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Medication guide · Common after a work injury: Infection

Cephalexin: uses, appearance and warnings

What the official FDA label says Cephalexin is used for, what it looks like, and its most important warnings — in plain English, with the label text one click away.
Cephalosporin AntibacterialPrescription label

Uses

What the official label says Cephalexin is used for

The FDA label for Cephalexin states:

Cephalexin capsules USP is 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 USP and other antibacterial drugs, cephalexin capsules USP should be used only to treat infections that are proven or strongly suspected to be caused by bacte …
Read the label's “Indications and usage” section (verbatim)
Cephalexin capsules USP is 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 USP and other antibacterial drugs, cephalexin capsules USP 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 USP 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 USP 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 USP 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 USP 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 USP 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 USP and other antibacterial drugs, cephalexin capsules USP 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.

Names & forms

Brand names, forms and strengths

Brand names (from RxNorm; not every brand is still sold): Keflex, Rilexine.

Generic name: cephalexin · RxNorm ID (RxCUI): 2231

Forms and strengths of Cephalexin listed in RxNorm
FormStrengths listed in RxNorm
Chewable Tablet150 MG, 300 MG, 600 MG
Oral Capsule250 MG, 333 MG, 500 MG, 750 MG
Oral Solution25 MG/ML, 50 MG/ML
Oral Suspension25 MG/ML, 50 MG/ML, 100 MG/ML
Oral Tablet250 MG, 500 MG

Strengths are listed so you can recognise a product — not as dosing information. Only your prescriber can decide what is right for you.

Read the label's “Dosage forms and strengths” section (verbatim)
Capsules: 250 mg and 500 mg ( 3 ) 250 mg Capsules A white to yellowish-white granular powder filled into size "2" capsules (white and dark green) that are imprinted with "250" on dark green cap, and "LUPIN" on the white body in edible black ink. 500 mg Capsules A white to yellowish-white granular powder filled into size "0" capsules (light green and dark green) that are imprinted with "500" on the dark green cap, and "LUPIN" on the light green body in edible black ink.

Appearance

What Cephalexin looks like

Illustration: Dark Green Cap capsule capsule, imprint 250 LUPIN250 LUPIN

cephalexin 250 mg
Lupin Pharmaceuticals, Inc.

Illustration: Light Green Body and Dark Green Cap capsule capsule, imprint 500 LUPIN500 LUPIN

cephalexin 500 mg
Lupin Pharmaceuticals, Inc.

Illustration: white capsule capsule, imprint 801801

cephalexin 250 mg
AvKARE

Illustration: white capsule capsule, imprint 802802

cephalexin 500 mg
AvKARE

Illustration: light green cap and body capsule capsule, imprint 219219

cephalexin 500 mg
Ascend Laboratories, LLC

Illustration: Dark Green cap and body capsule capsule, imprint 220220

cephalexin 250 mg
Ascend Laboratories, LLC

Illustration based on label data — not a photo; appearance varies by manufacturer. Confirm with your pharmacist.
Appearance of Cephalexin products from DailyMed product data
StrengthFormColourShapeSizeImprintScoreLabeler
cephalexin 250 mgcapsulewhitegreen“Dark Green Cap”capsule18 mm250 · LUPIN1Lupin Pharmaceuticals, Inc.
cephalexin 500 mgcapsulegreen“Light Green Body and Dark Green Cap”capsule22 mm500 · LUPIN1Lupin Pharmaceuticals, Inc.
cephalexin 250 mgcapsulewhitecapsule22 mm8011AvKARE
cephalexin 500 mgcapsulewhitecapsule18 mm8021AvKARE
cephalexin 125 mg per 5 mLpowder, for suspensionwhite“Off-white to Light Pink”————Aurobindo Pharma Limited
cephalexin 250 mg per 5 mLpowder, for suspensionwhite“Off-white to Light Pink”————Aurobindo Pharma Limited
cephalexin 500 mgcapsulegreen“light green cap and body”capsule22 mm2191Ascend Laboratories, LLC
cephalexin 250 mgcapsulegreen“Dark Green cap and body”capsule18 mm2201Ascend Laboratories, LLC
cephalexin 333 mgcapsulegreen“LIGHT GREEN”capsule19 mmCEP · 3331Ascend Laboratories, LLC
cephalexin 750 mgcapsulegreen“DARK GREEN”capsule25 mmCEP · 7501Ascend Laboratories, LLC

From the product data in each manufacturer's label on DailyMed. Many companies make Cephalexin, so your medicine may look different from any shown here. If a pill looks unfamiliar, ask your pharmacist before taking it.

Read the label's “How supplied” section (verbatim)
Cephalexin capsules USP, are supplied as follows: 250 mg Capsules, Bottles of 100 NDC 68180-121-01 Bottles of 500 NDC 68180-121-02 500 mg Capsules, Bottles of 100 NDC 68180-122-01 Bottles of 500 NDC 68180-122-02 Cephalexin capsules USP should be stored at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Dispense in a tight, light-resistant container.

Safety

Important warnings for Cephalexin

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 ) Clostridioides difficile -Associated Diarrhea (CDAD) : Evaluate if diarrhea occurs. …

Contraindications — who should not use it (verbatim)
Patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs. ( 4 ) Cephalexin capsules are contraindicated in patients with known hypersensitivity to cephalexin or other members of the cephalosporin class of antibacterial drugs.
Warnings and precautions (verbatim excerpt)
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 ) Clostridioides 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 capsules 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 Clostridioides difficile -Associated Diarrhea Clostridioides 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. difficile produces toxins A and B, which contribute to the development of CDAD. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated. 5.3 Direct Coombs’ Test Seroconversion Positive direct Coombs' tests have been reported during treatment with the cephalosporin antibacterial drugs including cephalexin. Acute intravascular hemolysis induced by cephalexin therapy has been reported. If anemia develops during or after cephalexin therapy, perform a diagnostic work-up for drug-induced hemolytic anemia, discontinue cephalexin and institute appropriate therapy. 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. 5.5 Prolonged Prothrombin Time Cephalosporins may be associated with prolonged prothrombin time. Those at risk include patients with renal or hepatic impairment, or poor nutritional state, as well as patients receiving a protracted course of antibacterial therapy, and patients receiving anticoagulant therapy. Monitor prothrombin time in patients at risk and manage as indicated. 5.6 Development of Drug-Resistant Bacteria Prescribing cephalexin capsules in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria. Prolonged use of cephalexin may result in the overgrowth of nonsusceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.
Side effects — opening of the label's adverse reactions section
The most common adverse reactions associated with cephalexin include diarrhea, nausea, vomiting, dyspepsia and abdominal pain. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceuticals, Inc. at 1-800-399-2561 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. The following serious events are described in greater detail in the Warning and Precautions section: Hypersensitivity Reactions [see WARNING AND PRECAUTIONS ( 5.1 )] Clostridioides 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 )] Prolonged Prothrombin Time [see WARNINGS AND PRECAUTIONS ( 5.5 )] Development of Drug-Resistant Bacteria [see WARNINGS AND PRECAUTIONS ( 5.6 )] 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditio …
Drug interactions — opening of the label's section
Metformin: increased metformin concentrations. Monitor for hypoglycemia. ( 7.1 ) Probenecid: The renal excretion of cephalexin is inhibited by probenecid. Co-administration of probenecid with cephalexin is not recommended. ( 7.2 ) Administration of cephalexin may result in a false-positive reaction glucose in the urine. ( 7.3 ) 7.1 Metformin Administration of cephalexin with metformin results in increased plasma metformin concentrations and decreased renal clearance of metformin. Careful patient monitoring and dose adjustment of metformin is recommended in patients concomitantly taking cephalexin and metformin [see CLINICAL PHARMACOLOGY ( 12.3 ]. 7.2 Probenecid The renal excretion of cephalexin is inhibited by probenecid. Co-administration of probenecid with cephalexin capsules is not recommended. …

This is not a complete list of warnings or side effects. Read the full label and talk to your prescriber or pharmacist. To report a side effect to the FDA, use MedWatch.

Resources

If you were hurt at work

Whether a medicine is right for you is a decision for your prescriber. If you were injured on the job, these educational guides explain the next steps and who can help.

Sources

Label text is quoted from the Lupin Pharmaceuticals, Inc. label (label version effective August 24, 2026), retrieved October 20, 2026. Other manufacturers' labels for the same medicine may differ in wording.

If anything here differs from the label that came with your medicine, follow your label and your pharmacist.

Prescriptions.plus is an educational portal. We are not a pharmacy, law firm, medical provider, insurer or claims administrator, and nothing here is medical or legal advice. Educational purposes only. This page does not tell you whether to take a medicine or how much to take. Medical emergency? Call 911. Poison emergency: call Poison Control at 1-800-222-1222.