Metamizol Promedo (Metamizole Sodium Monohydrate)

Metamizole sodium is used for analgesic and antipyretic therapy in conditions where pain or fever require effective control.

• Moderate to severe pain: provides analgesia when other analgesics are inadequate or not tolerated.
• High fever: lowers elevated body temperature in febrile patients.
• Post‑operative pain: helps control discomfort following surgical procedures.

• Metamizole sodium inhibits cyclooxygenase enzymes, reducing prostaglandin synthesis, which diminishes peripheral sensitization to pain. It also modulates central pain pathways by influencing neurotransmitter release, contributing to its antipyretic effect through action on the hypothalamic thermoregulatory center.

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

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Vomiting: occasional episodes after dosing.
• Dizziness: transient light‑headedness.
• Hypotension: occasional drop in blood pressure.
• Skin rash: mild erythema or itching.
• Headache: occasional mild headache.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells.
• Aplastic anemia: bone‑marrow failure leading to pancytopenia.
• Stevens‑Johnson syndrome: severe skin and mucosal reaction.
• Hepatic failure: rare liver injury.
• Severe hypotensive shock: abrupt blood pressure collapse.
• Blood dyscrasias: abnormal blood cell counts.

Before prescribing Metamizole sodium, clinicians should consider several safety measures.

• Renal function assessment: evaluate kidney status, especially in elderly patients.
• Hematologic monitoring: perform regular blood counts to detect agranulocytosis early.
• Hypersensitivity screening: avoid use in patients with known allergy to pyrazolones.
• Caution in the elderly: dose adjustments may be required due to increased sensitivity.
• Concomitant NSAIDs: avoid combining with other non‑steroidal anti‑inflammatory drugs to reduce gastrointestinal risk.
• Store at room temperature: keep in the original pack, protect from moisture.

Metamizole sodium can interact with several drug classes, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Myelosuppressive agents: concurrent use may amplify risk of severe blood dyscrasias.
• Drugs known to cause agranulocytosis (e.g., carbamazepine): increase likelihood of life‑threatening neutropenia.
• Anticoagulants: may enhance bleeding tendency.

Moderate Interactions (Monitor Closely)

• NSAIDs: combined use raises risk of gastrointestinal ulceration.
• ACE inhibitors: potential for reduced renal perfusion.
• Oral hypoglycemics: may alter glucose control, requiring dose adjustment.
• Lithium: possible increase in lithium serum levels.