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

Metformin

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USE IF: Type 2 diabetes mellitus (first-line), insulin resistance states

AVOID IF: Severe renal impairment, acute illness with hypoxia, hemodynamic instability, or lactic acidosis risk

Metformin

Biguanide antihyperglycemic (insulin sensitizer)

AdultPediatricDiabetesRenal safetyHigh-yieldOutpatient

Indication

Type 2 diabetes mellitus • Insulin resistance states

At a glance

INDICATIONS (CORE USE)

- Type 2 diabetes mellitus (first-line)

ADULT DOSE (STANDARD)

Start low (e.g., 500 mg once or twice daily) Titrate gradually based on tolerance and glycemic response

MAX DOSE

Typically up to about 2000-2550 mg/day (formulation dependent)

Route

PO

PEDIATRIC DOSE

Protocol-based

Do not miss

Must-not-miss safety points

Major warning

- Lactic acidosis is rare but serious - Renal function determines safety and dosing - HOLD during acute illness, hypoxia, hemodynamic instability, or contrast exposure - GI intolerance is common and can reduce adherence

Indications

INDICATION: Type 2 diabetes mellitus • Insulin resistance states

Primary

  • Type 2 diabetes mellitus

Secondary

  • Selected insulin resistance states

Dosing

STANDARD (ADULT PO)

Start low and titrate slowly; take with food to reduce GI intolerance

ADULT DOSE

STANDARD (ADULT): - Start low and titrate slowly - Take with food to reduce GI side effects

PEDIATRIC DOSE

Protocol-based

MAX DOSE

Typically up to about 2000-2550 mg/day depending on formulation and tolerance

Practical Note

- Do not escalate rapidly - Extended-release formulations may improve tolerance - Renal function must guide dosing and continuation

Warnings

Clinical warnings

  • Lactic acidosis risk (higher with renal failure, hypoxia, or sepsis)
  • GI intolerance is common (nausea, diarrhea, abdominal discomfort)
  • Long-term use can be associated with vitamin B12 deficiency

Adverse effects

  • Diarrhea
  • Nausea
  • Abdominal discomfort

Contraindications

  • Severe renal impairment (eGFR below guideline-safe threshold)
  • Acute metabolic acidosis
  • Known hypersensitivity

Drug interactions

  • Iodinated contrast media can precipitate acute renal dysfunction; hold metformin around contrast exposure
  • Concomitant drugs that worsen renal function increase accumulation and lactic acidosis risk

Special populations

Pediatrics

Protocol-based

Pregnancy

Pediatrics: Protocol-based Pregnancy/

Lactation

Use per local diabetes protocol and specialist guidance.

Renal impairment

Dose adjustment required by renal function. Avoid in severe renal impairment and reassess promptly with renal deterioration.

Hepatic impairment

Use caution in conditions predisposing to hypoxia or poor perfusion where lactic acidosis risk may rise.

Elderly

Monitor renal function closely and titrate conservatively.

Administration

- Oral dosing - Take with meals - Titrate gradually

Monitoring

  • Monitor: - HbA1c and glucose control - Renal function - GI tolerance and adherence
  • Recheck: - After dose changes - Periodic renal function during maintenance
  • Hold / reassess: - Acute illness (e.g., sepsis, hypoxia, hemodynamic instability) - Contrast exposure - Renal deterioration

Overdose / toxicity

Clinical Picture

Lactic acidosis and GI symptoms

Immediate Actions

Supportive care, correct underlying causes, and urgent escalation when lactic acidosis is suspected

Antidote

No specific antidote

Decontamination

Supportive toxicology-directed management

Escalation

Consider dialysis in severe toxicity or refractory lactic acidosis

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield

  • First-line therapy for type 2 diabetes mellitus
  • Low intrinsic hypoglycemia risk as monotherapy

Clinical

  • Hold during acute illness or contrast exposure
  • Use slower titration or XR formulation to improve tolerance

Safety

  • Most dangerous error is continuing therapy during renal failure, hypoxia, or hemodynamic instability

Pharmacy Tool

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Metformin 100 mg/mL oral solution

solution · oral

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Pharmacokinetics

- Renal elimination - No hepatic metabolism

Mechanism of action

- Reduces hepatic glucose production - Improves insulin sensitivity

Common brand names

Saudi Arabia

Glucophage, Cidophage, Dialon

Global

Fortamet, Metformin, Metformin XR, (placeholder — verify local formulation)

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

Country practice notes

Global data (no country-specific data available)

  • Follow local antimicrobial stewardship policy, hospital formulary, and national resistance guidance.
  • Confirm dosing, stock, and restrictions with institutional pharmacy and current product labeling.

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)
  • Product labeling (metformin)
  • Local diabetes and contrast-management protocols