Drug reference

Ertapenem

Carbapenem beta-lactam antibiotic (group 1) · Antibiotic

Also known as Ertapenem sodium, Invanz

START

1 g IV once daily (IM with lidocaine diluent if IV not feasible)

TYPICAL MAX

1 g/day (500 mg/day if CrCl ≤30)

STOP IF

Anaphylaxis, seizures, severe CDI/skin reaction

WATCH

Renal function (dose-adjust), seizure risk factors, hypersensitivity/diarrhoea; not for Pseudomonas

CDSCO approvedSchedule HATC J01DH03

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 30min · IV onset
PEAK: 30min · end of infusion
t½: 4h · plasma t½
DURATION: 1d · once-daily

EXCRETION

~80% renal (≈38% unchanged) + metabolite

route + CYP

INTERACTIONS

5 major

SEVERE in our sources

PREGNANCY

Use only if clearly needed — limited human data

FDA category + note

Top interactionssee all 9 →

BupropionSevereDatabaseDDInter
IohexolSevereDatabaseDDInter
IopamidolSevereDatabaseDDInter
TramadolSevereDatabaseDDInter

Mechanism

Binds penicillin-binding proteins (esp. PBP2/PBP3) inhibiting cell-wall synthesis → bactericidal; broad Gram-positive/Gram-negative/anaerobe cover but NOT active against Pseudomonas aeruginosa or Acinetobacter; long half-life allows once-daily dosing.

Indications

Complicated intra-abdominal, skin/soft-tissue, urinary, and pelvic infectionsCommunity-acquired pneumoniaSurgical prophylaxis (colorectal)ESBL-producing Enterobacterales infections (non-pseudomonal)

Dosing

Adult: 1 g IV (or IM) once daily.
Pediatric: 3 months–12 years: 15 mg/kg IV BID (max 1 g/day); ≥13 years 1 g once daily.
Renal adjustment: CrCl ≤30 mL/min: 500 mg once daily. Haemodialysis: 500 mg/day; if dose within 6 h before HD give 150 mg supplement after.
Hepatic adjustment: No adjustment.
Geriatric: Adjust per renal function.
Max dose: 1 g/day

Pharmacokinetics

Onset

IV immediate

Peak effect

End of 30-min infusion

Duration

Once-daily (long t½)

Half-life

~4 h

Bioavailability

IV 100%; IM ~90%

Protein binding

~85–95% (concentration-dependent)

Metabolism

Hydrolysis (dehydropeptidase-I) to inactive ring-opened metabolite

Excretion

Renal (~80%, ~38% unchanged + metabolite)

Contraindications

Anaphylaxis to ertapenem/carbapenems or beta-lactams
Hypersensitivity to amide local anaesthetics (IM diluent is lidocaine — for IM route)

Side effects

Common

Diarrhoea/nauseaHeadacheInfusion-site reactions/phlebitisRaised hepatic enzymes

Serious

Anaphylaxis/severe hypersensitivity (carbapenem cross-reactivity)
Seizures (esp. CNS disease, renal impairment, elderly)
Clostridioides difficile colitis
Severe skin reactions (DRESS/SJS rare)

Pregnancy & lactation

Pregnancy

Use only if clearly needed — limited human data

Lactation

Excreted in milk in small amounts; monitor infant — caution

Drug interactions

Bupropion

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Iohexol

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Iopamidol

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Tramadol

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Valproic Acid

Severe

Database

Carbapenems markedly reduce valproate levels → breakthrough seizures

Avoid combination; alternative anticonvulsant + monitor levels