Keflex
GENERAL
Food does not affect absorption significantly
Half-life: 0.5 to 2 hours
Excretion:
-Urine: Approximately 80% to 90% excreted as parent drug within 6 to 8 hoursFirst-generation cephalosporin
Report any loose stool/diarrhea w/in 2mo of taking keflex
Category B pregnancy
Half-life: 0.5 to 2 hours
Excretion:
-Urine: Approximately 80% to 90% excreted as parent drug within 6 to 8 hoursFirst-generation cephalosporin
Report any loose stool/diarrhea w/in 2mo of taking keflex
Category B pregnancy
SUSCEPTIBILITIES
G+ bacteria skin infection
UTI from E.coli, Proteus, Klebsiella, MSSA, also Streptococci Grp A,B,C,G, Strep Viridans, S. pneumoniae, H. influenzae
UTI from E.coli, Proteus, Klebsiella, MSSA, also Streptococci Grp A,B,C,G, Strep Viridans, S. pneumoniae, H. influenzae
MONITORING
Prothrombin time if at high risk, renal function if CKD
MECHANISM
Bactericidal via bacterial cell wall synthesis inhibition by binding to penicillin binding proteins
MEDICATION INTERACTIONS
coNTRAINDICATIONS
History of major allergy to penicillins (AU)
Patients with porphyria (UK-some oral suspensions)
Patients with porphyria (UK-some oral suspensions)
WARNINGS/PRECAUTIONS
C. diff reported with nearly all ABX
Reports of drug induced acute intravascular hemolysis
Can cause positive direct Coomb's test
May prolong prothrombin time
May cause allergic reaction (rash, Steven's Johnson's syndrome)
Possible cross reactivity with penicillin allergies
May induce acute porphyria crisis
Possibly lowers seizure threshold, especially if reduced renal function
OK for breastfeeding, but does pass into breast milk and are reports of diarrhea and thrush in infants breastfeeding
Reports of drug induced acute intravascular hemolysis
Can cause positive direct Coomb's test
May prolong prothrombin time
May cause allergic reaction (rash, Steven's Johnson's syndrome)
Possible cross reactivity with penicillin allergies
May induce acute porphyria crisis
Possibly lowers seizure threshold, especially if reduced renal function
OK for breastfeeding, but does pass into breast milk and are reports of diarrhea and thrush in infants breastfeeding
SIDE EFFECTS
The most commonly reported side effects included diarrhea, dyspepsia, gastritis, nausea, and vomiting.
Other reported side effects include anal pruritis, some bone marrow suppression, rash, Steven's Johnson syndrome, hepatitis, elevated LFT's, genital pruritus, genital candidiasis, vulvovaginitis/vaginitis and vaginal discharges, seizure, dizziness, headache, agitation, confusion, hallucinations, arthralgia, arthritis, joint disorder, interstitial nephritis, renal dysfunction, toxic nephropathy, increased blood urea nitrogen, increased creatinine, hemorrhage,
Other reported side effects include anal pruritis, some bone marrow suppression, rash, Steven's Johnson syndrome, hepatitis, elevated LFT's, genital pruritus, genital candidiasis, vulvovaginitis/vaginitis and vaginal discharges, seizure, dizziness, headache, agitation, confusion, hallucinations, arthralgia, arthritis, joint disorder, interstitial nephritis, renal dysfunction, toxic nephropathy, increased blood urea nitrogen, increased creatinine, hemorrhage,
DOSAGE
ADULT
Max dose: 4 g per day
SKIN/SOFT TISSUE INFECTION - 500mg po q6h x7-14d
CYSTITIS - 250mg po q6h or 500mg po q12h 3-7d
PROSTATITIS - 250mg po q6h or 500mg q12h x7-14d
PYELONEPHRITIS - 250mg po q6h or 500mg q12h x7-14d
PEDIATRICS
SKIN or SOFT TISSUE, CYSTITIS, PROSTATITIS, PYELONEPHRITIS - 12.5mg to 25mg/kg po q12h
CYSTITIS TREATMENT - 15mg/kg/dose q8h x7-14d
UTI PROPHYLAXIS - 10mg/kg daily
RENAL DOSING
CrCl 30-59ml/min - max dose 1g po qd
CrCl 15-29ml/min - max dose 250mg po q8-12h
CrCl 5-14ml/min - max dose 250mg po qd
CrCl 1-4ml/min - max dose 250mg po q48-60h
DIALYSIS
unknown*
Max dose: 4 g per day
SKIN/SOFT TISSUE INFECTION - 500mg po q6h x7-14d
CYSTITIS - 250mg po q6h or 500mg po q12h 3-7d
PROSTATITIS - 250mg po q6h or 500mg q12h x7-14d
PYELONEPHRITIS - 250mg po q6h or 500mg q12h x7-14d
PEDIATRICS
SKIN or SOFT TISSUE, CYSTITIS, PROSTATITIS, PYELONEPHRITIS - 12.5mg to 25mg/kg po q12h
CYSTITIS TREATMENT - 15mg/kg/dose q8h x7-14d
UTI PROPHYLAXIS - 10mg/kg daily
RENAL DOSING
CrCl 30-59ml/min - max dose 1g po qd
CrCl 15-29ml/min - max dose 250mg po q8-12h
CrCl 5-14ml/min - max dose 250mg po qd
CrCl 1-4ml/min - max dose 250mg po q48-60h
DIALYSIS
unknown*
- Tulane University School of Medicine.
- Deck DH, Winston LG (2012): Beta-Lactam & Other Cell Wall- & Membrane-Active Antibiotics (Chapter 43). In: Basic and Clinical Pharmacology. 12e. Katzung BG, Masters SB, Trevor AJ (Editors). McGraw-Hill / Lange.