Metamizol Medreg (Metamizole Sodium Monohydrate)

Metamizole is used to manage pain and fever through its action on prostaglandin synthesis and opioid pathways.

• Pain: Reduces moderate to severe acute pain, including postoperative discomfort.
• Fever: Lowers elevated body temperature in febrile conditions.
• Postoperative pain: Provides analgesia after surgical procedures.

• Metamizole inhibits cyclooxygenase enzymes, reducing prostaglandin synthesis, and simultaneously modulates endogenous opioid pathways. This dual action diminishes nociceptive signaling and lowers the hypothalamic set‑point for temperature regulation, resulting in analgesic and antipyretic effects without significant anti‑inflammatory activity.

Metamizole may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Vomiting: occasional episodes after dosing.
• Dizziness: transient light‑headedness.
• Rash: mild skin erythema or pruritus.
• Elevated liver enzymes: mild, reversible changes.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells, potentially life‑threatening.
• Anaphylactic reaction: rapid onset of airway swelling and hypotension.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.

Before prescribing Metamizole, clinicians should consider patient‑specific factors and monitor for adverse events.

• Renal function: assess and monitor in patients with kidney impairment.
• Hepatic function: evaluate liver enzymes prior to initiation.
• Hematologic status: perform baseline complete blood count and monitor for neutropenia.
• Concomitant medications: review for drugs that may increase bleeding risk.
• Pregnancy and lactation: use only if clearly needed after risk‑benefit assessment.
• Store at ambient temperature: keep below 25 °C, in the original packaging, protected from moisture and direct sunlight.

Metamizole can interact with several drug classes; interactions vary in clinical significance.

Major Interactions (Avoid)

• Anticoagulants (e.g., warfarin): increased risk of bleeding.
• Methotrexate: enhanced toxicity due to reduced renal clearance.
• Cyclosporine: potential for nephrotoxicity.

Moderate Interactions (Monitor Closely)

• NSAIDs: additive gastrointestinal irritation.
• Lithium: possible increase in lithium serum levels.
• ACE inhibitors or ARBs: monitor renal function and potassium levels.