Cephalexin Side Effects: Common, Serious & FDA Warnings
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Quick answer
Based on 21,000+ FDA adverse event reports, the most-reported cephalexin reactions include chronic kidney disease, renal failure, and acute kidney injury. FDA reports 8 active Class II recalls of cephalexin, primarily for failed dissolution specifications. The FDA-approved label does not carry a boxed warning.
For information only. MedivaScan summarizes public FDA data and is not medical advice. Consult a healthcare professional before changing any medication. If you experience a serious reaction, contact your doctor or call 911.
Common Side Effects of Cephalexin
The most-reported reactions in the FDA Adverse Event Reporting System (FAERS) for cephalexin. Percentages reflect the share of reports mentioning each reaction; a single report may include multiple reactions. Reports indicate co-occurrence, not causation.
| Reaction | Reports | % of total |
|---|---|---|
| Chronic Kidney Disease | 2,157 | 10.2% |
| Renal Failure | 1,558 | 7.4% |
| Acute Kidney Injury | 1,544 | 7.3% |
| Pain | 1,384 | 6.6% |
| Diarrhoea | 1,382 | 6.5% |
| Fatigue | 1,269 | 6.0% |
| Nausea | 1,262 | 6.0% |
| Dyspnoea | 1,192 | 5.6% |
| Anxiety | 1,144 | 5.4% |
| Headache | 1,121 | 5.3% |
Serious Outcomes and FDA Warnings
FAERS reports flagged with a serious outcome (death, hospitalization, life-threatening, disability, or congenital anomaly), plus reactions surfaced in the FDA-approved label's Warnings section. Reports indicate co-occurrence, not causation.
| Outcome flag | Reports | % of total |
|---|---|---|
| Serious reports (any flag) | — | — |
| Hospitalization | — | — |
From the FDA-approved label, Section 5.1: Hypersensitivity Reactions
Allergic reactions in the form of rash, urticaria, angioedema, anaphylaxis, erythema multiforme, Stevens-Johnson syndrome, or toxic epidermal necrolysis have been reported with the use of cephalexin. Before therapy with cephalexin is instituted, inquire whether the patient has a history of hypersensitivity reactions to cephalexin, cephalosporins, penicillins, or other drugs. Cross-hypersensitivity among beta-lactam antibacterial drugs may occur in up to 10% of patients with a history of penicillin allergy. If an allergic reaction to cephalexin occurs, discontinue the drug and institute appropriate treatment.
From the FDA-approved label, Section 5.4: Seizure Potential
Several cephalosporins have been implicated in triggering seizures, particularly in patients with renal impairment when the dosage was not reduced. If seizures occur, discontinue cephalexin. Anticonvulsant therapy can be given if clinically indicated.
Cephalexin Recalls
FDA enforcement actions matched to cephalexin via openFDA's structured generic_name field and the NDC bridge. Ongoing recalls are listed below (verify on FDA →); closed recalls are grouped in the disclosure that follows.
| Date | Reason | Class | Quantity | Status |
|---|---|---|---|---|
| 2025-06-18 | Failed Impurities/Degradation Specifications An out-of-specification result was observed in the related substance test at the sixth month of stability analysis. The individual impurity was identified to be Cephalexin Glucose Adduct. Ascend Laboratories, LLC | Class II | 48,936 - 100 mL bottles | Ongoing |
| 2025-06-18 | Failed Impurities/Degradation Specifications An out-of-specification result was observed in the related substance test at the sixth month of stability analysis. The individual impurity was identified to be Cephalexin Glucose Adduct. Ascend Laboratories, LLC | Class II | 10,620 - 200 mL bottles | Ongoing |
| 2024-06-12 | Labeling: Not Elsewhere Classified: Back label states Each contains: cephalexin monohydrate, USP equivalent to 2.5g' instead of Each Bottle contains: cephalexin monohydrate, USP equivalent to 5g Bryant Ranch Prepack, Inc. | Class III | 6 bottles | Ongoing |
| 2024-06-12 | Labeling: Not Elsewhere Classified: Back Label states 'Each contains: cephalexin monohydrate, USP equivalent to 5g' instead of Each Bottle contains: cephalexin monohydrate, USP equivalent to 10g' Bryant Ranch Prepack, Inc. | Class III | 61 Bottles | Ongoing |
| 2024-06-12 | Labeling: Not Elsewhere Classified: Front label states 100 Tablets instead of 100 ml and on the back label 'Each Tablet contains' instead of 'Each Bottle contains' No total dose per bottle listed should be 2.5 g' Bryant Ranch Prepack, Inc. | Class III | 156 bottles | Ongoing |
| 2024-06-12 | Labeling: Not Elsewhere Classified: Back Label states Each contains: cephalexin monohydrate, USP equivalent to 5g' on the back label instead of Each Bottle contains: cephalexin monohydrate, USP equivalent to 5g' Bryant Ranch Prepack, Inc. | Class III | 190 bottles | Ongoing |
| 2024-06-12 | Labeling: Not Elsewhere Classified: Back Label states 'Each contains: cephalexin monohydrate, USP equivalent to 5g' instead of Each Bottle contains: cephalexin monohydrate, USP equivalent to 10g' Bryant Ranch Prepack, Inc. | Class III | 104 bottles | Ongoing |
| 2021-05-05 | Failed Impurities/degradation specifications: Repackager recall due to Out of Specification detected by manufacturer for Individual Unidentified Impurity found during related substance test analysis of Cephalexin Preferred Pharmaceuticals, Inc. | Class II | Six bottles | Ongoing |
Show 9 closed recalls (2019 to 2021)
Includes resolved and terminated recalls matched to cephalexin. Most recent first.
| Date | Reason | Class | Quantity | Status |
|---|---|---|---|---|
| 2021-02-24 | CGMP Deviations: Individual Unidentified impurities results of the product was found at higher side of the specification limit. Ascend Laboratories LLC | Class II | 14,205 100 mL bottles | Terminated |
| 2021-02-24 | CGMP Deviations: Individual Unidentified impurities results of the product was found at higher side of the specification limit. Ascend Laboratories LLC | Class II | 23,436 200 mL bottles | Terminated |
| 2021-01-13 | Failed Impurity/Degradation Specifications: Unidentified impurities not complying with specifications were observed in various lots of Cephalexin FOS USP 125 mg/5 mL. Ascend Laboratories LLC | Class II | 20,232 bottles | Terminated |
| 2021-01-06 | Failed Impurity/Degradation Specifications Ascend Laboratories LLC | Class II | 29,317 bottles | Terminated |
| 2021-01-06 | Failed Impurity/Degradation Specifications Ascend Laboratories LLC | Class II | 9,524 bottles | Terminated |
| 2020-09-16 | Sub-Potent Drug: Out of specification test results for potency (below specification). Teva Pharmaceuticals USA | Class II | 38,487 bottles | Terminated |
| 2020-09-16 | CGMP deviations; there is a possibility that some bottles in these lots may have the active ingredient above and/or below specification limits. Teva Pharmaceuticals USA | Class II | 1,467,535 bottles | Terminated |
| 2020-09-16 | CGMP deviations; there is a possibility that some bottles in these lots may have the active ingredient above and/or below specification limits. Teva Pharmaceuticals USA | Class II | 103,940 bottles | Terminated |
| 2019-02-06 | CGMP Deviations; presence of extraneous material in the was observed in area that is between the primary package that is heat sealed and secondary packaging (poly-woven bag) of sucrose (an excipient) used in the finished product. Lupin Pharmaceuticals Inc. | Class II | 14,400 bottles | Terminated |
Cephalexin Shortages
FDA-listed shortages of cephalexin products. Strength and dosage-form level detail.
No active or recent shortages of cephalexin are listed. We refresh this view daily.
Is Cephalexin Safe?
Cephalexin is FDA-approved and the label does not carry a boxed warning. The label's Warnings and Precautions section covers hypersensitivity reactions (Section 5.1), clostridium difficile -associated diarrhea (Section 5.2), direct coombs’ test seroconversion positive direct (Section 5.3), seizure potential (Section 5.4), prolonged prothrombin time (Section 5.5), development of drug-resistant bacteria (Section 5.6).
As with any prescription, the assessment of safety is individual; consult a clinician about your own risk profile.
FDA-Approved Indications
Cephalexin is FDA-approved for use in the condition categories below. The FDA-approved label’s Indications and Usage section is shown verbatim.
Cephalexin capsules are a cephalosporin antibacterial drug indicated for the treatment of the following infections caused by susceptible isolates of designated bacteria: Respiratory tract infection ( 1.1 ) Otitis media ( 1.2 ) Skin and skin structure infections ( 1.3 ) Bone infections ( 1.4 ) Genitourinary tract infections ( 1.5 ) To reduce the development of drug-resistant bacteria and maintain the effectiveness of cephalexin capsules and other antibacterial drugs, cephalexin capsules should be used only to treat infections that are proven or strongly suspected to be caused by bacteria.Show full Indications and Usage
( 1.6 ) 1.1 Respiratory Tract Infections Cephalexin capsules are indicated for the treatment of respiratory tract infections caused by susceptible isolates of Streptococcus pneumoniae and Streptococcus pyogenes. 1.2 Otitis Media Cephalexin capsules are indicated for the treatment of otitis media caused by susceptible isolates of Streptococcus pneumoniae , Haemophilus influenzae , Staphylococcus aureus , Streptococcus pyogenes , and Moraxella catarrhalis. 1.3 Skin and Skin Structure Infections Cephalexin capsules are indicated for the treatment of skin and skin structure infections caused by susceptible isolates of the following Gram-positive bacteria: Staphylococcus aureus and Streptococcus pyogenes . 1.4 Bone Infections Cephalexin capsules are indicated for the treatment of bone infections caused by susceptible isolates of Staphylococcus aureus and Proteus mirabilis. 1.5 Genitourinary Tract Infections Cephalexin capsules are indicated for the treatment of genitourinary tract infections, including acute prostatitis, caused by susceptible isolates of Escherichia coli , Proteus mirabilis , and Klebsiella pneumoniae . 1.6 Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of cephalexin capsules and other antibacterial drugs, cephalexin capsules should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information is available, this information should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Frequently Asked Questions
What are the most-reported side effects of cephalexin?
Chronic kidney disease, renal failure, and acute kidney injury are among the most-reported reactions in FDA FAERS data for cephalexin. The full ranking, with reaction counts and the share of total reports, is in the Common Side Effects table above. Reports indicate co-occurrence, not causation; consult a clinician about your specific case.
Has cephalexin been recalled?
Yes. Cephalexin has active and closed recalls on record in the FDA enforcement database. Reasons are dominated by contamination or foreign material, mislabeling, and CGMP deviations. See the recalls table on this page for current counts, firm names, dates, and lot quantities.
What are cephalexin's current ongoing recalls about?
Active cephalexin recalls are listed in the recalls table above with their class, reason, firm, and affected lots. The dominant reasons across these recalls are mislabeling and contamination or foreign material. For lot numbers, distribution patterns, and the FDA enforcement record for any individual recall, follow the verify-on-FDA link from each row.
What do FDA recall classes mean?
Class I means a reasonable probability of serious adverse health consequences or death. Class II means temporary or medically reversible adverse health consequences with remote probability of serious harm. Class III means use of the product is unlikely to cause adverse health consequences. The class assignment is the FDA's, not the manufacturer's.
Data Sources & Methodology
How each section of this page is sourced, and how often the data is refreshed.
| Source | Endpoint | Refresh |
|---|---|---|
| FAERS reactions | openFDA /drug/event.json count API. Aggregated per drug per reaction term; we do not store individual reports. | Daily |
| Recalls | openFDA /drug/enforcement.json. Drugs matched via three confidence-tracked strategies: structured generic name (HIGH), NDC code bridge (MEDIUM), text token parse (LOW). Only HIGH and MEDIUM matches surface here. | 6 hours |
| Shortages | FDA Drug Shortages list. | Daily |
| Boxed warnings & label sections | openFDA /drug/label.json. Labels are stable; monthly cadence is sufficient. | Monthly |
| Condition categories | Synonym-mapped from drug_labels.indications. Methodology at /methodology/. | Per-drug |
What we do not do. We do not invent, paraphrase, or extrapolate drug claims. Every figure on this page comes from a query against an openFDA endpoint. If the data is unavailable, the section gracefully omits rather than filling the space with editorial guesswork.