A combination antibiotic for resistant Gram-negative infections
Ceftolozane with tazobactam
A hospital drip antibiotic combining a cephalosporin with a beta-lactamase blocker, used for serious resistant Gram-negative infections.
What is Ceftolozane with tazobactam?
Ceftolozane with tazobactam is a hospital antibiotic given as a drip into a vein to treat serious infections caused by certain resistant Gram-negative bacteria, such as some complicated urinary and abdominal infections and some chest infections. The ceftolozane part kills the bacteria, while the tazobactam part protects it from enzymes the bacteria use to break antibiotics down. It is a reserve antibiotic kept for difficult infections, so it is used carefully under specialist guidance. People with a penicillin or cephalosporin allergy need to tell their team, and any antibiotic can occasionally lead to a gut infection called Clostridioides difficile.
Education and reference only. This is a plain-language guide to Ceftolozane with tazobactam — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Ceftolozane with tazobactam is a combination antibiotic used in hospital to treat serious bacterial infections, especially those caused by resistant Gram-negative bacteria that other antibiotics may no longer overcome. Ceftolozane is a cephalosporin, part of the wider penicillin-related family, and tazobactam is a beta-lactamase inhibitor that protects it from being destroyed. Together they are used for infections such as some complicated urinary and abdominal infections and certain chest infections. It is given as a drip into a vein and is regarded as a reserve antibiotic, used under specialist guidance to keep it effective for the future.
How it works
Ceftolozane works by stopping bacteria from building their cell walls, which they need to survive, so the bacteria break down and die. Many resistant Gram-negative bacteria make enzymes called beta-lactamases that destroy antibiotics like ceftolozane before they can act. Tazobactam blocks some of these enzymes, so ceftolozane is protected and can work. Combining the two lets the medicine treat infections that ceftolozane alone might not, which is why it is reserved for harder, resistant infections rather than everyday ones. It is given by drip so it reaches the bloodstream reliably.
Company & origin
Originated / developed by: Specialist manufacturer.
A hospital antibiotic used in the UK, given into a vein to treat serious infections caused by resistant Gram-negative bacteria.
Practical use
How to take Ceftolozane with tazobactam
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given as a drip into a vein by hospital staff; you do not take it yourself.
- Tell the team about any allergy to penicillins or cephalosporins before treatment starts.
- Report any new or worsening diarrhoea during or after treatment, as it can signal a gut infection.
- Complete the full course as advised, even if you feel better, to clear the infection properly.
- Mention any kidney problems, as the dose may need adjusting.
Weighing it up
Advantages & disadvantages of Ceftolozane with tazobactam
Advantages
- Can treat serious Gram-negative infections that many other antibiotics no longer work against.
- The tazobactam part protects the antibiotic from enzymes that would otherwise destroy it.
- A valuable reserve option for difficult, resistant hospital infections.
Disadvantages
- Only given as a drip in hospital, not as a tablet at home.
- Can cause a serious allergic reaction in people allergic to penicillins or cephalosporins.
- Like all antibiotics, it can lead to a Clostridioides difficile gut infection.
Practical use
Good to know
The most important thing to understand is that this is a reserve antibiotic, used for serious or resistant infections under specialist guidance, partly to slow the spread of further resistance. Because ceftolozane is related to penicillin, anyone who has had a reaction to penicillins or cephalosporins must tell the team, as there can be cross-reactivity and, rarely, a serious allergic reaction. Like all antibiotics, it can upset the balance of bacteria in the gut and occasionally lead to a troublesome gut infection called Clostridioides difficile, which causes diarrhoea and needs medical attention. It is given as a drip in hospital, with the dose and length of treatment guided by the infection, kidney function and how the person responds.
Who should not take it / use with caution
- People who have had a serious allergic reaction to ceftolozane, tazobactam, or other cephalosporins should not be given it.
- It is used with great care in people with a known penicillin allergy, because of possible cross-reactivity.
- The dose is adjusted, or it is used cautiously, in people with reduced kidney function.
Monitoring
- Checking how the infection responds, often with repeat tests.
- Watching kidney function and adjusting the dose if needed.
- Watching for allergic reactions and for signs of a gut infection such as diarrhoea.
Side effects
- Nausea, diarrhoea or stomach upset.
- Reactions where the drip goes in, headache or trouble sleeping.
- Allergic reactions, which can rarely be serious, and a gut infection called Clostridioides difficile.
Key interactions
- Tell the team about all your medicines, as some may need monitoring alongside it.
- It can affect certain blood and urine tests, so labs should know you are receiving it.
- Other medicines that affect the kidneys may need review when used together.
Available as: A powder made up into a solution and given as a drip into a vein.
Answers
Ceftolozane with tazobactam: frequently asked questions
What is ceftolozane with tazobactam used for?
It is a hospital antibiotic used to treat serious infections caused by resistant Gram-negative bacteria, such as some complicated urinary, abdominal and chest infections.
What does the tazobactam part do?
Tazobactam blocks enzymes that resistant bacteria use to destroy antibiotics, protecting the ceftolozane so it can kill the bacteria.
Can I take it if I am allergic to penicillin?
Tell your team about any penicillin or cephalosporin allergy first, as this antibiotic is related to penicillin and there can be cross-reactivity.
Why is it called a reserve antibiotic?
It is kept for serious or resistant infections and used carefully under specialist guidance, to help keep it effective and slow the spread of resistance.
Can it cause diarrhoea?
Yes, like all antibiotics it can, and new or severe diarrhoea may signal a gut infection called Clostridioides difficile, which needs medical attention.
The wider class
About Cephalosporin with beta-lactamase inhibitor (reserve antibiotic)
Ceftolozane with tazobactam belongs to the cephalosporin with beta-lactamase inhibitor (reserve antibiotic) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.