Devastating and Surprising Side Effects of Ciprofloxacin – C... (2023)

Over 20 million people take a class of antibiotics called fluoroquinolones annually for everything from sinusitis and urinary tract infections to bronchitis and skin infections. Two of the most famous drugs in this category of medicines are ciprofloxacin (Cipro) and levofloxacin (Levaquin).

When people get a prescription for an antibiotic they often anticipate digestive tract upset–nausea, vomiting, stomach cramps and diarrhea. What they do not expect are hallucinations, tendon rupture, nerve damage or brain fog. And they certainly do not expect such side effects to be permanent.

The FDA Can Be Super Slow

It took the FDA a very long time to warn prescribers and patients about the surprising side effects of ciprofloxacin and similar antibiotics. Two years ago the agency admitted that nerve damage–peripheralneuropathy (pain, burning, tingling, numbness and weakness)–can occur after taking only a few pills and can last for months or years. In some cases the damage may be permanent.

Over the last 20 years we have heard from an extraordinary number of people that drugs like ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin and ofloxacin can cause chaos. Some patients refer to the adverse reactions as being “floxed.”

Surprising Side Effects of Ciprofloxacin: Hallucinations

Most people would never associate horrible nightmares and hallucinations with an antibiotic. And yet we have heard from many people that quinolone antibiotics can do just that.


“My son who is 12 was prescribed ciprofloxacin for a bacterial infection. As soon as he started taking it, he had nausea and vomiting. He complained of tingling sensations in his fingers the next day and started suffering from insomnia and hallucinations.

“The doctor gave him something for the nausea and we continued giving him the antibiotic. He started having anxiety and nervousness and also the hallucinations continued. This medicine has brought so much pain to our son and ourselves mentally and physically. I wish I knew the serious side effects of this medicine before giving it to him.”


“I have been prescribed levofloxacin for pneumonia. It worked wonders for my very high fever and lung infection but I have been beside myself with dizziness, rapid heart beats and nausea. My doctor warned me about tendon problems but no nightmares, dizziness, major insomnia and hallucinations. I am two days off the medicine and the mental disturbances are still here.”


“I took Cipro as a completely healthy 29-year-old male and it almost killed me. On the sixth day after starting Cipro for a stomach bug I felt a tight pain in my side that then progressed to heart palpitations, hallucinations, nightmares, insomnia, suicidal thoughts, memory loss, depersonalization, nerve pain, loss of feeling in my hands and feet, tendonitis and loss of taste.

“I lost 19 pounds in two weeks and was very lean to begin with. This occurred 11 months ago and I am still not completely recovered, but am doing much better and expect a full recovery.”

Tendon Disasters

Other surprising side effects ofciprofloxacin, levofloxacin and similar antibiotics aretendon and soft tissue damage. Again, most people never imagine that the medicine they are taking for sinusitis or a urinary tract infection could cause a tendon to rupture and leave them disabled.


“I was prescribed ciprofloxacin and have had multiple tendon and ligament ruptures, permanent double vision and peripheral neuropathy. It was confirmed by my doctors the ciprofloxacin was the cause.”


“Itook Cipro for almost month. About the third week I was so messed up I thought I was dying. The antibiotic made me feel awful. I had tendon problems in my Achilles heel and now in my hands and fingers. I can’t even bend my fingers open and closed. They just get stuck (stiff). I know it was the Cipro!”


“My most recent drug harm was from the antibiotic ciprofloxacin. I suffered Achilles tendon tightness and pain, which became an Achilles tendon rupture.

“The doctor’s office said it could not be caused by the drug. A second doctor put ‘tenderness’ on my chart but prescribed a boot cast and anti-inflammatory drugs.

“I read the ciprofloxacin page on Wikipedia and found out this tendon harm, damage and rupture is a KNOWN side effect of the drug. Worse yet, I found out it is NOT to be prescribed to patients my age. I took it for three days, and suffered over two years with inability to walk normally.”

Nerve Damage

It has been our experience that patients are not adequately warned about irreversible damage to nerves. This condition is sometimes called peripheral neuropathy and it can be devastating.


“The doctor put me on Cipro for a tear duct infection. I took one pill before bed and by the next morning I was feeling like crap. I took another pill at 7 am and by 10 am my right leg was hurting so bad. It also felt like I was walking on needles. I also had pain in my shoulders and neck muscles.

“About 1:30 pm I had enough and called the doctor who said to go to the walk in clinic. I went and the doctor told me to stop taking the medication. If I got that sick after taking only 2 pills I can just imagine what would have happened if I had taken it for the full 7 days.”


“I have been given Cipro [ciprofloxacin] about 5 times in the last decade. The first time it was prescribed for a routine infection when I was about 30. I was an athletic person and used to be superior to 90% of my friends in physical strength and agility.

“After taking this antibiotic all my joints and muscles have been crippled – feet, heels, ankles, knees, hips, neck, shoulders, elbows, wrists and fingers. I suffer from brain fog, increased forgetfulness, dry eyes, dry mouth, dry skin, nerve damage, peripheral neuropathy with loss of sensation and involuntary twitching and jerking of muscles. I have lost physical balance and have a tendency to fall. I experience emotional ups and downs and am not able to remember correct words during speech.

“I am so crippled that, when I enter a car, I need to help my left leg with my hands to lift it into the car. Sleeplessness is another major issue. If you can’t sleep your recent memory/experiences will not imprint on your brain. I already look and feel like 90 years old.

“The saddest thing is that doctors never listen to me and do not buy into ciprofloxacin as the cause of my misery. By giving you a fluoroquinolone antibiotic, they have created a brand new patient for life, who feeds the entire ill-health industry for remainder of his/her life. They call the conditions I suffer from fibromyalgia, psoriasis, arthritis, tendonitis, neuropathy and several other names. Specialists start treating these conditions with more drugs.”


“My life has been utterly destroyed in the most horrible manner by ciprofloxacin. I am far too sick and weary at this point to describe to you all my points of misery. I see no light at the end of the tunnel. Nor did I do anything to cause this misery. I lived an exemplary life, always cognizant of the importance of good health and took excellent care of myself.

“Though I was completely healthy in every way, I decided it would probably be a good idea to go in for a ‘wellness’ check. I would still be completely healthy today had the doctor not asked for a urine sample ‘as general procedure.’ Because the urine sample looked ‘slightly cloudy,’ to her, she prescribed ciprofloxacin, 500mg, two times per day for 7 days.

“This was, as she said, ‘a simple antibiotic, for just in case.’ I had never had a urinary tract infection before and had no discomfort of any sort, but I figured it was possible. So like a good soldier, I filled the prescription and took every last pill, as instructed. No one bothered to call during that week to inform me that the urine culture was negative.

“As far as I’m concerned, I died July, 2014.

“I’m writing this because I’m so sick of doctor-worshiping people blaming the victim. I’ve seen and heard too much of it! I never again want to hear or see in writing that there must have been something wrong with the victim of this awful poison to begin with!

“Wake up! What does it take to convince you that people are being poisoned wholesale by drug companies. Even as I struggle to write this there are untold numbers of us out here suffering the effects of these fluoroquinolines and not ONE of us appreciates being blamed for it in any way shape or form, thank you!”

Heart Rhythm Irregularities

Irregular heart rhythms are a rare but potentially life-threatening complication of fluroquinolones. These too are surprising side effects of ciprofloxacin and company.

One of the most serious arrhythmias is something called a prolongation of the QT interval. If this happens it could lead to deadly consequences such as cardiac arrest. Symptoms can include dizziness or fainting. A doctor should always warn a patient about such side effects and yet many of the reports above mention these adverse reactions but most people were clearly not prepared for them.


“I have been taking ciprofloxacin now for 4 days and I must stop. I have a bladder infection but these side effects are so dangerous. Old shoulder injuries are now killing me with pain. I am experiencing crazy nightmares, heart palpitations and heart spasms.

“I bet people die from this stuff. I’m done. I’ll have to find a much safer way to treat my infection. I’m terrified these symptoms may not go away.”

The Bottom Line

We know that many people take fluoroquinolones without experiencing serious or life-changing side effects. For them, the drugs are valuable. For others, though, this class of antibiotics is poison. Sadly, we do not yet know what predisposes some people tosurprising side effects of ciprofloxacin and its chemical cousins. These adverse reactions can be life altering.

The best advice we can offer is to be absolutely vigilant. If a physician prescribes a quinolone-type drug, ask about the side effects we described above. If you or someone you care about begins to experience any of these side effects, contact the prescriber immediately. We do not want anyone to go through what these people have suffered.

Share your own experience with fluoroquinolones below in the comment section and please vote on this article at the top of the page.

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