Uses of CEPHALEXIN(ZYD) Tablet: - Bacterial infections Pneumonia, Otitis media, Bacterial endocarditis, Streptococcal pharyngitis, Cellulitis, Respiratory tract infections, Urinary tract infections, Bone and Joint Infections, Genitourinary tract infections, Acute prostatitis Hypersensitivity to cephalosporins.

First generation Cephalosporins

Cephalexin is a semisynthetic analogue of Cephalosporin C. It kills bacteria by interfering in the synthesis of the bacterial cell wall. Peptidoglycan is a heteropolymeric structure that provides the cell wall with mechanical stability. The final stage in the synthesis of peptidoglycan involves the completion of the cross-linking and the terminal glycine residue of the Pentaglycine Bridge is linked to the fourth residue of the pentapeptide (d-alanin). The transpeptidase enzyme that performs this step is inhibited by penicillins and cephalosporins. As a result the bacterial cell wall is weakened, the cell swells and then ruptures. Cephalexin is a first generation cephalosporin that is active by mouth.

How to use CEPHALEXIN(ZYD) Tablet: Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Cephalexin may be taken with or without food, but it is better to take it at a fixed time. Administration: May be taken with or without food. May be taken w/ meals to reduce GI discomfort. Adult Dose: Oral Bone and joint infections; Respiratory tract infections, Genitourinary Tract Infections, Otitis Media Adults 1 to 4 g/day in divided doses. Usual dose is 250 mg every 6 hours. Streptococcal pharyngitis, skin and skin structure infections, uncomplicated cystitis, cellulitis and mastitis >15 years 500 mg every 12 hours. Child Dose: Children 25 to 50 mg/kg/day q12h For streptococcal pharyngitis in patients >1year old and for skin and skin structure infections, divide total daily dose and give every 12 hours. In sever infections, 75–100 mg/kg/day for bone and joint, otitis media or severe infections q6–8h Beta-hemolytic streptococcal infections: Continue treatment for at least 10 days. Renal Dose: Renal impairment: CrCl (ml/min) 40-50 Max: 3 g daily. 10-40 Max: 1.5 g daily. <10 Max: 750 mg daily.

Concurrent use w/ metfromin may result to fatal lactic acidosis. May enhance the anticoagulant effect of vit K antagonists (e.g. warfarin). Increased risk of nephrotoxicity w/ potent diuretics (e.g. ethacrynic acid, furosemide) and other potentially nephrotoxic antibiotics (e.g. aminoglycosides, polymyxin, colistin). Prothrombin time may be prolonged when used concomitantly w/ oral anticoagulants. May reduce the effects of OCs. Hypokalaemia may result from concomitant use of cefalexin and cytotoxic drugs for leukaemia. Uricosuric drugs (e.g. probenecid) may suppress renal excretion, resulting to increased plasma levels of cefalexin. May diminish the therapeutic effect of Na picosulfate, BCG and typhoid vaccine. May reduce serum level w/ multivitamins/minerals.

Hypersensitivity to cephalosporins.

Common - Rash - Allergic reaction - Stomach pain - Nausea - Indigestion - Diarrhea GI disturbances (e.g. nausea, vomiting, diarrhoea, abdominal discomfort), dyspepsia; allergic reactions (e.g. rash urticaria, angioedema); genital and anal pruritus, genital candidiasis, vaginitis and vaginal discharge, dizziness, fatigue, headache, agitation, confusion, hallucinations, arthralgia, arthritis and joint disorders; eosinophilia, neutropenia, thrombocytopenia, haemolytic anaemia, slightly elevated AST and ALT. Rarely, erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis; cholestatic jaundice, transient hepatitis. Potentially Fatal: Anaphylactic reactions; nephrotoxicity.

Pregnancy Category B. Cefalexin may be used during pregnancy when it is considered essential. Cefalexin is found in the milk of nursing mothers, hence caution should be taken when it is administered to nursing mothers.

Precaution: Hypersensitivity to penicillins; pseudomembranous colitis; renal failure; pregnancy and lactation. Lactation: Drug excreted in breast milk; use with caution

Should be stored in cool and dry place.

First generation Cephalosporins

Cefalexin binds to one or more of the penicillin-binding proteins (PBPs) which inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell wall, thus inhibiting biosynthesis and arresting cell wall assembly resulting in bacterial cell death.

Pregnancy There are no adequate and well-controlled studies Available data from published epidemiologic studies and pharmacovigilance case reports over several decades with cephalosporin use, use in pregnant women have not established drug-associated risks of major birth defects, miscarriage, or adverse maternal or fetal outcomes Animal 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; estimated background risk of major birth defects and miscarriage for indicated population is unknown Lactation Data from a published clinical lactation study reports that cephalexin is present in human milk; relative infant dose (RID) is considered to be <1% of maternal weight adjusted dose; there are no data on effects of cephalexin on breastfed child or on milk production Development of health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed child from therapy or from underlying maternal condition