerves and muscle weakness

Ciprofloxacin carries a boxed warning because it has been associated with serious adverse reactions involving the tendons, nervous system and muscles. These reactions can occur within hours to days of starting ciprofloxacin and may persist for several months after treatment is complete.

Tendon Rupture: Ciprofloxacin can cause tendinitis or tendon rupture in all ages. The risk of tendon rupture is higher in people over 60 years old, patients taking corticosteroid drugs, and those with kidney, heart, or lung transplants. Tendinitis and tendon rupture can occur within hours to days after starting ciprofloxacin therapy.

Ciprofloxacin should also be avoided in patients taking tizanidine, a muscle relaxant.

Ciprofloxacin with food, dairy and antacids

Ciprofloxacin can be taken with or without food. Taking ciprofloxacin with food may reduce the chance of stomach upset. However, it is important to take ciprofloxacin at least 2 hours before or after taking any antacids, calcium supplements, iron supplements, or other products containing calcium, magnesium, aluminum, zinc, or iron.

Ciprofloxacin interactions and alcohol

Ciprofloxacin tablets are also not suitable for people who are taking other medicines that contain the same ingredient, such as other quinolone antibiotics or tizanidine (a muscle relaxant).

Ciprofloxacin is not known to be harmful when taken with alcohol. However, it's always a good idea to speak with your healthcare provider before combining any medications or supplements with alcohol.

How long to take ciprofloxacin

How long the course lasts depends on the type of infection that's being treated. Your doctor will tell you how many tablets you need and for how long to take them for.

It's usually taken twice a day until you've finished your course.

Ciprofloxacin price and prescription

GoodRx national coupon vs average retail, last updated 07/16/26.

Ciprofloxacin is a prescription antibiotic in the U.S., and it's available by prescription only. It treats bacterial infections, including those that affect the urinary tract, skin, respiratory tract, bones, and joints.

Ciprofloxacin is a prescription antibiotic in the U.S., and prices vary based on the dosage strength, quantity, and pharmacy.

Sources

1. DailyMed: CIPRO (ciprofloxacin) tablet
2. GoodRx: Ciprofloxacin prices
3. FDA BeSafeRx: Considering an online pharmacy?

Reader consultation

Your questions, answered by Dr. Marta Reyes, MD

Family medicine, dermatology & infectious disease

Marta Reyes answers reader questions on ciprofloxacin tablets.

Nadia asked: my heel started aching on day three of cipro. Should I finish the course?

You may be having an adverse effect of the drug known as tendonitis, or inflammation of tendons. Although uncommon, it can be serious. Do not continue taking this antibiotic if these symptoms occur.

Pavel asked: can I have yogurt or a banana while I take ciprofloxacin?

Bananas are fine, but yogurt and milk products may interfere with the effectiveness of Cipro (Ciprofloxacin), since they contain calcium that binds to antibiotics and makes them less effective.

Joan asked: what pain reliever can I take with ciprofloxacin?

Acetaminophen is usually the simpler choice because it causes less stomach irritation.

Ravi asked: I have leftover cipro from last year. Can I use it for a cough?

Leftover ciprofloxacin is not a good idea as an antibiotic for the treatment of a cough. Cough is usually caused by a viral infection (e.g., rhinovirus) and antibiotics such as cipro are ineffective against viruses.

General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.