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Carbapenem + β-lactamase inhibitor Pregnancy: There are no adequate and well-controlled studies in pregnant women. Animal studies with imipenem/cilastatin have shown reproductive toxicity in monkeys; the potential risk for humans is unknown. Animal studies with relebactam do not indicate direct or indirect harmful effects with respect to reproductive toxicity. Recarbrio should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus. Imipenem and cilastatin are excreted into breast milk in small quantities and it is unknown whether relebactam is excreted in human milk; a risk to breastfed newborns/infants cannot be excluded, so a decision must be made whether to discontinue breastfeeding or the medicine. No human fertility data are available.

Imipenem with cilastatin and relebactam

Brand names: Recarbrio

Imipenem with cilastatin and relebactam is an intravenous carbapenem combined with a beta-lactamase inhibitor, reserved for serious Gram-negative infections, including those with limited treatment options such as certain carbapenem-resistant organisms.

Adult dose

Dose: Hospital-acquired pneumonia, including ventilator-associated pneumonia (and bacteraemia in association with, or suspected to be associated with, HAP or VAP), and infections due to aerobic Gram-negative organisms in patients with limited treatment options: 500 mg/500 mg/250 mg (imipenem/cilastatin/relebactam) in adults with a creatinine clearance of 90 mL/min or more
Route: Intravenous infusion over 30 minutes
Frequency: Every 6 hours. Duration of treatment 7 to 14 days for HAP/VAP; for infections due to aerobic Gram-negative organisms in patients with limited treatment options, duration in accordance with the site of infection (for complicated intra-abdominal infection and complicated urinary tract infection the recommended treatment duration is 5 to 10 days, and treatment may continue up to 14 days)
Max: 500 mg/500 mg/250 mg every 6 hours is the highest recommended dose and applies only to adults with a creatinine clearance of 90 mL/min or more. Doses are REDUCED in renal impairment: 400/400/200 mg for CrCl less than 90 down to 60 or more; 300/300/150 mg for less than 60 down to 30 or more; 200/200/100 mg for less than 30 down to 15 or more; and 200/200/100 mg in end stage renal disease on haemodialysis, timed to follow haemodialysis.
Indication scope (SPC section 4.2): it is recommended that Recarbrio should be used to treat infections due to aerobic Gram-negative organisms in patients with limited treatment options only after consultation with a physician with appropriate experience in the management of infectious diseases. Renal function is calculated using the Cockcroft-Gault formula in adults. For HAP or VAP patients with a CrCl greater than 250 mL/min, and for patients with complicated intra-abdominal infection or complicated urinary tract infection (including pyelonephritis) with a CrCl greater than 150 mL/min, the recommended dose may not be sufficient. Adults with a CrCl less than 15 mL/min should not receive imipenem/cilastatin/relebactam unless haemodialysis is instituted within 48 hours; there is inadequate information to recommend use in patients undergoing peritoneal dialysis. No dose adjustment is required in hepatic impairment or in the elderly. Recarbrio is supplied as a single vial in a fixed-dose combination, so the dose of each component is adjusted equally during preparation. Concomitant use with valproic acid or divalproex sodium is not recommended (increased seizure potential).

Paediatric dose

Dose: 37.5 mg/kg
Route: Intravenous infusion over 60 minutes in patients weighing 2 kg to less than 30 kg (over 30 minutes in those weighing 30 kg or more, who receive the fixed adult dose)
Frequency: WEIGHT BAND - this per-kilogram dose applies ONLY to patients weighing 2 kg to less than 30 kg; at 30 kg and above the fixed adult dose is used instead and the per-kilogram calculation must not be applied. Within that band: every 6 hours from 3 months to less than 18 years; every 8 hours from birth to less than 3 months
Max: 500 mg/500 mg/250 mg every 6 hours over 30 minutes is the ceiling - it is the fixed adult dose, given unchanged to paediatric patients weighing 30 kg or more and aged under 18 years, who do not receive a per-kilogram dose. Those weighing 30 kg or more with an eGFR less than 90 mL/min/1.73 m2 need the same reductions as adults (400/400/200, 300/300/150 or 200/200/100 mg).
SPC section 4.2, Table 2. The 37.5 mg/kg figure is the label's own combined per-DOSE figure and comprises imipenem 15 mg/kg, cilastatin 15 mg/kg and relebactam 7.5 mg/kg. It applies to patients weighing 2 kg to less than 30 kg. Paediatric renal function is estimated by the bedside Schwartz formula. Imipenem/cilastatin/relebactam is NOT recommended in paediatric patients weighing less than 30 kg with renal impairment. Safety and efficacy have not been established in children weighing less than 30 kg with renal impairment, children weighing less than 2 kg, or preterm infants (less than 37 weeks post-menstrual age) - no data are available. Treatment duration for paediatric HAP/VAP is the same as for adults; for infections due to aerobic Gram-negative organisms with limited treatment options, duration is based on prescriber discretion. Special awareness of neurological symptoms or convulsions is needed in children with known risk factors for seizures or on concomitant medicines that lower the seizure threshold. Verify against a children's formulary before prescribing.

Dose adjustments

Renal

Adults with a CrCl less than 90 mL/min require dose reduction (SPC section 4.2, Table 3): CrCl less than 90 down to 60 or more - 400/400/200 mg; less than 60 down to 30 or more - 300/300/150 mg; less than 30 down to 15 or more - 200/200/100 mg; end stage renal disease on haemodialysis - 200/200/100 mg administered after haemodialysis. Infusion time and frequency are unchanged. Adults with a CrCl less than 15 mL/min should not receive the drug unless haemodialysis is instituted within 48 hours. Paediatric patients weighing at least 30 kg with an eGFR less than 90 mL/min/1.73 m2 follow the same table; it is not recommended in paediatric patients weighing less than 30 kg with renal impairment. Imipenem, cilastatin and relebactam are cleared during haemodialysis.

Hepatic

No dose adjustment is required in patients with impaired hepatic function, but hepatic function should be closely monitored during treatment.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

SPC section 4.2, Table 2. The 37.5 mg/kg figure is the label's own combined per-DOSE figure and comprises imipenem 15 mg/kg, cilastatin 15 mg/kg and relebactam 7.5 mg/kg. It applies to patients weighing 2 kg to less than 30 kg. Paediatric renal function is estimated by the bedside Schwartz formula. Imipenem/cilastatin/relebactam is NOT recommended in paediatric patients weighing less than 30 kg with renal impairment. Safety and efficacy have not been established in children weighing less than 30 kg with renal impairment, children weighing less than 2 kg, or preterm infants (less than 37 weeks post-menstrual age) - no data are available. Treatment duration for paediatric HAP/VAP is the same as for adults; for infections due to aerobic Gram-negative organisms with limited treatment options, duration is based on prescriber discretion. Special awareness of neurological symptoms or convulsions is needed in children with known risk factors for seizures or on concomitant medicines that lower the seizure threshold. Verify against a children's formulary before prescribing.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substances or to any of the excipients
  • Hypersensitivity to any other carbapenem antibacterial agent
  • Severe hypersensitivity (e.g. anaphylactic reaction, severe skin reaction) to any other type of beta-lactam antibacterial agent (e.g. penicillins, cephalosporins or monobactams)

Side effects

  • Diarrhoea - the most frequently occurring adverse reaction (2% or more) in adults; also alanine aminotransferase increased and aspartate aminotransferase increased in the Phase 3 HAP/VAP study
  • Nausea and vomiting
  • Serious and occasionally fatal hypersensitivity (anaphylactic) reactions
  • Seizures, confusional states, myoclonic activity, hallucinations, dizziness, somnolence, encephalopathy, headache
  • Clostridioides difficile-associated diarrhoea, pseudomembranous colitis and haemorrhagic colitis
  • Hepatic failure, hepatitis, fulminant hepatitis and jaundice
  • Severe skin reactions - toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, exfoliative dermatitis, angioedema
  • Blood disorders - eosinophilia, pancytopenia, neutropenia, leukopenia, thrombocytopenia, agranulocytosis, haemolytic anaemia, bone marrow depression
  • Elevations in serum creatinine
  • This side-effect list may be incomplete — check the full SPC.

Interactions

  • Valproic acid / divalproex sodium - concomitant use is not recommended because of increased seizure potential. Antibacterials other than carbapenems should be considered in patients whose seizures are well controlled on valproate; if this medicine is necessary, supplemental anticonvulsant therapy should be considered (SPC section 4.4)

Monitoring

  • Hepatic function should be closely monitored during treatment because of the risk of hepatic toxicity (raised transaminases, hepatic failure, fulminant hepatitis); patients with pre-existing liver disorders should have liver function monitored, though no dose adjustment is needed
  • Monitor creatinine clearance in patients with fluctuating renal function, since the dose is renally adjusted
  • Before initiating therapy, make careful inquiry about previous hypersensitivity reactions to carbapenems, penicillins, cephalosporins, other beta-lactams and other allergens; discontinue immediately if an allergic reaction occurs
  • Watch for CNS reactions (seizures, confusional states, myoclonic activity), particularly in patients with CNS disorders such as brain lesions or a history of seizures, and in those with compromised renal function
  • Consider Clostridioides difficile-associated diarrhoea in any patient who develops diarrhoea during or after treatment

Clinical monograph

How it works

Imipenem inhibits bacterial cell wall synthesis by binding penicillin-binding proteins, cilastatin blocks renal dehydropeptidase to protect imipenem from degradation, and relebactam inhibits key beta-lactamases to restore activity against resistant organisms.

Prescribing in practice

  • Reserve this agent for confirmed or strongly suspected multidrug-resistant Gram-negative infection under specialist and microbiology guidance to preserve its activity.
  • Imipenem lowers the seizure threshold, so use cautiously in patients with CNS disorders or renal impairment, and it markedly reduces valproate levels with risk of loss of seizure control.
  • The dose requires adjustment in renal impairment, and there is potential for cross-reactivity in patients with severe penicillin allergy.

Monitoring

Monitor renal function to guide dosing and observe for neurological effects such as seizures, particularly in at-risk patients.

Counselling the patient

  • This is a reserve antibiotic given in hospital for difficult-to-treat infections.
  • Tell the team about any previous reactions to penicillins or carbapenems.
  • Report any twitching, confusion or seizures promptly.

Evidence & guidelines

Imipenem-cilastatin-relebactam is positioned as a reserve antibiotic for resistant Gram-negative infections within antimicrobial stewardship frameworks.

Reference: SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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