pharmacopeia
GET
/api/v1/drug/cephalexin
2D structure
(6R,7R)-7-[[(2R)-2-amino-2-phenylacetyl]amino]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid
SMILES CC1=C(N2[C@@H]([C@@H](C2=O)NC(=O)[C@@H](C3=CC=CC=C3)N)SC1)C(=O)O
InChIKey ZAIPMKNFIOOWCQ-UEKVPHQBSA-N

Mechanism of action

Sourced from openFDA

Cephalexin is a cephalosporin antibacterial drug [see Microbiology (12.4) ] .

Enzyme

Indications

Sourced from openFDA
  • 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. ( 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.ICD-10: H66.90

Contraindications

Sourced from openFDA
  • Cephalexin capsules are contraindicated in patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs. Patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs.contraindicated

Dosage & administration

Sourced from openFDA

Adults and patients at least 15 years of age The usual dose is 250 mg every 6 hours, but a dose of 500 mg every 12 hours may be administered ( 2.1 ) Pediatric patients (over 1 year of age) Otitis media: 75 to 100 mg/kg in equally divided doses every 6 hours ( 2.2 ) All other indications: 25 to 50 mg/kg given in equally divided doses ( 2.2 ) In severe infections: 50 to 100 mg/kg may be administered in equally divided doses ( 2.2 ) Duration of therapy ranges from 7 to 14 days depending on the infection type and severity. ( 2 ) Dosage adjustment is required in patients with severe and end stage renal disease (ESRD) defined as creatinine clearance below 30 mL/min. ( 2.3 ) 2.1 Adults and Pediatric Patients at Least 15 Years of Age The usual dose of oral cephalexin capsules is 250 mg every 6 hours, but a dose of 500 mg every 12 hours may be administered. Treatment is administered for 7 to 14 days. For more severe infections larger doses of oral cephalexin capsules may be needed, up to 4 grams daily in two to four equally divided doses. 2.2 Pediatric Patients (over 1 year of age) The recommended total daily dose of oral cephalexin capsules for pediatric patients is 25 to 50 mg/kg given in equally divided doses for 7 to 14 days. In the treatment of β-hemolytic streptococcal infections, duration of at least 10 days is recommended. In severe infections, a total daily dose of 50 to 100 mg/kg may be administered in equally divided doses. For the treatment of otitis media, the recommended daily dose is 75 to 100 mg/kg given in equally divided doses.

Warnings & precautions

Sourced from openFDA

Serious hypersensitivity (anaphylactic) reactions : Prior to use, inquire regarding history of hypersensitivity to beta-lactam antibacterial drugs. Discontinue the drug if signs or symptoms of an allergic reaction occur and institute supportive measures. ( 5.1 ) Clostridium difficile -associated diarrhea (CDAD ): Evaluate if diarrhea occurs. ( 5.2 ) Direct Coombs’ Test Seroconversion : If anemia develops during or after cephalexin therapy, evaluate for drug-induced hemolytic anemia. ( 5.3 ) Seizure Potential : Use lower dose in patients with renal impairment. ( 5.4 ) 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. 5.2 Clostridium difficile -Associated Diarrhea Clostridium difficile - associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including cephalexin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C.

Adverse reactions

Sourced from openFDA

The following serious events are described in greater detail in the Warning and Precautions section: Hypersensitivity reactions [see Warning and Precautions (5.1) ] Clostridium difficile -associated diarrhea [see Warnings and Precautions (5.2) ] Direct Coombs’ Test Seroconversion [see Warnings and Precautions (5.3) ] Seizure Potential [see Warnings and Precautions (5.4) ] Effect on Prothrombin Activity [see Warnings and Precautions (5.5) ] Development of Drug-Resistant Bacteria [see Warnings and Precautions (5.6) ] The most common adverse reactions associated with cephalexin include diarrhea, nausea, vomiting, dyspepsia and abdominal pain . ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In clinical trials, the most frequent adverse reaction was diarrhea. Nausea and vomiting, dyspepsia, gastritis, and abdominal pain have also occurred. As with penicillins and other cephalosporins, transient hepatitis and cholestatic jaundice have been reported.

Use in specific populations

Sourced from openFDA

Renal Impairment: Monitor patients longer for toxicity and drug interactions due to delayed clearance. (8.6) 8.1 Pregnancy Risk Summary Available data from published epidemiologic studies and pharmacovigilance case reports over several decades with cephalosporin use, including cephalexin use in pregnant women have not established drug-associated risks of major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data) . Animal reproduction studies with mice and rats using oral doses of cephalexin that are 0.6- and 1.2-times the maximum recommended human dose (MRHD) based on body surface area during organogenesis revealed no evidence of harm to the fetus (see Data). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Pharmacokinetics

Sourced from openFDA
Metabolism
Absorption: Cephalexin is acid stable and may be given without regard to meals. Following doses of 250 mg, 500 mg, and 1 g, average peak serum levels of approximately 9, 18, and 32 mcg/mL, respectively, were obtained at 1 hour.

Overdosage

Sourced from openFDA

Symptoms of oral overdose may include nausea, vomiting, epigastric distress, diarrhea, and hematuria. In the event of an overdose, institute general supportive measures. Forced diuresis, peritoneal dialysis, hemodialysis, or charcoal hemoperfusion have not been established as beneficial for an overdose of cephalexin.

Approval history

Sourced from openFDA
  • Feb 13, 1987ANDAANDA062702Teva
  • Feb 13, 1987ANDAANDA062703Teva
  • Jan 12, 1989ANDAANDA063024Teva
  • Feb 24, 2005ANDAANDA065152Chartwell Rx
  • Aug 17, 2005ANDAANDA065234Lupin
  • Nov 16, 2005ANDAANDA065253Aurobindo Pharma
  • Nov 25, 2005ANDAANDA065229Lupin
  • Jul 25, 2007ANDAANDA065336Yung Shin Pharm

FAERS reports

View JSON
Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
21,106 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Chronic Kidney Disease2,15710%
  2. 2Renal Failure1,5587.4%
  3. 3Acute Kidney Injury1,5447.3%
  4. 4Pain1,3856.6%
  5. 5Diarrhoea1,3836.6%
  6. 6Fatigue1,2716.0%
  7. 7Nausea1,2626.0%
  8. 8Dyspnoea1,1935.7%
  9. 9Anxiety1,1445.4%
  10. 10Rash1,1285.3%
  11. 11Headache1,1215.3%
  12. 12Drug Ineffective1,0224.8%
  13. 13Off Label Use8944.2%
  14. 14Vomiting8544.0%
  15. 15Dizziness8514.0%

Literature

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Recent PubMed references pinned to Cephalexin as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 115 ClinicalTrials.gov registrations naming Cephalexin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Structural analogs

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Ranked by 2D fingerprint (Tanimoto) similarity over PubChem structures. Structural proximity only — not a claim of therapeutic equivalence.

Frequently asked questions

How does Cephalexin work?
Cephalexin is a cephalosporin antibacterial drug [see Microbiology (12.4) ] .
What is Cephalexin used for?
According to FDA labeling, Cephalexin carries indications including: 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. ( 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.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Cephalexin?
Cephalexin is classified as First-generation cephalosporins, Enzyme Inhibitors, Decreased Cell Wall Synthesis & Repair.
What are the brand names for Cephalexin?
Cephalexin is marketed under brand names including Keflex, Rilexine.
What are the contraindications for Cephalexin?
Cephalexin labeling lists contraindications including: Cephalexin capsules are contraindicated in patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs. Patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs.. Always consult the full prescribing information and a clinician.
Note. Data for cephalexin is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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