Does Cipro (ciprofloxacin) prolong the QT interval?

From the Guidelines

Yes, Ciprofloxacin (Cipro) can prolong the QT interval, as indicated in the study published in Pediatrics 1, which lists Ciprofloxacin as one of the fluoroquinolones that can prolong the QT interval. This QT prolongation increases the risk of developing a potentially dangerous heart rhythm called Torsades de Pointes, particularly in susceptible individuals. Some key points to consider when prescribing Cipro include:

• Patients with pre-existing QT prolongation, electrolyte abnormalities (especially low potassium or magnesium), heart failure, bradycardia, or those taking other QT-prolonging medications are at higher risk.
• When prescribing Cipro, clinicians should consider obtaining a baseline ECG in high-risk patients and monitor for symptoms like palpitations, dizziness, or syncope during treatment.
• The mechanism involves ciprofloxacin blocking potassium channels in cardiac cells, which delays cardiac repolarization and extends the QT interval.
• If Cipro is necessary for a patient with risk factors, close monitoring is essential, and correcting electrolyte abnormalities before starting treatment may reduce risk, as suggested by the study in Annals of Oncology 1.
• Alternative antibiotics should be considered for patients with significant cardiac risk factors when appropriate. It's also important to note that the study in Blood 1 recommends avoiding the concomitant use of drugs that are known to prolong the corrected QT (QTc) interval, such as ciprofloxacin, and suggests strict monitoring for ECG changes in patients with previous episodes of significant QTc prolongation or torsades de pointes.

From the FDA Drug Label

Ciprofloxacin Tablets USP may cause a rare heart problem known as prolongation of the QT interval. This condition can cause an abnormal heartbeat and can be very dangerous The chances of this event are higher in people: who are elderly with a family history of prolonged QT interval with low blood potassium (hypokalemia) who take certain medicines to control heart rhythm (antiarrhythmics) In general, elderly patients may be more susceptible to drug-associated effects on the QT interval. Therefore, precaution should be taken when using Ciprofloxacin Tablets USP 250 mg, 500 mg and 750 mg with concomitant drugs that can result in prolongation of the QT interval (e.g., class IA or class III antiarrhythmics) or in patients with risk factors for torsade de pointes (e.g., known QT prolongation, uncorrected hypokalemia)

Yes, Cipro (ciprofloxacin) may prolong the QT interval, especially in certain populations such as the elderly, those with a family history of prolonged QT interval, and those with low blood potassium (hypokalemia) 2, 2, 2.

• Key factors that increase the risk of QT prolongation include:
  • Elderly patients
  • Family history of prolonged QT interval
  • Low blood potassium (hypokalemia)
  • Concomitant use of certain medicines to control heart rhythm (antiarrhythmics)
• Precautions should be taken when using Ciprofloxacin Tablets USP with concomitant drugs that can result in prolongation of the QT interval or in patients with risk factors for torsade de pointes.

From the Research

Ciprofloxacin and QT Interval Prolongation

• Ciprofloxacin, a fluoroquinolone antibiotic, has been studied for its potential to prolong the QT interval, a change in the heart's electrical activity that can increase the risk of arrhythmias and cardiac arrest.
• Some studies suggest that ciprofloxacin may not significantly prolong the QT interval in most patients. For example, a study published in 2017 found that intravenous ciprofloxacin did not prolong the QT interval in ICU patients with additional co-morbidities and risk factors 3.
• However, other studies have reported cases of ciprofloxacin-induced QT interval prolongation and torsades de pointes, a potentially life-threatening arrhythmia. A study published in 2004 reported two cases of ciprofloxacin-induced acquired long QT syndrome, with marked QTc prolongation and recurrent syncope 4.
• Another study published in 2009 reported a case of ciprofloxacin-induced acquired long QT syndrome in a patient under class III antiarrhythmic therapy, with documented torsades de pointes and recurrent syncope 5.
• A prospective evaluation of 38 consecutive patients receiving ciprofloxacin or levofloxacin found no significant change in the mean QTc interval in patients receiving ciprofloxacin, although there was a small but significant increase in the longest QTc intervals over baseline in patients receiving levofloxacin 6.
• A case report published in 2012 highlighted a rare but potentially fatal side effect of ciprofloxacin, with a 65-year-old man presenting with recurrent seizure-like activity and torsades de pointes due to ciprofloxacin-induced QT interval prolongation 7.

Risk Factors and Considerations

• Patients with predisposing factors, such as concomitant medications or underlying heart disease, may be at increased risk of ciprofloxacin-induced QT interval prolongation and torsades de pointes.
• Electrolyte disturbances, such as hypokalemia or hypomagnesemia, may also increase the risk of QT interval prolongation and arrhythmias.
• Healthcare providers should be aware of the potential risks and monitor patients closely for signs of QT interval prolongation and arrhythmias, especially in high-risk patients.