[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/) › Ceftriaxone [Pharmacology](https://durgical.com/en/pharmacology/) · [Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/) # Ceftriaxone A third-generation cephalosporin given by injection that reaches the brain and lasts all day; a mainstay for gonorrhoea, meningitis and pyelonephritis. Updated 2026-11-01 - Class: [Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/) - Enzyme: Penicillin-binding protein 2 (PBP2) and other PBPs - ATC code: J01DD04 - WHO Model List of Essential Medicines ✂**Penicillin-binding protein 2 (PBP2) and other PBPs**Ceftriaxone ⓘ The figure shows the transpeptidase domain of PBP2 from Neisseria gonorrhoeae acylated by ceftriaxone: the opened drug is bonded to the active-site serine. **Target in 3D:** Penicillin-binding protein 2 (PBP2) and other PBPs. PDB structure 6P54 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6P54) · Drag to rotate · pinch to zoom ## Mechanism of action Ceftriaxone acylates the PBPs and blocks peptidoglycan cross-linking, like the other β-lactams. It keeps activity in the presence of some β-lactamases (penicillinases and cephalosporinases), which gives it strong activity against gram-negatives such as gonococcus, meningococcus, H. influenzae and E. coli, and against pneumococcus and other streptococci. - Resists many β-lactamases and reaches the PBPs intact - Acylates PBP2 and other PBPs - Cell-wall cross-linking stops - The bacterium lyses; one daily dose keeps working ## Pharmacokinetics **Absorption** Not absorbed by mouth; given IV or IM. **Distribution** Wide; penetrates inflamed meninges; largely and reversibly bound to plasma proteins. **Elimination** Two routes: a third to two-thirds unchanged in the urine, the rest in bile; for this reason kidney impairment alone usually needs no change, except when severe. **Half-life** About 6 to 9 hours in healthy adults, long for a β-lactam, which allows once-daily use. ## Indications - Uncomplicated gonorrhoea: the recommended treatment, with surveillance for resistance. [Gonorrhoea →](https://durgical.com/en/conditions/gonorrhoea/) - Bacterial meningitis caused by H. influenzae, meningococcus or pneumococcus. [Bacterial meningitis →](https://durgical.com/en/conditions/bacterial-meningitis/) - Lower respiratory tract infections, including community-acquired pneumonia in hospital. [Community-acquired pneumonia →](https://durgical.com/en/conditions/community-acquired-pneumonia/) - Complicated urinary tract infections such as acute pyelonephritis. [Acute pyelonephritis →](https://durgical.com/en/conditions/acute-pyelonephritis/) - Prevention in close contacts of meningococcal disease and before some surgeries. ## Adverse effects ### Common - Pain at the injection site - Diarrhoea - Rash - Raised liver enzymes and eosinophilia ### Serious (rare, important) - Biliary sludge or pseudolithiasis: a ceftriaxone–calcium salt in the gallbladder, transient and reversible when the drug stops - In newborns: it displaces bilirubin from albumin (bilirubin encephalopathy risk) and can form calcium precipitates in lungs and kidneys - Clostridioides difficile diarrhoea, from mild to fatal colitis - Severe haemolytic anaemia, sometimes fatal (rare) ## Contraindications - Anaphylaxis to ceftriaxone or other β-lactams - Premature newborns and newborns with hyperbilirubinaemia - Newborns (28 days or younger) who need IV calcium-containing solutions ## Key interactions **IV calcium-containing solutions** Ceftriaxone–calcium precipitates; never given at the same time, and avoided altogether in newborns who need calcium. **Vitamin K antagonists (warfarin)** Higher bleeding risk; prothrombin time can change. ## What is monitored - Right-upper-quadrant pain on long courses (biliary sludge) - Blood count and liver tests on long courses - Bilirubin in newborns ## Memory aid Think of ceftriaxone as a day-long night guard with two exits, bile and urine: it watches the brain, the urethra and the kidney, but calcium in a newborn's drip makes it turn to stone. ## Test yourself Think of the answer, then tap the question to see it. ## A child on a long course of ceftriaxone develops right-upper-quadrant pain and ultrasound shows gallbladder sludge. What is the mechanism? Ceftriaxone is partly excreted in bile, where it forms a calcium salt that precipitates (pseudolithiasis). It is transient and reverses after the drug is stopped. ## Why is ceftriaxone avoided in jaundiced newborns? It displaces bilirubin from albumin, raising free bilirubin and the risk of kernicterus. ## Why can ceftriaxone usually be used without adjustment when only the kidneys are impaired? It is cleared by two routes, urine and bile, so biliary excretion compensates; only severe kidney impairment calls for caution. ## Why must ceftriaxone not be given at the same time as IV calcium-containing solutions? The two form ceftriaxone–calcium precipitates; in newborns these have lodged in the lungs and kidneys, so the combination is contraindicated. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/ceftriaxone/) ## Related drugs - [Benzylpenicillin (penicillin G)](https://durgical.com/en/pharmacology/benzylpenicillin/) - [Amoxicillin](https://durgical.com/en/pharmacology/amoxicillin/) ## Related conditions - [Gonorrhoea](https://durgical.com/en/conditions/gonorrhoea/) - [Bacterial meningitis](https://durgical.com/en/conditions/bacterial-meningitis/) - [Community-acquired pneumonia](https://durgical.com/en/conditions/community-acquired-pneumonia/) - [Acute pyelonephritis](https://durgical.com/en/conditions/acute-pyelonephritis/) [← Back to the class: Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Ceftriaxone Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a685032.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - CEFTRIAXONE injection, powder, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8351aa37-552d-471d-b293-c564dcb6ec29) (DailyMed (U.S. National Library of Medicine), 2026); [DailyMed - CEFTRIAXONE- ceftriaxone sodium injection, powder, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5cd2d96f-83e5-4326-ae87-d0ede4ba493a) (DailyMed (U.S. National Library of Medicine), 2026); [Gonococcal Infections Among Adolescents and Adults - STI Treatment Guidelines](https://www.cdc.gov/std/treatment-guidelines/gonorrhea-adults.htm) (Centers for Disease Control and Prevention (CDC), 2021). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/ceftriaxone/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/ceftriaxone/