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

7 major

SEVERE in our sources

PREGNANCY

Use only if clearly needed — limited human data

FDA category + note

Top interactionssee all 11 →

BupropionSevereDatabaseDDInter
DivalproexSevereDatabase
IohexolSevereDatabaseDDInter
IopamidolSevereDatabaseDDInter

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

Divalproex

Severe

Database

Rapid and significant decrease in valproate levels, leading to loss of seizure control.

Avoid co-administration. If ertapenem is essential, consider alternative anticonvulsants or closely monitor valproate levels and increase valproate dose significantly. Monitor for seizure recurrence.

Iohexol

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Iopamidol

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Sodium Valproate

Severe

Database

Rapid and significant decrease in valproate plasma concentrations, leading to loss of seizure control and increased risk of breakthrough seizures.

Avoid concomitant use if possible. If ertapenem is essential, consider alternative antiepileptic drugs. If co-administration is unavoidable, monitor valproate levels closely and consider increasing valproate dose significantly or switching to an alternative antiepileptic drug. Monitor for seizure recurrence.

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

Source: Kimi deep-research + Cla

Amide Local Anaesthetics