Ciprofloxacin (Cipro) fights a number of bacterial infections in the body. This medication belongs to the fluoroquinolone class of antibiotics and comes in tablet, liquid and intravenous forms. Ciprofloxacin is prescribed to treat urinary tract infections as well as certain skin, respiratory, intestinal and sexually transmitted diseases. It can also treat anthrax, a type of bacteria used in bioterrorism. Ciprofloxacin can have a variety of side effects, most commonly gastrointestinal symptoms such as vomiting or diarrhea. Rarely, ciprofloxacin can affect tendons, nerves, muscles or the heart.
The most frequent side effect of ciprofloxacin is irritation of the stomach and intestines. According to the Merck Manual Professional Edition, up to 5 percent of people who take ciprofloxacin report symptoms such as nausea, vomiting, upper abdominal discomfort, heartburn or diarrhea. If diarrhea is severe, it may be because ciprofloxacin has altered the naturally occurring bacteria in the intestines. This imbalance can lead to an infection of the colon with the bacterium Clostridium difficile, which requires treatment with a different type of antibiotic.
A serious side effect of taking ciprofloxacin is tendinitis -- painful swelling and irritation of tendons, the fibrous tissues that connect bones to muscles. Tendinitis can occur as soon as 48 hours after starting ciprofloxacin. Severe tendinitis can actually cause the tendon to tear. The most common tendon affected by ciprofloxacin is the Achilles tendon, which is located behind the ankle. Tendons in the shoulder and hand can also be affected. Tendinitis or tendon rupture associated with ciprofloxacin use is more common in people over 60 years of age and those taking corticosteroid medications.
Rarely, ciprofloxacin can cause damage to the nerves of the arms and legs -- known as neuropathy. Symptoms of neuropathy include tingling, burning or numbness of the limbs. Ciprofloxacin can also cause dizziness, headaches, tremors or nervousness. Rarely, the drug can trigger seizures, which are most likely to occur in people who already suffer from a disorder affecting the brain. For people with myasthenia gravis, ciprofloxacin can worsen their muscle weakness.
In older individuals, or those with underlying heart problems, ciprofloxacin can cause an abnormal heart rhythm. This can make a person feel palpitations -- a sensation that his heart is fluttering or racing. People at a particularly increased risk for abnormal heart rhythms are those who already take medications to correct their heart rhythms or who take certain medications that interact with ciprofloxacin.
Warnings and Precautions
Seek emergency medical attention for symptoms of an allergic reaction to ciprofloxacin, which may include a rash, itching, shortness of breath, lightheadedness or swelling. Also seek prompt medical attention for serious side effects such as severe diarrhea, trouble holding down food or liquids, severe muscular pain, tingling or numbness of your limbs or an irregular heartbeat. Finally, it is important to discuss all of your medical problems and any medications you are taking with your physician before you start ciprofloxacin.
- Merck Manual Professional Edition: Fluoroquinolones
- U.S. Food and Drug Administration: Information for Healthcare Professionals: Fluoroquinolone Antimicrobial Drugs
- U.S. Food and Drug Administration: FDA Drug Safety Communication: FDA Requires Label Changes to Warn of Risk for Possibly Permanent Nerve Damage From Antibacterial Fluoroquinolone Drugs Taken by Mouth or by Injection
- Drugs.com: Cipro Side Effects