Cefalexin

0.65

logP = 0.65

CRYSTALS

WHITE TO OFF-WHITE, CRYSTALLINE POWDER

10mg/mL

SLIGHTLY SOL IN WATER; PRACTICALLY INSOL IN ALC, CHLOROFORM, ETHER

2.97e-01 g/L

326.8

326.8 °C

2.53

7.14

PKA: 5.2, 7.3

178.5 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

178.02 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]；182.19 Ų [M+K]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]；163.36 Ų [M+H-H2O]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]；182.91 Ų [M+Na]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

183.1 Ų [M+Na]+ [CCS Type: TW; Method: calibrated with Waters Major Mix]；186.9 Ų [M+H]+ [CCS Type: TW; Method: calibrated with Waters Major Mix]

179.56 Ų [M-H]-

Danger

H317 (100%): May cause an allergic skin reaction [Warning Sensitization, Skin]；H334 (100%): May cause allergy or asthma symptoms or breathing difficulties if inhaled [Danger Sensitization, respiratory]

P233, P260, P261, P271, P272, P280, P284, P302+P352, P304+P340, P321, P333+P317, P342+P316, P362+P364, P403, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 75 reports by companies from 5 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.；Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

5-Thia-1-azabicyclo4.2.0oct-2-ene-2-carboxylic acid, 7-(2R)-aminophenylacetylamino-3-methyl-8-oxo-, (6R,7R)-: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

Cephalexin: Does not have an individual approval but may be used under an appropriate group standard

IMAP assessments - 5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-[(aminophenylacetyl)amino]-3-methyl-8-oxo-, [6R-[6.alpha.,7.beta.(R*)]]-: Human health tier I assessment；IMAP assessments - 5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-[(aminophenylacetyl)amino]-3-methyl-8-oxo-, [6R-[6.alpha.,7.beta.(R*)]]-: Environment tier I assessment

Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

Cephalexin capsules, tablets, and powder for oral suspension should be stored in tight containers at a temperature less than 40 °C, preferably between 15-30 °C. After reconstitution, cephalexin oral suspensions should be stored at 2-8 °C and discarded if not used within 2 wk.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

PROBENECID IS EFFECTIVE IN SLOWING URINARY CLEARANCE & ENHANCING DURATION OF SYSTEMIC ANTIMICROBIAL ACTIVITY /OF CEPHALEXIN/.

...CEPHALOSPORINS...MAY BE AFFECTED BY CONCURRENT USE OF...SULFINPYRAZONE. DIMINISHED TUBULAR SECRETION...RESULT IN HIGHER & MORE SUSTAINED SERUM LEVELS & HENCE, INTENSIFICATION OF DRUG ACTIVITY. /CEPHALOSPORINS/

FUROSEMIDE MAY ENHANCE NEPHROTOXICITY OF CEPHALOSPORINS. /CEPHALOSPORINS/

Hypoprothrombinemia induced by large doses of salicylates and/or cephalosporins, and the gastrointestinal ulcerative or hemorrhagic potential of nonsteroidal anti-inflammatory drugs (NSAIDs), salicylates, or sulfinpyrazone may increase the risk of hemorrhage. /Cephalosporins/

For more Interactions (Complete) data for CEPHALEXIN (6 total), please visit the HSDB record page.

The adverse effects reported by drug manufacturers associated with cephalexin include abdominal pain, diarrhea, dyspepsia, gastritis, nausea, vomiting, erythema multiforme, genital pruritus, vaginitis, vaginal discharge, candidiasis, thrombocytopenia, neutropenia, eosinophilia, arthralgia, arthropathy, and arthritis.；Clinical trials have reported increased serum alanine aminotransferase, increased serum aspartate aminotransferase, cholestatic jaundice, and interstitial nephritis in patients using cephalexin.；Another aspect of cephalexin administration is the potential for allergic reactions to the drug. Patients who have been administered penicillin earlier may develop an allergy to cephalexin. These reactions occur when a patient's immune system generates IgG or IgM antibodies in response to penicillin, which can potentially bind to cephalexin when taken orally. The literature does not support the claim that about 10% of penicillin-allergic patients have cross-reactions to cephalosporin antibiotics. Retrospective studies suggest that the incidence of allergic or immunologic reactions to cephalosporins after the administration of penicillin is only around 1% to 3%.；Patients taking cephalexin have reported cases of Clostridioides difficile–associated diarrhea (CDAD) and colitis. Diarrhea can occur at the beginning of cephalexin administration and up to 3 months after treatment. Older individuals and those with compromised immune systems are at an increased risk of developing CDAD following long-term antibiotic treatments.；Immunogenic hemolytic anemia, although rare, has been reported, particularly in patients with hypersensitivity reactions to other cephalosporins. Other hypersensitivity reactions that have been reported include skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug rash with eosinophilia and systemic symptoms. Although cephalexin generally has few adverse effects, rare occurrences of toxic tendinopathy have been reported. Moreover, a clinical case study has documented other rare adverse effects of cephalexin, such as drug-induced acute generalized exanthematous pustulosis.；Drug Interactions；Like many other medications, cephalexin can interact with other drugs, potentially affecting their efficacy or safety. Therefore, it is essential to be aware of potential drug interactions when prescribing or administering cephalexin to ensure optimal patient outcomes.；* Metformin: Coadministration of cephalexin with metformin may result in increased plasma concentration and decreased renal clearance of metformin. Close monitoring of patients is advised, and adjustments to the metformin dose may be necessary when cephalexin and metformin are administered together.；* Probenecid: Coadministration of cephalexin with probenecid is not recommended as it may inhibit the renal excretion of cephalexin. Studies have shown that probenecid can extend and flatten the plasma concentration–time curve of cephalexin, thereby increasing the likelihood of achieving optimal pharmacokinetic and pharmacodynamic targets. However, the simultaneous use of cephalexin and probenecid may benefit specific patient populations.

Cephalexin is associated with a relatively low incidence of adverse effects in patients when the drug is administered correctly and safely. However, in cases of toxicity or overdose, adverse effects may include soreness of the oral cavity, pruritus of pregnancy, and gastrointestinal symptoms such as nausea, vomiting, epigastric distress, diarrhea, and hematuria. Furthermore, there have been only a few sporadic documented cases of cephalexin leading to fatal episodes of Stevens-Johnson syndrome and toxic epidermal necrolysis.；In the event of an overdose, it is advisable to implement general supportive measures. However, the effectiveness of interventions such as charcoal hemoperfusion, forced diuresis, peritoneal dialysis, and hemodialysis in treating cephalexin overdose has not been established yet. To obtain the most up-to-date protocol for managing cephalexin overdose, it is recommended to contact the local drug poison center.

NEUROTOXICITY, SUCH AS HEADACHE, TINNITUS, ATAXIA, & DIPLOPIA, SOMETIMES DEVELOP; THESE EFFECTS ARE REVERSIBLE. CHANGES IN INTESTINAL & VAGINAL FLORA MAY OCCUR; MONILIASIS IS OCCASIONAL, & OVER GROWTH BY PS AERUGINOSA HAS BEEN REPORTED.

ABOUT 5% OF PATIENTS RECEIVING...SEMISYNTHETIC CEPHALOSPORINS DEVELOP HYPERSENSITIVITY REACTIONS, INCL FEVER, EOSINOPHILIA, SERUM SICKNESS, URTICARIAL OR MORBILLIFORM RASHES, OR ANAPHYLAXIS. TRANSIENT NEUTROPENIA HAS BEEN OBSERVED... /CEPHALOSPORINS/

...CEPHALEXIN, ORALLY ADMIN CEPHALOSPORINS, OCCASIONALLY PRODUCE NAUSEA, VOMITING, & DIARRHEA.

DIRECT POSITIVE COOMBS REACTION IS FREQUENTLY (40%) NOTED WHEN LARGE DOSES OF...CEPHALOSPORINS ARE ADMIN OR WHEN CONVENTIONAL DOSES ARE GIVEN IN PRESENCE OF RENAL DYSFUNCTION. /CEPHALOSPORINS/

For more Human Toxicity Excerpts (Complete) data for CEPHALEXIN (35 total), please visit the HSDB record page.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Cephalexin

vLess-DILI-concern

4

Adverse reactions

DOI:10.1016/j.drudis.2016.02.015

◉ Summary of Use during Lactation；Limited information indicates that maternal cephalexin produces low levels in milk that are usually not expected to cause adverse effects in breastfed infants. Cephalexin is an alternative for the treatment of mastitis. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with cephalosporins, but these effects have not been adequately evaluated. A rare case of a severe allergic reaction occurred in an infant previously exposed to intravenous cefazolin whose mother began taking cephalexin while breastfeeding. Cephalexin is acceptable in nursing mothers.；◉ Effects in Breastfed Infants；In a prospective follow-up study, 7 nursing mothers reported taking cephalexin (dosage not specified). Two mothers reported diarrhea in their infants. No rashes or candidiasis were reported among the exposed infants.；A prospective, controlled study asked mothers who called an information service about adverse reactions experience by their breastfed infants. One of 11 cephalexin-exposed infants reportedly developed diarrhea during maternal cephalexin therapy.；A woman received intravenous cephalothin 1 g every 6 hours for 3 days. Her breastfed infant had a green liquid stool, severe diarrhea, discomfort and crying. The mother's drug regimen was then changed to oral cephalexin 500 mg plus oral probenecid 500 mg 4 times daily for another 16 days. The infant continued to have diarrhea during this time. The authors rated the diarrhea as probably related to cephalexin in milk.；A 4-month-old infant was treated with intravenous cefazolin for a urinary tract infection. Nine days after being discharged and cefazolin discontinuation, the infant developed a blistering rash over most of the body that was diagnosed as toxic epidermal necrolysis (TEN). The infant was being breastfed (extent unspecified) by his mother who had begun cephalexin 2 days prior to the onset of symptoms. A lymphocyte transformation test performed 4 weeks after treatment for TEN was completed found sensitization to both cefazolin and cephalexin. The infant's reaction was probably caused by cephalexin in breastmilk after initial sensitization and subsequent cross-reaction to cefazolin.；◉ Effects on Lactation and Breastmilk；Relevant published information was not found as of the revision date.

◈ What is cephalexin?；Cephalexin is an antibiotic medication that has been used to treat infections such as Staphylococcus aureus (Staph) and Escherichia coli (E. coli). Some brand names for cephalexin are Keflex® and Keftab®.Sometimes when people find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy.Having certain infections (such as a Staph or E. coli infection )during pregnancy can increase the chance for pregnancy-related problems or infections in a newborn baby. MotherToBaby has fact sheets on Staph and E. coli infections here: https://mothertobaby.org/fact-sheets/staphylococcus-aureus-pregnancy/ and https://mothertobaby.org/fact-sheets/e-coli-pregnancy/.；◈ I take cephalexin. Can it make it harder for me to get pregnant?；Studies have not been done in humans to see if cephalexin can make it harder to get pregnant. In animal studies, cephalexin did not affect fertility (ability to get pregnant).；◈ Does taking cephalexin increase the chance of miscarriage?；Miscarriage is common and can occur in any pregnancy for many different reasons. In a study of 262 people who took cephalexin during pregnancy, there was no increase in miscarriages compared to a similar group of people who did not take cephalexin.；◈ Does taking cephalexin increase the chance of birth defects?；Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Information on the use of cephalexin in pregnancy is limited. In a study of 262 people who took cephalexin during pregnancy, there was no increased chance for birth defects above the background risk.；◈ Does taking cephalexin in pregnancy increase the chance of other pregnancy-related problems?；Studies have not been done to see if cephalexin increases the chance for pregnancy-related problems such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).；◈ Does taking cephalexin in pregnancy affect future behavior or learning for the child?；Studies have not been done to see if cephalexin can cause behavior or learning issues for the child.；◈ Breastfeeding while taking cephalexin:；Cephalexin gets into breast milk in small amounts. In reports of 20 babies exposed to cephalexin through breast milk, 4 had diarrhea. There is one report of a baby getting a rash after being breastfed, due to a sensitivity to cephalexin. If you suspect the baby has any symptoms (such as diarrhea or rash), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.；◈ If a male takes cephalexin, could it affect fertility or increase the chance of birth defects?；Studies have not been done to see if cephalexin could affect male fertility (ability to get partner pregnant) or increase the chance of birth defects above the background risk. Some infections, such as Staph or E.coli, might affect male fertility. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

LD50 MOUSE ORAL 1.6-4.5 G/KG /MONOHYDRATE/

LD50 MOUSE INTRAPERITONEAL 0.4-1.3 G/KG /MONOHYDRATE/

LD50 RAT ORAL GREATER THAN 5.0 G/KG /MONOHYDRATE/

LD50 RAT INTRAPERITONEAL GREATER THAN 3.7 G/KG /MONOHYDRATE/

5-Thia-1-azabicyclo4.2.0oct-2-ene-2-carboxylic acid, 7-(2R)-aminophenylacetylamino-3-methyl-8-oxo-, (6R,7R)-: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

Cephalexin: Does not have an individual approval but may be used under an appropriate group standard

Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

J01DB01

J - Antiinfectives for systemic use；J01 - Antibacterials for systemic use；J01D - Other beta-lactam antibacterials；J01DB - First-generation cephalosporins；J01DB01 - Cefalexin

QJ - Antiinfectives for systemic use；QJ51 - Antibacterials for intramammary use；QJ51D - Other beta-lactam antibacterials for intramammary use；QJ51DB - First-generation cephalosporins；QJ51DB01 - Cefalexin

QJ - Antiinfectives for systemic use；QJ01 - Antibacterials for systemic use；QJ01D - Other beta-lactam antibacterials；QJ01DB - First-generation cephalosporins；QJ01DB01 - Cefalexin

J01DB01

Cephalexin (also called Cefalexin) is a first generation cephalosporin antibiotic. It is one of the most widely prescribed antibiotics, often used for the treatment of superficial infections that result as complications of minor wounds or lacerations. It is effective against most gram-positive bacteria through its inihibition of the cross linking reaction between N-acetyl muramicacid and N-acetylglucosamine in the cell wall, leading to cell lysis.

Cephalexin is a first generation cephalosporin antibiotic. Cephalosporins contain a beta lactam and dihydrothiazide. Unlike penicillins, cephalosprins are more resistant to the action of beta lactamase. Cephalexin inhibits bacterial cell wall synthesis, leading breakdown and eventualy cell death.

CEPHALOTHIN & ITS CONGENERS INHIBIT BACTERIAL CELL-WALL SYNTHESIS IN MANNER SIMILAR TO THAT OF PENICILLIN. /CEPHALOSPORINS/

The penicillins and their metabolites are potent immunogens because of their ability to combine with proteins and act as haptens for acute antibody-mediated reactions. The most frequent (about 95 percent) or "major" determinant of penicillin allergy is the penicilloyl determinant produced by opening the beta-lactam ring of the penicillin. This allows linkage of the penicillin to protein at the amide group. "Minor" determinants (less frequent) are the other metabolites formed, including native penicillin and penicilloic acids. /Penicillins/

Bactericidal; action depends on ability to reach and bind penicillin-binding proteins located in bacterial cytoplasmic membranes; cephalosporins inhibit bacterial septum and cell wall synthesis, probably by acylation of membrane-bound transpeptidase enzymes. This prevents cross-linkage of peptidoglycan chains, which is necessary for bacterial cell wall strength and rigidity. Also, cell division and growth are inhibited, and lysis and elongation of susceptible bacteria frequently occur. Rapidly dividing bacteria are those most susceptible to the action of cephalosporins. /Cephalosporins/

CEPHALOSPORIN C IS VERY RESISTANT TO ACTION OF PENICILLINASE, FOR WHICH IT IS BOTH COMPETITIVE & NONCOMPETITIVE INHIBITOR, DEPENDING ON SUBSTRATE TESTED... /CEPHALOSPORINS/

The half life of cephalexin is 49.5 minutes in a fasted state and 76.5 minutes with food though these times were not significantly different in the study.

LESS THAN 10 TO 15%...IS BOUND TO PLASMA PROTEIN, & PLASMA DRUG CONCN FALL RAPIDLY, T/2 OF CEPHALEXIN NORMALLY BEING ABOUT 40 MIN.

/IN RATS/ RATIOS OF BONE TO SERUM CONCN AVG...1:9 FOR CEPHALEXIN DURING 0.25-4 HR AFTER /ORAL/ DOSING. DESPITE DIFFERENCES IN CONCN; T/2 IN BONE & SERUM WERE SIMILAR.

PEAK TIME, T/2 OF ELIMINATION, T/2 OF ABSORPTION, & VOL OF DISTRIBUTION WERE ALL SIMILAR FOLOWING ADMIN OF EITHER 1 OR 2 G OF CEPHALEXIN.

The serum half-life of cephalexin is 0.5-1.2 hr in adults with normal renal function. The serum half-life of the drug is reported to be about 5 hr in neonates and 2.5 hr in children 3-12 mo of age. In one study, the serum half-life was 7.7 hr in adults with creatinine clearances of 9.2 ml/min and 13.9 hr in adults with creatinine clearances of 4 ml/min.

5SFF1W6677

CEPHALEXIN ANHYDROUS

Established Pharmacologic Class [EPC] - Cephalosporin Antibacterial

Chemical Structure [CS] - Cephalosporins

Cephalexin anhydrous is a Cephalosporin Antibacterial.

CEPHALEXIN

Well absorbed from the upper gastrointestinal tract with nearly 100% oral bioavailability. Cephalexin is not absorbed in the stomach but is absorbed in the upper intestine. Patients taking 250mg of cephalexin reach a maximum plasma concentration of 7.7mcg/mL and patients taking 500mg reach 12.3mcg/mL.

Cephalexin is over 90% excreted in the urine after 6 hours by glomerular filtration and tubular secretion with a mean urinary recovery of 99.3%. Cephalexin is unchanged in the urine.

5.2-5.8L.

Clearance from one subject was 376mL/min.

LESS THAN 10 TO 15%...IS BOUND TO PLASMA PROTEIN, & PLASMA DRUG CONCN FALL RAPIDLY... MORE THAN 90%...IS EXCRETED UNALTERED IN URINE WITHIN 6 HR, PRIMARILY BY RENAL TUBULAR SECRETION. ...THERAPEUTICALLY EFFECTIVE CONCN ARE STILL ACHIEVED IN URINE OF PT WITH DECR RENAL FUNCTION.

CEPHALEXIN...IS WELL ABSORBED FROM GI TRACT. PEAK PLASMA CONCN, REACHED @ ABOUT 1 HR AFTER INGESTION OF DRUG, ARE APPROX 9 & 18 UG/ML AFTER ORAL DOSES OF 250 & 500 MG, RESPECTIVELY. INGESTION OF FOOD MAY DELAY ABSORPTION.

ANTIBIOTIC FOR INFECTIONS OF THE RESPIRATORY & GENITOURINARY TRACTS & OF THE SKIN, EYE, & BONE; ANTIBIOTIC FOR VETERINARY USE

MEDICATION

MEDICATION (VET):

Use (kg; approx.) in Germany (2009): >1000；Use (kg; exact) in Germany (2009): 2020；Use (kg) in USA (2002): 148000；Consumption (g per capita; approx.) in Germany (2009): 0.0122；Consumption (g per capita; exact) in Germany (2009): 0.0247；Consumption (g per capita) in the USA (2002): 0.525；Excretion rate: 0.8；Calculated removal (%): 22

(1977) PROBABLY GREATER THAN 4.54X10+5 GRAMS

(1979) PROBABLY GREATER THAN 4.54X10+5 GRAMS

ACYLATION OF 7-AMINO-3-METHYL-8-OXO-5-THIA-1-AZABICYCLO[4.2.0]OCT-2-ENE-2-CARBOXYLIC ACID (PREPARED FROM CEPHALOSPORIN C) WITH 2-PHENYLGLYCINE IN AN APPROPRIATE DEHYDRATING ENVIRONMENT

7-AMINO-3-METHYL-8-OXO-5-THIA-1-AZABICYCLO[4.2.0]OCT-2-ENE-2-CARBOXYLIC ACID, WHICH MAY BE PREPD FROM NATURAL ANTIBIOTIC CEPHALOSPORIN C, IS ACYLATED WITH 2-PHENYLGLYCINE IN APPROPRIATE DEHYDRATING ENVIRONMENT.

Animal Drugs -> FDA Approved Animal Drug Products (Green Book) -> Active Ingredients

Pharmaceuticals -> Animal Drugs -> Approved in Taiwan

RYAN, ET AL, J MED CHEM 12, 310 (1969); MORIN, JACKSON, US PATENT 3,275,626 (1966 TO LILLY)

.../CEPHALEXIN/ SEMISYNTHETIC DERIVATIVE OF CEPHALOSPORIN C.