Cefalosporins have a broader activity than penicillins, esp 3rd generation eg cefotaxime, ceftriaxone which are effective against most gram positives and gram negatives.

Good for meningitis (penetrate inflamed meninges at high dose) but not effective against pseudomonas, enterococcus, listeria, MRSA, and not that great against normal staphs so beware if possible line infection or neonatal meningitis. Some pneumococci can be resistant (1st line meningitis treatment in US is cef with vanc).

Ceftriaxone is drug of choice for Lyme with complications; it is not recommended for immediate treatment of meningococcal disease as any subsequent calcium containing infusions will reduce its plasma levels.

Ceftriaxone also eradicates meningococcal colonization – since cefotaxime is essentially equivalent, no reason to switch just for this indication.

Contraindications to ceftriaxone:

• Concomitant treatment with intravenous calcium (including total parenteral nutrition) in premature and full-term neonates—risk of precipitation in urine and lungs (fatal reactions) ;
• full-term neonates with jaundice, hypoalbuminaemia, acidosis, unconjugated hyperbilirubinaemia, or impaired bilirubin binding—risk of developing bilirubin encephalopathy;
• premature neonates less than 41 weeks corrected gestational age