Cephalexin oral suspension, USP is a semisynthetic cephalosporin antibacterial drug intended for oral administration. It is 7-(D-α- Amino-α-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid monohydrate. Cephalexin has the molecular formula C 16 H 17 N 3 O 4 S•H 2 O and the molecular weight is 365.41. Cephalexin has the following structural formula: Inactive Ingredients : Colloidal silicon dioxide, FD&C Red # 40, methyl cellulose (15 premium LV), methyl cellulose (4AC premium), sodium benzoate, strawberry flavor, sucrose, xanthan gum. cepha-structure

What kind of drug is cephalexin?

The FDA classifies cephalexin as a cephalosporin antibacterial. Cephalosporins kill bacteria by blocking the proteins they use to build their cell walls. Without an intact wall, the bacterium cannot hold its shape and dies, which clears the infection. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

Can you take cephalexin with other medicines?

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run cephalexin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

What brand names is cephalexin sold under?

We track 4 cephalexin-containing products in the U.S.: Cephalexin, Keflet, Keflex and Keftab. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

What forms does cephalexin come in?

Across the brands we track, cephalexin is currently marketed as capsule, powder and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Is there a generic cephalexin?

Yes. Our catalog lists 1 generic cephalexin product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

Has cephalexin been recalled?

The FDA's Enforcement database lists at least 5 recall records whose product description mentions cephalexin. The most recent: Cephalexin for Oral Suspension (May 23, 2025). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.

Cephalexin: uses, dosing, side effects & brands

Cephalexin is a cephalosporin antibacterial sold in the U.S. under 4 brand and generic names, for human bites, infectious bone diseases and escherichia coli infections. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.

By the pharmaranks editorial teamReviewed against the FDA (openFDA label, NDC Directory & Enforcement) sourcesHow we research

Key facts

Drug class: Cephalosporin Antibacterial
Treats: Human Bites, Infectious Bone Diseases and Escherichia Coli Infections
Available as: Capsule · Powder · Tablet
Sold as: 4 products — Cephalexin, Keflet and Keflex, and others
Prescription?: Prescription only
Generic available?: Yes
Typical price: about $0 for a 30-count supply

How cephalexin is dosed

From the FDA label for Keflet (application NDA050440). Other cephalexin products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.

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 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 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 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…

Cephalexin side effects

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. To report SUSPECTED ADVERSE REACTIONS, contact Ascend Laboratories, LLC at 1-877-ASC--RX01 (877-272-7901) 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. Other reactions have…

Every cephalexin product we track (4)

Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.

Cephalexin products
#	Drug	Rating	Type	Form	Generic?	Typical price
1	Cephalexin	Not yet rated	Prescription	Capsule	Generic	$0	View →
2	Keflet	Not yet rated	Prescription	Tablet	Generic	$0	View →

What cephalexin pills look like

Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.

Cephalexin pill imprints
Imprint	Strength	Colour	Shape	Maker
219	500 mg	green	capsule	—
219	500 mg	green	capsule	—
219	500 mg	green	capsule	—
220	250 mg	green	capsule	—
CEP;333	333 mg	green	capsule	—
CEP;750	750 mg

Cephalexin recalls

From the FDA Enforcement database. A recall covers specific lots — not the drug as a whole.

Frequently asked questions

What is cephalexin?: Cephalexin oral suspension, USP is a semisynthetic cephalosporin antibacterial drug intended for oral administration. It is 7-(D-α- Amino-α-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid monohydrate. Cephalexin has the molecular formula C 16 H 17 N 3 O 4 S•H 2 O and the molecular weight is 365.41. Cephalexin has the following structural formula: Inactive Ingredients : Colloidal silicon dioxide, FD&C Red # 40, methyl cellulose (15 premium LV), methyl cellulose (4AC premium), sodium benzoate, strawberry flavor, sucrose, xanthan gum. cepha-structure
What kind of drug is cephalexin?: The FDA classifies cephalexin as a cephalosporin antibacterial. Cephalosporins kill bacteria by blocking the proteins they use to build their cell walls. Without an intact wall, the bacterium cannot hold its shape and dies, which clears the infection. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take cephalexin with other medicines?: It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run cephalexin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is cephalexin sold under?: We track 4 cephalexin-containing products in the U.S.: Cephalexin, Keflet, Keflex and Keftab. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does cephalexin come in?: Across the brands we track, cephalexin is currently marketed as capsule, powder and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.