Ciprofloxacin vs Levofloxacin: side effects in FDA adverse event reports
At a glance
| Ciprofloxacin | Levofloxacin | |
|---|---|---|
| Drug class | – | Fluoroquinolone Antibacterial |
| Brand names | – | – |
| FAERS reports | 96,695 | 59,938 |
| Serious | 83% | 88% |
| Death outcome | 9,728 | 8,134 |
| Boxed warning | Yes SERIOUS ADVERSE REACTIONS INCLUDING TENDINITIS, TENDON RUPTURE, PERIPHERAL NEUROPATHY, CENTRAL NERVOUS SYSTEM EFFECTS AND EXACERBATION OF MYASTHENIA GRAVIS • Fl | Yes SECTION WARNING: SERIOUS ADVERSE REACTIONS INCLUDING TENDINITIS, TENDON RUPTURE, PERIPHERAL NEUROPATHY, CENTRAL NERVOUS SYSTEM EFFECTS AND EXACERBATION OF MYAST |
Signals both drugs share
| Reaction | Ciprofloxacin | Levofloxacin | Label screen (A / B) |
|---|---|---|---|
| Tendonitis | 2,268 · PRR 36.9 | 1,145 · PRR 27.7 | Labeled — boxed warning / Labeled — boxed warning |
| Tendon pain | 2,035 · PRR 79.7 | 1,070 · PRR 57.5 | Labeled (related wording) / Labeled (related wording) |
| Tendon disorder | 1,135 · PRR 45.5 | 632 · PRR 37.4 | Labeled adverse reaction / Labeled adverse reaction |
| Tendon discomfort | 253 · PRR 109.5 | 131 · PRR 73.4 | Labeled (related wording) / Not in label — unassessed |
| Nephrogenic anaemia | 755 · PRR 41.7 | 341 · PRR 27.5 | Not in label — unassessed / Not in label — unassessed |
| Rebound acid hypersecretion | 437 · PRR 35.9 | 244 · PRR 30.2 | Not in label — unassessed / Not in label — unassessed |
| Hyperparathyroidism secondary | 415 · PRR 42.4 | 166 · PRR 24.5 | Not in label — unassessed / Not in label — unassessed |
| Chronic kidney disease-mineral and bone disorder | 192 · PRR 47.0 | 89 · PRR 31.5 | Not in label — unassessed / Not in label — unassessed |
| Dysbiosis | 119 · PRR 37.7 | 110 · PRR 55.6 | Not in label — unassessed / Not in label — unassessed |
| Small fibre neuropathy | 93 · PRR 31.5 | 68 · PRR 35.8 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Ciprofloxacin
- Chronic kidney disease — n=4,554, PRR 13.6 Labeled (related wording)
- Tendon rupture — n=1,303, PRR 25.4 Labeled — boxed warning
- Clostridium difficile colitis — n=586, PRR 12.6 Labeled (related wording)
- Tendon injury — n=341, PRR 21.7 Labeled (related wording)
- Muscle rupture — n=235, PRR 13.9 Labeled (related wording)
- Asthma-chronic obstructive pulmonary disease overlap syndrome — n=152, PRR 89.4 Labeled (related wording)
- Pseudomembranous colitis — n=145, PRR 14.9 Labeled adverse reaction
- Musculoskeletal injury — n=83, PRR 113.3 Labeled (related wording)
Labeled signals distinctive to Levofloxacin
- Respiratory symptom — n=236, PRR 32.1 Labeled (related wording)
- Vascular purpura — n=104, PRR 28.2 Labeled (related wording)
Common questions
Which has more reported side effects, Ciprofloxacin or Levofloxacin?
Ciprofloxacin has 96,695 FAERS reports and Levofloxacin 59,938. More reports does not mean more dangerous: volume follows how widely and how long a drug has been used, prescription vs over-the-counter status, and publicity. The seriousness share (83% vs 88%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Ciprofloxacin and Levofloxacin share?
Both drugs carry disproportionality signals for tendonitis, tendon pain, tendon disorder, tendon discomfort, nephrogenic anaemia. Shared signals often reflect a shared drug class or the condition both are used for.
Is Ciprofloxacin or Levofloxacin safer?
FAERS cannot answer that: it has no denominator and no comparator. Use this page to see which risks are already on each label and which signals are unlabeled, then check the prescribing information and your clinician for your situation.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, openFDA count queries for seriousness and deaths. Pair chosen because it is a commonly searched comparison. Generated 2026-10-08.