Nursing care
Ciprofloxacin: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 3 min read · Updated September 2026
Short answer
Ciprofloxacin is a fluoroquinolone that disrupts bacterial DNA replication, used for urinary, respiratory, and gastrointestinal infections. Its most serious risk is tendon rupture, particularly of the Achilles tendon, especially in older adults and those on corticosteroids. Any tendon pain or swelling during therapy means stop the drug and notify the prescriber immediately.
Mechanism, simply
Ciprofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, the enzymes bacteria need to unwind and replicate their DNA. Without them, the bacterial chromosome cannot uncoil properly, replication stalls, and the cell dies.
This mechanism gives ciprofloxacin broad activity against gram-negative organisms in particular, including Pseudomonas aeruginosa, which is why it shows up so often in complicated urinary and hospital-acquired infections where gram-negative coverage is needed.
Indications you will see on the ward
Ciprofloxacin is used for complicated urinary tract infections and pyelonephritis, where its tissue penetration reaches the kidney, unlike nitrofurantoin. It also covers certain gastrointestinal infections, some respiratory infections, bone and joint infections, and anthrax prophylaxis or treatment.
Because of its safety profile, current guidance reserves fluoroquinolones for situations where alternative antibiotics are not suitable, given the risk of serious adverse effects. Expect to see it used more selectively than in past years, often after other options have failed or are contraindicated.
Assessment before administration
Ask about tendon problems, joint disorders, and current or recent corticosteroid use, since these markedly raise the risk of tendon injury. Confirm the patient's age, as adults over 60 carry higher risk, and note any personal or family history of aortic aneurysm or dissection, since fluoroquinolones carry a warning for this too.
Check for a history of seizure disorder or myasthenia gravis, both of which can be worsened by fluoroquinolones, and review renal function since dose adjustment is needed in impairment. Screen for QT-prolonging conditions or medications before the first dose.
Toxicity and the antidote
There is no specific antidote for ciprofloxacin toxicity. Serious adverse effects include tendon rupture, peripheral neuropathy that can be irreversible, CNS effects such as seizures and confusion, and QT prolongation with risk of torsades de pointes.
Management is supportive and centres on early recognition: stop the drug at the first report of tendon pain, swelling, or weakness, and monitor cardiac rhythm if QT prolongation is a concern. Symptoms of peripheral neuropathy, numbness, tingling, or burning pain, also warrant immediate discontinuation to limit permanent nerve damage.
Interactions that matter
Antacids, sucralfate, and products containing calcium, iron, zinc, or magnesium chelate ciprofloxacin and drastically reduce its absorption; separate dosing by at least two hours before or six hours after these products. Ciprofloxacin inhibits the CYP1A2 enzyme, raising theophylline and caffeine levels and increasing the risk of toxicity or seizures.
It also potentiates warfarin, requiring closer INR monitoring, and combining it with corticosteroids substantially increases tendon rupture risk, which is exactly the population that needs the closest tendon assessment. NSAIDs taken alongside ciprofloxacin can increase the risk of CNS stimulation and seizures.
What the patient must be told
Stop the medication and call the prescriber immediately at the first sign of tendon pain, swelling, or a snapping sensation, particularly in the Achilles tendon at the back of the ankle. This risk is higher in older adults and anyone currently or recently taking a corticosteroid.
Avoid strenuous exercise during treatment as a precaution. Take the drug apart from antacids, calcium, or iron supplements by several hours, and use sun protection since photosensitivity is common. Report any new muscle weakness, tingling, confusion, or irregular heartbeat without delay.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our pharmacology practice questions are the closest set to what this page covers.
One question from the pharmacology set
A client with heart failure is started on furosemide 40 mg PO daily. Which findings should the nurse report to the provider before administering the next dose? Select all that apply.
Rationale
Furosemide is a loop diuretic, so the two things you are watching are potassium and kidney function. A potassium of 2.9 mEq/L is below the 3.5–5.0 reference range and puts the client at risk for dysrhythmia — hold and report. Muscle cramps with palpitations are the clinical face of that same hypokalemia, so they are reported together, not separately. A creatinine that doubles signals the diuresis has outrun renal perfusion. A blood pressure of 132/78 and a 1 kg loss are the expected response to the drug working, not reasons to hold it.
Answer: A, D, E
Common questions
Who is most at risk of tendon rupture on ciprofloxacin?
Older adults, especially those over 60, and anyone taking or recently taking corticosteroids carry the highest risk. Organ transplant recipients are also at increased risk. The Achilles tendon is the most commonly affected site.
What should a nurse do if a patient reports tendon pain while on ciprofloxacin?
Hold the next dose, notify the prescriber immediately, and advise the patient to rest the affected limb and avoid exercise. The drug is typically discontinued and an alternative antibiotic considered.
Why can't ciprofloxacin be taken with antacids?
Polyvalent cations like calcium, magnesium, iron, and zinc chelate ciprofloxacin in the gut and significantly reduce its absorption, weakening the antibiotic's effectiveness. Doses should be separated by at least two hours before or six hours after these products.
Is ciprofloxacin safe for pyelonephritis when nitrofurantoin is not?
Yes. Ciprofloxacin achieves therapeutic concentrations in kidney tissue, unlike nitrofurantoin, which stays confined to the bladder. This tissue penetration is exactly why it is used for kidney infections and nitrofurantoin is not.
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