Cephalosporins

Cephalosporins are a diverse group of β-lactam antibiotics, widely used in both hospital and community settings. Their spectrum broadens with each generation, covering a range of Gram-positive and Gram-negative organisms including Pseudomonas and MRSA (in some cases).

Let’s break this down into a pharmacist-friendly format that covers mechanism, usage, precautions, and practical tips, especially useful for your counselling, dispensing, and clinical decision-making.

General Principles of Link:

Anti-Infectives

Medicine Link

1. Cefaclor – 2nd Gen Oral Cephalosporin

2. Cefalexin (Cephalexin) – 1st Gen Oral Cephalosporin

3. Cefotaxime – 3rd Gen IV/IM Cephalosporin

4. Cefuroxime – 2nd Gen, Oral/IV

   
   

How Do Cephalosporins Work?

Cephalosporins inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan formation. This leads to cell lysis and bacterial death — making them bactericidal.

Class: β-lactam antibiotics Mode: Time-dependent killing

Cephalosporin Generations Overview

Generation	Key Drugs	Coverage Highlights
1st	Cefalexin	Mostly Gram-positive (Staph/Strep)
2nd	Cefaclor, Cefuroxime	Added Gram-negative (H. influenzae)
3rd	Cefotaxime, Ceftriaxone, Ceftazidime	Broader Gram-neg, incl. meningitis & Pseudomonas
4th	Cefepime	Broadest Gram+ and Gram- coverage, incl. Pseudomonas
5th	Ceftaroline	MRSA + broad Gram-positive + moderate Gram-neg

Key Cephalosporins – Clinical Profiles

Summary Table

Drug	Form	Use	Max Adult Dose	Key Notes
Cefaclor	Oral	URTI, OM	1.5 g/day	High serum sickness risk
Cefalexin	Oral	UTI, SSTI	4 g/day	Good staph/strep coverage
Cefotaxime	IV/IM	Meningitis, sepsis	12 g/day	Preferred in neonates
Cefuroxime	Oral/IV	ENT/resp, gonorrhoea	1 g/day (oral)	Take with food

1. Cefaclor – 2nd Gen Oral Cephalosporin

Cefaclor

✅ Use:

• Otitis media, acute sinusitis

• Respiratory infections (H. influenzae)

💊 Dose:

• Adult: 250–500 mg q8h

• CR tabs: 375–750 mg q12h

• Child: 10–15 mg/kg q8h (max 500 mg/dose)

⚠️ Caution:

• Higher risk of serum sickness-like syndrome, esp. in children

• Avoid in severe penicillin allergy

• Safe in pregnancy and breastfeeding

🗣️ Counselling:

• Take with food

• Swallow CR tabs whole

• Report rash, joint pain, or fever

🧠 Practice Tip:

• Prefer cefuroxime in kids (lower serum sickness risk)

2. Cefalexin (Cephalexin) – 1st Gen Oral Cephalosporin

Cefalexin (Cephalexin)

Cephalexin (Keflex)

CEPHALEXIN SYRUPS

✅ Use:

• UTIs, tonsillitis, skin infections

• Staph/strep infections in penicillin-allergic patients

• UTI prophylaxis

💊 Dose:

• Adult: 250–500 mg q6–12h (max 4 g/day)

• Child: 12.5–25 mg/kg q6h (max 1 g/dose)

⚠️ Caution:

• Reduce dose if CrCl <10 mL/min

• Risk of neurotoxicity at high doses

• Safe in pregnancy & breastfeeding

🗣️ Counselling:

• Take with or without food

• Complete course

• Report signs of allergy

🧠 Practice Tip:

• BD dosing OK for mild infections

• Monitor renal function in high-dose or long use

  
  

3. Cefotaxime – 3rd Gen IV/IM Cephalosporin

Cefotax

✅ Use:

• Bacterial meningitis, PID, orbital cellulitis

• Septicaemia, CAP (with azithromycin)

💊 Dose:

• Adult: 1–2 g IV q8–12h (max 12 g/day)

• Severe: 2 g q6h

• Child: 50 mg/kg q6h (max 2 g)

• Neonates: Preferred over ceftriaxone

⚠️ Caution:

• High sodium load (48 mg/g)

• Risk of seizures with rapid IV bolus

• Reduce dose in CrCl <5 mL/min

🗣️ Counselling/Practice:

• IV: Inject over 3–5 min

• Avoid mixing with aminoglycosides

• Monitor FBC and renal if >10 days use

4. Cefuroxime – 2nd Gen, Oral/IV

 Cefuroxime (Zinnat)

✅ Use:

• ENT and respiratory infections

• Gonorrhoea (oral 1 g stat)

• Surgical prophylaxis (IV)

💊 Dose:

• Adult oral: 250–500 mg BD

• IV prophylaxis: 1.5 g pre-op

• Children: 10–15 mg/kg BD (max 500 mg/dose)

⚠️ Caution:

• Reduce dose if CrCl <20 mL/min

• Avoid in cephalosporin allergy

🗣️ Counselling:

• Take with food

• May cause mild GI upset

• Report severe diarrhoea or allergy

🧠 Practice Tip:

• Good H. influenzae coverage

• Prefer over cefaclor in paediatrics

  
  

Precautions & Cross-Reactivity

Risk Factor	Clinical Advice
Penicillin allergy	Avoid cephalosporins in immediate/severe allergy
Renal impairment	Reduce dose, esp. IV forms; monitor for neurotoxicity
Elderly	Watch renal function and GI tolerance
Pregnancy/Breastfeeding	Most cephalosporins are safe

❌ Common Adverse Effects

Frequency	Effects
Common	GI upset, headache, rash
Infrequent	Candida superinfection, C. difficile
Rare	Neurotoxicity, SJS/TEN, serum sickness (esp. cefaclor), bleeding (ceftriaxone)

Practice Points & Community Pharmacy Tips

• Check allergy history before dispensing

• Watch for serum sickness in children (rash + joint pain + fever)

• Refrigerate oral suspensions (e.g., cefaclor)

• Counsel on diarrhoea risk and hydration

• Avoid unnecessary use of 3rd gen agents → VRE risk

• Don’t mix IV cephalosporins with aminoglycosides — risk of inactivation

Resistance & Stewardship Considerations

Resistance Type	Cephalosporin Activity
ESBL	❌ Resistant to all cephalosporins
KPC/NDM-1	❌ Resistant to most β-lactams
ESCAPPM (e.g., Enterobacter)	Avoid cephalosporins – inducible resistance

🧠 Always reassess broad-spectrum cephalosporin use after 48–72 hrs based on cultures.