Clinical beta
FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.
Drug Monograph
Cephalexin
First-generation oral cephalosporin
Indication
Uncomplicated SSTI • UTI • otitis media (susceptible organisms) • streptococcal pharyngitis (selected cases)
INDICATIONS (CORE USE)
Susceptible MSSA / strep SSTI; uncomplicated UTI; some streptococcal pharyngitis alternatives — NOT MRSA reliable.
ADULT DOSE (STANDARD)
250–500 mg PO q6–12h (infection-dependent); UTI often 500 mg PO q12h
MAX DOSE
~4 g/day PO (adult) — follow local guideline
Route
PO
PEDIATRIC DOSE
25–50 mg/kg/day PO divided q6–12h (~max 2–4 g/day by indication/weight)
Must-not-miss safety points
Major warning
- **Misuse boundary:** NOT appropriate as sole therapy for **pyelonephritis**, **bacteremia**, or **unstable systemic infection** — escalate route/spectrum when indicated - **MRSA:** **no reliable MRSA coverage** — do not use as monotherapy when MRSA in differential - β-lactam → anaphylaxis risk; severe penicillin allergy → caution / alternative per protocol - Poor MRSA / enterococcus / anaerobe / many gram-neg coverage → treatment failure if wrong bug - Do not use for viral infections — drives resistance + C. diff risk - Renal impairment → reduce dose / extend interval
USE IF: Mild–moderate susceptible MSSA/strep SSTI; uncomplicated UTI; some respiratory/otitis when spectrum fits local susceptibility. AVOID IF: MRSA suspected; serious pseudomonal / ESBL / high-risk gram-negative infection; severe β-lactam allergy when cephalosporin contraindicated.
Primary
Secondary
Other
STANDARD (ADULT PO)
500 mg PO q12h (many mild–moderate infections)
ADULT DOSE
Uncomplicated UTI: often 500 mg PO q12h × ~7–14d (female cystitis often shorter course per guideline) SSTI mild–moderate: 500 mg PO q6–12h Pharyngitis alternative: per local guideline dosing
PEDIATRIC DOSE
25–50 mg/kg/day PO divided q6–12h (use suspension if needed).
MAX DOSE
Adult ~4 g/day PO ceiling in many references — reduce in CKD.
Practical Note
Take with food if GI upset. Verify culture/susceptibility for recurrent UTI.
Clinical warnings
Adverse effects
Pediatrics
25–50 mg/kg/day PO divided q6–12h (~max 2–4 g/day by indication/weight)
Pregnancy
Pregnancy: generally considered low risk (cephalosporin class) — use when clearly indicated.
Lactation
compatible with breastfeeding for most infants.
Renal impairment
CrCl <30–50 mL/min → extend interval and/or reduce total daily dose (pharmacy adjust). Dialysis: give after HD / per protocol. **CrCl scaffold (FMBM — titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl ≥50** → usual PO regimen - **CrCl 10–50** → extend interval or ↓ total daily dose per label - **CrCl <10** → further reduction; align **HD** timing with absorption / redose per protocol
Hepatic impairment
No routine adjustment; monitor if combined hepato-renal illness.
Elderly
Higher bleeding risk if on anticoagulants; renal dosing; fall risk if delirium from intercurrent illness.
PO with or without food. Complete course for strep pharyngitis. Hydration for UTI.
Clinical Picture
**Life-threatening (first):** **anaphylaxis**; **CNS toxicity** (seizures, encephalopathy) — uncommon vs IV but consider **massive ingestion + severe CKD** or continued dosing in renal failure. **Secondary:** GI upset (nausea, vomiting, diarrhea).
Immediate Actions
Stop drug → ABCs; seizures → benzos; anaphylaxis → epinephrine + ACLS
Antidote
No specific antidote; treat complications (e.g. anaphylaxis → epinephrine per ACLS)
Decontamination
Large recent ingestion → charcoal if appropriate window, airway protected
Escalation
Refractory shock, angioedema, seizures, intractable vomiting → **ED/ICU**; **severe neurotoxicity or renal failure with suspected accumulation → consider hemodialysis** (agent-dependent) — nephrology + pharmacy
Common mistakes, resistance logic, and bedside traps
Oral first-gen ceph for **susceptible** strep/MSSA + many uncomplicated UTIs. → Not your MRSA drug. → Renal adjust.
Stewardship: no antibiotics for viral URI. De-escalation: PO step-down when stable + susceptible. Resistance: rising ESBL in some regions — know your UTI antibiogram. *Stewardship (all antimicrobials):* Empiric choice → syndrome severity + **local antibiogram**; shortest effective course.
PO well absorbed; renal elimination; T½ ~0.5–1 h (adults); penetrates many tissues modestly; CSF not reliable for meningitis.
Binds PBPs → inhibition of cell wall synthesis (bactericidal).
Saudi Arabia
Keflex, Ceporex
Global
(placeholder — verify local formulary)
Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.
Saudi Arabia
International