Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Meropenem

Meropenem

Carbapenem (IV)

ESBLMDRICUΞ²-lactam

Indication

ESBL bacteremia β€’ HAP/VAP (combo) β€’ intra-abdominal sepsis β€’ meningitis (selected) β€’ febrile neutropenia

At a glance

INDICATIONS (CORE USE)

Broad gram-negative + anaerobe; ESBL definitive therapy often carbapenem; **seizure risk lower than imipenem** β€” still caution + renal adjust + valproate interaction.

ADULT DOSE (STANDARD)

1 g IV q8h standard; extended infusion; meningitis higher per protocol

MAX DOSE

~6 g/day in selected extended-infusion protocols β€” renal cap

Route

IV

PEDIATRIC DOSE

20–40 mg/kg q8h (max per peds meningitis dosing tables)

Do not miss

Must-not-miss safety points

Major warning

- Ξ²-lactam anaphylaxis (cross-reactivity concern with severe penicillin allergy β€” test dose / desensitization pathways institution-specific) - **Valproate: meropenem β†’ rapid VPA loss β†’ seizure breakthrough** β€” avoid combo or substitute AED - Renal adjustment mandatory - Carbapenem-resistant organisms (CRE) β†’ treatment failure β€” infection control + adjuncts

Indications

USE IF: ESBL infection, polymicrobial intra-abd sepsis, severe pseudomonal infection when susceptible, meningitis per guideline. AVOID IF: Patient on valproate without AED switch plan; mild infections treatable narrower; MRSA not covered as monotherapy.

Primary

  • ESBL-producing Enterobacterales invasive infection (often definitive therapy)
  • Severe polymicrobial intra-abdominal infection per guideline
  • Hospital-acquired pneumonia / VAP when broad gram-negative + anaerobe coverage needed and susceptibility supports

Secondary

  • Febrile neutropenia high-risk regimens
  • Meningitis in selected cases per ID

Other

  • CRE treatment only as part of specialist regimen with active in vitro agent β€” not generic monotherapy

Dosing

STANDARD (ADULT PO)

1 g IV q8h (2 g q8h meningitis/severe; extended infusion 3 h per pharmacy)

ADULT DOSE

1 g IV q8h; 2 g IV q8h some meningitis/ICU; extended infusion 3h common for PK/PD

PEDIATRIC DOSE

Per pediatric reference β€” meningitis uses higher mg/kg.

MAX DOSE

Institution protocols up to 6 g/day extended infusion β€” renal gates.

Practical Note

Dose before HD; redose after HD per pharmacy.

Warnings

Clinical warnings

  • **Ξ²-lactam allergy β€” immediate** (anaphylaxis, angioedema, bronchospasm, hypotension) β†’ **avoid** this agent; use non–β-lactam alternative
  • **Ξ²-lactam allergy β€” non-severe** (maculopapular rash without systemic anaphylaxis features) β†’ **caution**; risk/benefit + allergy/ID pathway; graded challenge or test dose **only** per protocol β€” do not dismiss automatically
  • **Neurotoxicity:** encephalopathy, confusion, myoclonus, seizures β€” **higher risk with CKD, elderly, dose accumulation** (notably cefepime, carbapenems, high-dose penicillins)
  • New CNS symptoms + renal impairment on IV Ξ²-lactam β†’ **hold dose**, check levels/exposure, rule out other causes
  • C. diff
  • CNS adverse effects (especially renal impairment)
  • Drug fever

Adverse effects

  • nausea
  • rash
  • thrombocytosis
  • hepatic enzyme elevation

Contraindications

  • Hypersensitivity to meropenem

Drug interactions

  • **Valproate β€” major** (↓ VPA up to 90% in days)
  • Probenecid

Special populations

Pediatrics

20–40 mg/kg q8h (max per peds meningitis dosing tables)

Pregnancy

Use when life-threatening infection

Lactation

generally considered low risk short courses.

Renal impairment

Strong dose reduction / extended interval in CKD; neurotoxicity if not adjusted. **CrCl scaffold (FMBM β€” titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β‰₯50** β†’ standard interval (per Adult dosing card) - **CrCl 10–50** β†’ extend interval and/or reduce dose (often q12–24h or ↓ dose β€” **product-specific**) - **CrCl <10** β†’ maximal interval extension / dose reduction; **HD: redose post-dialysis** per protocol; AKI β†’ re-estimate CrCl; **neuro signs** β†’ hold/adjust

Hepatic impairment

No standard adjustment.

Elderly

Renal dosing; drug interactions.

Administration

IV infusion 15–30 min or extended per protocol.

Monitoring

  • Monitor: - ICU or CKD β†’ **creatinine daily** β†’ mandatory dose reduction; maladjustment β†’ **neurotoxicity** - **Valproate co-therapy** β†’ avoid overlap; if unavoidable β†’ VPA level + neurology (seizure breakthrough) - CRE / MDR context β†’ infection control + stewardship documentation
  • Recheck: - No clinical improvement at 48–72h β†’ reassess diagnosis, resistance, source control, and drug interactions - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)

Overdose / toxicity

Clinical Picture

**Life-threatening (first):** **CNS toxicity** β€” seizures, encephalopathy, agitation, myoclonus, coma (**↑ CKD, elderly, accumulation**; cefepime, carbapenems, high-dose penicillins). **Allergic:** anaphylaxis / angioedema (separate pathway). **Secondary:** nausea/vomiting/diarrhea mainly with acute massive **oral** co-ingestion or local infusion reaction.

Immediate Actions

Stop Ξ²-lactam β†’ ABCs β†’ **seizure precautions**; benzos if seizures; check renal function / dose vs CrCl; anaphylaxis β†’ epinephrine + ACLS

Antidote

No specific antidote; treat complications (e.g. anaphylaxis β†’ epinephrine per ACLS)

Decontamination

Stop infusion; recent large PO load β†’ charcoal if protected airway + early presentation

Escalation

Status epilepticus, coma, refractory seizures β†’ **ICU**; **severe CNS toxicity or AKI with accumulation β†’ consider hemodialysis** for dialyzable agents β€” nephrology + pharmacy; persistent anaphylaxis β†’ ICU

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

Broad-spectrum rescue drug for **ESBL** + severe polymicrobial sepsis. **Valproate interaction is catastrophic** β€” check med list. Renal dose.

Clinical pearls

Stewardship: narrow ASAP. De-escalation targets: oral fluoroquinolone / TMP-SMX / ceph PO when cultures guide. Infection control for carbapenem-resistant strains. *Stewardship (all antimicrobials):* Empiric choice β†’ syndrome severity + **local antibiogram**; shortest effective course.

Stewardship & safety

  • Valproate
  • Renal adjust
  • AMS narrow

Pharmacokinetics

Renal elimination; penetrates CSF when inflamed at meningitis doses.

Mechanism of action

Carbapenem β€” ultra-broad PBP binding including many Ξ²-lactamase producers.

Common brand names

Saudi Arabia

Meronem, Meropen, Merrem

Global

(placeholder β€” verify local formulary)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Empiric choice β†’ tie to syndrome, severity, and local antibiogram β€” not habit.
  • IV β†’ PO step-down when oral bioavailability and susceptibility allow.
  • Do not use antibiotics for uncomplicated viral illness β€” stewardship.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling

Do not miss

  • Uncomplicated viral URI/bronchitis β†’ antibiotics rarely indicated
  • Narrow or stop when susceptibilities + clinical stability allow
  • VPA seizure loss.
  • CRE mismatch.
  • C. diff after broad therapy.
  • Valproate
  • Renal adjust
  • AMS narrow