Metamizol Normon (Metamizole Magnesium)

Metamizol is a non‑opioid analgesic and antipyretic that acts on pain and fever pathways.

• Pain: provides effective relief of moderate to severe acute pain.
• Fever: lowers elevated body temperature when other antipyretics are insufficient.
• Post‑operative pain: helps control pain following surgical procedures.

• Metamizole inhibits cyclooxygenase enzymes and modulates the synthesis of prostaglandins and other inflammatory mediators, leading to reduced nociceptive signaling and fever generation. Its exact mechanism is not fully elucidated, but the combined anti‑inflammatory and analgesic actions contribute to its clinical effects.

Metamizole may cause a range of adverse reactions, from mild to serious.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Vomiting: occasional emesis after dosing.
• Dizziness: transient light‑headedness.
• Hypotension: temporary drop in blood pressure, especially with rapid intravenous administration.
• Skin rash: mild erythematous eruptions.
• Elevated liver enzymes: transient laboratory changes.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells, requiring immediate medical attention.
• Stevens‑Johnson syndrome: rare but life‑threatening skin reaction.
• Anaphylaxis: acute allergic response with airway compromise.
• Hepatic failure: rare severe liver injury.
• Renal impairment: possible decline in kidney function.
• Blood dyscrasias: other serious hematologic abnormalities.

Metamizole should be used with careful clinical oversight.

• Baseline blood count: obtain complete blood count before initiating therapy.
• Monitor for infection: watch for signs of neutropenia such as fever or sore throat.
• Renal or hepatic impairment: adjust use and monitor organ function.
• Known hypersensitivity: avoid in patients with documented allergy to pyrazolones.
• Medical supervision: administer only under prescriber direction.
• Store at ambient temperature: keep in the original packaging, protect from moisture and direct sunlight.

Metamizole can interact with several drug classes, requiring attention to potential risks.

Major Interactions (Avoid)

• Warfarin: increased anticoagulant effect and bleeding risk.
• Other myelosuppressive agents (e.g., chemotherapy): heightened risk of agranulocytosis.
• ACE inhibitors: additive hypotensive effect.
• Lithium: possible increase in lithium serum levels.
• Sulfonamides: potential for cross‑reactivity in hypersensitive individuals.

Moderate Interactions (Monitor Closely)

• NSAIDs: combined gastrointestinal irritation.
• Diuretics: may enhance hypotensive response.
• Alcohol: can exacerbate dizziness and hypotension.
• Antihypertensives: monitor blood pressure for additive lowering.