Fluoroquinolones increase the risk of tendon rupture and aortic aneurysm/dissection, and some antibiotics increase C. difficile infection risk (archive bibliography on harms).
Original statement
No Arabic original wording available.
Translation
Fluoroquinolones increase the risk of tendon rupture and aortic aneurysm/dissection, and some antibiotics increase C. difficile infection risk (archive bibliography on harms).
Origin
- Source status
- Archive editors
- Attribution
- Archive editors (eltayebat.com)
- Origin
- https://eltayebat.com/rule/antibiotic-overuse/
- Attribution uncertainty
- Archive bibliography (A-ABX-12, A-ABX-14, A-ABX-15, A-ABX-16, A-ABX-21); not discussed in the narrative.
- Claimed mechanism
Collagen degradation; microbiome disruption.
- Claimed health effect
Tendon rupture, aortic events, C. difficile.
- Population concerned
Adults
- Geographic restriction by Elawady
none found
Scientific assessment
Mostly true – Correct at its core, but with limitations or minor inaccuracies.
Certainty of evidence: moderate – Further research may still affect the assessment.
1. What was claimed?
Specific antibiotic harms.
2. What is demonstrably correct?
Achilles tendon rupture OR 4.3 (2.4-7.8) for current quinolone use (A-ABX-14); meta-analysis OR 2.52 (1.81-3.52) for rupture and 3.95 for tendinitis (I-ABX-122); C. difficile: clindamycin OR 16.80, fluoroquinolones OR 5.50 (A-ABX-12); penicillin-allergy label associated with MRSA (aHR 1.69) and C. difficile via alternative antibiotics (A-ABX-21); aortic aneurysm/dissection RR 2.43 (A-ABX-15) and HR 1.66 (1.12-2.46), 82 extra cases per million episodes (A-ABX-16).
3. What is wrong or exaggerated?
The aortic risk is contested: compared with cephalosporins or trimethoprim, the association disappeared in a UK study (adjusted HR 1.03, 0.91-1.17; I-ABX-123) and in a 13.6-million-patient multinational study (HR 0.91 and 1.01; I-ABX-124), suggesting confounding by indication. All are drug-specific, mostly rare harms; they argue for careful drug choice, not for avoiding all antibiotics.
4. What remains unclear?
Absolute risks for an individual depend on age and underlying disease and were not extracted from all studies.
5. Which studies support it?
A-ABX-12, A-ABX-14, A-ABX-15, A-ABX-16, A-ABX-21.
6. Which studies contradict it?
Aortic element: I-ABX-123 (UK, adjusted HR 1.03 vs cephalosporins) and I-ABX-124 (multinational, calibrated HR 0.91-1.01). None against the tendon and C. difficile harms.
7. What applies to Germany and Europe?
Data come partly from the UK and Sweden (see studies), so they are directly relevant to Europe.
8. What is known about Egypt?
No Egyptian data were reviewed; the drug-specific risks apply wherever these antibiotics are used.
9. What practical conclusion is appropriate?
Known side effects are weighed against benefit by prescribers.
Assessment details
- Rationale for certainty of evidence
Tendon and C. difficile harms: consistent findings across case-control and cohort studies and meta-analyses (e.g. Achilles rupture OR 2.52, I-ABX-122). Aortic aneurysm/dissection: earlier associations (A-ABX-15, A-ABX-16) were not confirmed by two rigorous active-comparator studies (I-ABX-123, I-ABX-124). Absolute risks are low.
- Source quality
Peer-reviewed pharmacoepidemiology.
- Regional transferability
High (UK, Sweden, Taiwan data).
- Individual exceptions
Elderly patients on corticosteroids have the highest tendon risk.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 26 October 2026 provisional
Scientific evidence in detail
True only under certain conditions – The claim holds only for certain doses, groups of people, preparations or circumstances.
Research question: Do fluoroquinolones increase the risk of tendon rupture and aortic aneurysm/dissection, and do some antibiotics increase C. difficile infection?
Research question in detail (PECO)
- Population
- Adults
- Intervention or exposure
- Fluoroquinolones; clindamycin and other antibiotics
- Comparison
- Non-use or other antibiotics
- Geographic scope
- Universal pharmacology
- Outcomes
- Achilles tendon rupture
- Aortic aneurysm/dissection
- C. difficile infection
Study results as reported by the authors. Our assessment follows below.
What speaks for the claim?
Fluoroquinolones raise tendon injury risk
Alves C et al.. Eur J Clin Pharmacol 2019 · PMID 31270563 · DOI 10.1007/s00228-019-02713-1 Meta-analysisabstract checkednewly addedMeta-analysis of 15 studies.
- Actual result
- Achilles rupture OR 2.52 (1.81-3.52); tendinitis 3.95 (3.11-5.01).
- Methodological quality
- moderate
- Relevance
- direct
- Limitations
- Heterogeneity.
Antibiotics and C. difficile
Brown KA et al.. Antimicrob Agents Chemother 2013 · PMID 23478961 · DOI 10.1128/AAC.02176-12 Meta-analysisabstract checkedMeta-analysis of community C. difficile.
- Actual result
- Clindamycin OR 16.80; fluoroquinolones OR 5.50.
- Methodological quality
- moderate
- Relevance
- direct
Fluoroquinolones and aortic aneurysm (Sweden)
Swedish cohort.
- Actual result
- Aortic HR 1.66 (1.12-2.46); 82 extra cases per million episodes.
- Methodological quality
- moderate
- Relevance
- direct
- Limitations
- Active comparator amoxicillin.
What speaks against the claim?
UK study finds no aortic risk from fluoroquinolones after fair comparison
Brown JP et al.. JAMA Cardiol 2023 · PMID 37585175 · DOI 10.1001/jamacardio.2023.2418 Cohort studyabstract checkednewly addedUK cohort + case-crossover with active comparators.
- Actual result
- Adjusted HR 1.03 (0.91-1.17) vs cephalosporins; no association vs other antibiotics.
- Methodological quality
- high
- Relevance
- direct
International study: no aortic risk from fluoroquinolones for urinary infections
Janetzki JL et al.. EClinicalMedicine 2025 · PMID 39975698 · DOI 10.1016/j.eclinm.2025.103096 Cohort studyabstract checkednewly added13.6 million patients, 5 countries, calibrated.
- Actual result
- HR 0.91 (0.73-1.10) vs trimethoprim; 1.01 (0.82-1.25) vs cephalosporins.
- Methodological quality
- high
- Relevance
- direct (UTI only)
- Limitations
- UTI indication only.
What does the overall evidence say?
Editorial assessment based on the studies above – not itself a study result.
Which position is better supported?
Tendon injury and C. difficile risks are well established and drug-specific. The aortic aneurysm/dissection association is contested: the most rigorous active-comparator studies (2023, 2025) found none.
Why some studies weigh more
Designs with active comparators and negative-control calibration weigh most for the aortic question.
Is a causal relationship established? Probable Tendon and C. difficile: consistent, strong associations and plausible mechanisms. Aortic: possible but not established.
Remaining uncertainty
Aortic risk in specific high-risk subgroups.
Justified conclusion
Mostly correct; the aortic element is uncertain.
Why do studies seem to disagree?
Earlier aortic studies (A-ABX-15, A-ABX-16) vs newer active-comparator studies (I-ABX-123, I-ABX-124): confounding by indication (sicker patients receive fluoroquinolones) explains much of the earlier associations.
Does this depend on the country?
- General biological effects
- Universal pharmacology.
- Eating habits
- Not applicable (medicine use, not diet).
- Legal rules
- Regulators (FDA, EMA) restricted fluoroquinolone use (not fetched here).
- Actual monitoring data
- Not applicable.
A regional difference that changes the conclusion is not supported by robust data.
Statistical re-check
- Crude vs adjusted – Crude HR 1.28 -> adjusted 1.03; all CIs log-symmetric. recalculated
- CI symmetry – OR 2.52 (1.81-3.52) symmetric; I2 76.7% (heterogeneous). recalculated
Certainty of the overall evidence (GRADE, simplified)
- Main outcome
- Tendon rupture with fluoroquinolones
- Starting level
- low (observational studies)
- Reasons for downgrading
- inconsistency (I2 77%)
- Reasons for upgrading
- large effect
- dose/age gradient
- Result
- moderate
Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.
Search strategy
Documented literature searches for this review (search strings in the original database syntax).
| Database | Date | Search | Looking for | Hits | Included |
|---|---|---|---|---|---|
| Europe PMC | 26 October 2026 | TITLE:(fluoroquinolone*) AND TITLE:(aortic OR aneurysm OR dissection) AND PUB_YEAR:[2019 TO 2026] AND (cohort OR "meta-analysis" OR "case-crossover" OR "self-controlled") | both directions | 42 | |
| Europe PMC | 26 October 2026 | TITLE:(fluoroquinolone* OR quinolone*) AND TITLE:(tendon OR tendinopathy OR "tendon rupture") AND (PUB_TYPE:"Systematic Review" OR TITLE:"meta-analysis") | supporting evidence | 6 |
Open questions
Aortic risk in patients with known aneurysm.
How deeply was this checked?
8 linked studies: 0 checked in full text (0 of them with a structured risk-of-bias assessment), 8 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.
Last scientific review: 26 October 2026
History of the verdict
- 25 October 2026 · Phase 1 · Initial assessment: Mostly true (moderate)
- 26 October 2026 · Phase 4 (systematic evidence review) · Re-examined with extended evidence; verdict unchanged: Mostly true (moderate)
Tendon and C. difficile elements confirmed; aortic element weakened by two rigorous null studies. Overall verdict unchanged because the claim bundles three harms and two remain well supported.
New sources: I-ABX-122 I-ABX-123 I-ABX-124
In plain language
Some antibiotics have rare but serious side effects, such as tendon tears with fluoroquinolones, or a gut infection called C. difficile after some antibiotics. These risks are real and well documented. A link between fluoroquinolones and tears of the main artery was reported earlier, but newer, more careful studies did not confirm it. These risks are a reason to choose antibiotics carefully, not to avoid them when needed.
Studies on this claim
Studies supporting the claim (6)
-
Antibiotics and C. difficile
Brown KA et al.. Antimicrob Agents Chemother 2013 · PMID 23478961 · DOI 10.1128/AAC.02176-12Meta-analysiscited by the Tayebat archiveabstract checkedSome antibiotics (e.g. clindamycin) strongly raise C. difficile risk; tetracyclines did not.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Compare classes.
- How was the study done?
Meta-analysis.
- How many people, animals or samples were studied?
7 studies.
- What was actually found?
Varies by class.
- How large was the observed effect?
OR up to 16.8.
- What do the results mean in everyday life?
Choose antibiotics carefully.
- What are the study's limitations?
Few studies.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
High.
-
Quinolones and Achilles tendon rupture
van der Linden PD et al.. Arch Intern Med 2003 · PMID 12912715 · DOI 10.1001/archinte.163.15.1801Case-control studycited by the Tayebat archiveabstract checkedCurrent quinolone use was linked to about 4 times higher odds of Achilles rupture.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Link.
- How was the study done?
Case-control.
- How many people, animals or samples were studied?
1367 cases.
- What was actually found?
Higher risk.
- How large was the observed effect?
OR 4.3.
- What do the results mean in everyday life?
Known side effect.
- What are the study's limitations?
Observational.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
High.
-
Fluoroquinolones and aortic aneurysm (Taiwan)
Lee CC et al.. JAMA Intern Med 2015 · PMID 26436523 · DOI 10.1001/jamainternmed.2015.5389Case-control studycited by the Tayebat archiveabstract checkedCurrent use was linked to higher risk of rare aortic events.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Link.
- How was the study done?
Case-control.
- How many people, animals or samples were studied?
1477 cases.
- What was actually found?
Higher risk.
- How large was the observed effect?
RR 2.43.
- What do the results mean in everyday life?
Rare.
- What are the study's limitations?
Observational.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Moderate.
-
Fluoroquinolones and aortic aneurysm (Sweden)
Pasternak B et al.. BMJ 2018 · PMID 29519881 · DOI 10.1136/bmj.k678Cohort studycited by the Tayebat archiveabstract checkedAbout 82 extra cases per million treatment courses compared with amoxicillin.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Link.
- How was the study done?
Cohort.
- How many people, animals or samples were studied?
720,176 episodes.
- What was actually found?
Higher risk.
- How large was the observed effect?
HR 1.66; +82/million.
- What do the results mean in everyday life?
Rare.
- What are the study's limitations?
Observational.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
High.
-
Penicillin allergy label and resistant infections
Blumenthal KG et al.. BMJ 2018 · PMID 29950489 · DOI 10.1136/bmj.k2400Cohort studycited by the Tayebat archiveabstract checkedPeople labelled penicillin-allergic had more MRSA and C. difficile, partly due to alternative antibiotics.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Link.
- How was the study done?
Cohort.
- How many people, animals or samples were studied?
301,399.
- What was actually found?
Higher risk.
- How large was the observed effect?
aHR 1.69.
- What do the results mean in everyday life?
Allergy labels should be checked.
- What are the study's limitations?
Observational.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
High.
-
Fluoroquinolones raise tendon injury risk
Alves C et al.. Eur J Clin Pharmacol 2019 · PMID 31270563 · DOI 10.1007/s00228-019-02713-1Meta-analysisindependent cross-checkabstract checkedPooled studies show about 2.5-fold odds of Achilles tendon rupture.
Achilles rupture OR 2.52; tendinitis OR 3.95
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Pool tendon-injury data for fluoroquinolones
- How was the study done?
Meta-analysis
- How many people, animals or samples were studied?
15 studies
- What was actually found?
Higher risk of tendon injury
- How large was the observed effect?
OR 2.52 rupture
- What do the results mean in everyday life?
A real but rare side effect, higher in older people
- What are the study's limitations?
Heterogeneous observational studies
- What does it say about Elawady's specific claim?
Supports the claim
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Exact absolute risk
No study in this group is marked as key.
Studies contradicting or limiting the claim (2)
-
UK study finds no aortic risk from fluoroquinolones after fair comparison
Brown JP et al.. JAMA Cardiol 2023 · PMID 37585175 · DOI 10.1001/jamacardio.2023.2418Cohort studyindependent cross-checkabstract checked★ key studyCompared with other antibiotics, fluoroquinolones were not linked to aortic aneurysm or dissection.
Aortic: adjusted HR 1.03 vs cephalosporins; no association vs other antibiotics
Does the study support the specific claim? No · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Test aortic risk with fair comparisons
- How was the study done?
Cohort + case-crossover
- How many people, animals or samples were studied?
Over 3.5 million adults
- What was actually found?
No association after adjustment
- How large was the observed effect?
HR 1.03 (0.91-1.17)
- What do the results mean in everyday life?
Earlier alarms may reflect sicker patients
- What are the study's limitations?
Observational
- What does it say about Elawady's specific claim?
Contradicts the aortic part
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Risk in people with existing aneurysm
-
International study: no aortic risk from fluoroquinolones for urinary infections
Janetzki JL et al.. EClinicalMedicine 2025 · PMID 39975698 · DOI 10.1016/j.eclinm.2025.103096Cohort studyindependent cross-checkabstract checked★ key studyIn 13.6 million patients, fluoroquinolones did not raise aortic aneurysm/dissection risk versus other antibiotics.
Aortic: calibrated HR 0.91 vs TMP and 1.01 vs cephalosporins
Does the study support the specific claim? No · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Test aortic risk in UTI treatment
- How was the study done?
Network cohort
- How many people, animals or samples were studied?
13.6 million patients
- What was actually found?
No extra risk
- How large was the observed effect?
HR 0.91-1.01
- What do the results mean in everyday life?
The aortic warning may be overstated
- What are the study's limitations?
UTI only
- What does it say about Elawady's specific claim?
Contradicts the aortic part
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Risk for other uses
No study in this group is marked as key.
Studies with mixed or unclear results (0)
No studies in this group.
Regional context
Germany / EU
Data come partly from the UK and Sweden (see studies), so they are directly relevant to Europe.
Egypt
No Egyptian data were reviewed; the drug-specific risks apply wherever these antibiotics are used.
What applies in my country?
General scientific assessment
Mostly true Mostly correct: tendon and C. difficile harms are well documented; the aortic risk is uncertain after newer studies; all are drug-specific with low absolute risk.
This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.
References
- Meta-analysis of antibiotics and the risk of community-associated Clostridium difficile infection.. Brown KA et al.. Antimicrob Agents Chemother 2013 · PMID 23478961 · DOI 10.1128/AAC.02176-12
- Increased risk of achilles tendon rupture with quinolone antibacterial use, especially in elderly patients taking oral corticosteroids.. van der Linden PD et al.. Arch Intern Med 2003 · PMID 12912715 · DOI 10.1001/archinte.163.15.1801
- Risk of Aortic Dissection and Aortic Aneurysm in Patients Taking Oral Fluoroquinolone.. Lee CC et al.. JAMA Intern Med 2015 · PMID 26436523 · DOI 10.1001/jamainternmed.2015.5389
- Fluoroquinolone use and risk of aortic aneurysm and dissection: nationwide cohort study.. Pasternak B et al.. BMJ 2018 · PMID 29519881 · DOI 10.1136/bmj.k678
- Risk of meticillin resistant Staphylococcus aureus and Clostridium difficile in patients with a documented penicillin allergy: population based matched cohort study.. Blumenthal KG et al.. BMJ 2018 · PMID 29950489 · DOI 10.1136/bmj.k2400
- Fluoroquinolones and the risk of tendon injury: a systematic review and meta-analysis.. Alves C et al.. Eur J Clin Pharmacol 2019 · PMID 31270563 · DOI 10.1007/s00228-019-02713-1
- Association Between Fluoroquinolone Use and Hospitalization With Aortic Aneurysm or Aortic Dissection.. Brown JP et al.. JAMA Cardiol 2023 · PMID 37585175 · DOI 10.1001/jamacardio.2023.2418
- Risk of aortic aneurysm or dissection following use of fluoroquinolones: a retrospective multinational network cohort study.. Janetzki JL et al.. EClinicalMedicine 2025 · PMID 39975698 · DOI 10.1016/j.eclinm.2025.103096