Carbapenem antibiotic
Imipenem with cilastatin
Brand names: Primaxin
Adult dose
Dose: 500mg–1g IV every 6–8h (max 4g/day)
Route: IV
Frequency: q6-8h
Dose adjustments
Renal
Mandatory — refer to BNF
Clinical pearls
- Severe gram-negative infections incl. ESBL; meropenem usually preferred (lower seizure risk)
- Cilastatin protects against renal dehydropeptidase
Contraindications
- Hypersensitivity to carbapenems
- Severe penicillin allergy (cross-reactivity)
Side effects
- Seizures (highest seizure risk among carbapenems)
- Nausea
- Diarrhoea
- C. difficile
- Eosinophilia
- Hypersensitivity
Interactions
- Valproate (avoid — markedly reduced valproate levels)
- Probenecid
- Ganciclovir (seizures)
Monitoring
- U&E
- FBC
- Neurological exam
Reference: BNF; UK AMR guidance; https://bnf.nice.org.uk/drugs/imipenem-with-cilastatin/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
- Centor / McIsaac Score for Strep Pharyngitis · Throat
- FeverPAIN Score for Strep Throat · Throat
- Jarisch-Herxheimer Reaction Severity Assessment · Treatment Reactions
- PID Severity (CDC Diagnostic Criteria) · Gynaecological Infections
- FAST Exam Protocol — Focused Assessment with Sonography in Trauma · Trauma
- Gustilo-Anderson Classification (Open Fractures) · Fracture Classification
Drugs
Pathways
- Infective Endocarditis · ESC 2023 Infective Endocarditis Guidelines; NICE NG41
- Eczema Herpeticum · BAD; NICE CKS
- Suspected Bacterial Meningitis (Adult) · NICE NG240 (2024); NICE NG143 (paeds)
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021
- Returning Traveller — Fever · NaTHNaC; PHE; ESCMID 2018
- Malaria — Diagnosis & Management · PHE 2016; WHO 2023