Metamizole Sodium Kalceks (Metamizole Sodium Monohydrate)

• Metamizole sodium is employed as an analgesic and antipyretic, acting on the prostaglandin synthesis pathway to relieve discomfort and reduce fever.
• Pain: provides rapid relief of moderate to severe acute pain, including musculoskeletal, visceral and headache pain, facilitating functional improvement.
• Fever: effectively lowers elevated body temperature in febrile conditions such as infection or inflammation, improving patient comfort and reducing metabolic demand.
• Postoperative pain: manages surgical pain during the immediate postoperative period, allowing better mobilization and decreasing the need for additional opioid analgesics.

• Metamizole sodium exerts its analgesic and antipyretic actions by non‑selectively inhibiting cyclooxygenase enzymes, which reduces the synthesis of prostaglandins involved in pain signaling and thermoregulation. The decreased prostaglandin levels diminish peripheral nociceptor sensitization and central fever pathways, resulting in relief of pain and reduction of body temperature. Additionally, the drug may modulate central nervous system pathways that contribute to its overall therapeutic effect.

Metamizole sodium may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Hypotension: transient drop in blood pressure after injection.
• Nausea: mild to moderate feeling of stomach upset.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Injection site pain: local discomfort at the site of administration.
• Sweating: increased perspiration following dosing.
• Headache: mild to moderate head pain.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells that can lead to infection.
• Severe allergic reactions: including anaphylaxis, rash, and angioedema.
• Stevens‑Johnson syndrome: rare skin and mucous membrane disorder.
• Hepatic or renal failure: significant impairment of liver or kidney function.

• When using Metamizole sodium, several precautionary measures should be observed to minimize risk.
• Renal function assessment: evaluate kidney function before initiating therapy.
• Blood count monitoring: perform regular complete blood counts to detect early agranulocytosis.
• Hypersensitivity screening: avoid use in patients with known allergy to pyrazolones.
• Hepatic impairment caution: adjust or avoid in severe liver disease.
• Concomitant anticoagulant use: monitor for increased bleeding risk.
• Store at ambient temperature: keep in original packaging, protect from moisture and light.

Metamizole sodium can interact with several medicines, influencing efficacy or safety.

Major Interactions (Avoid)

• Anticoagulants: may potentiate bleeding risk.
• Methotrexate: increased toxicity due to reduced clearance.
• Lithium: altered serum levels leading to toxicity.

Moderate Interactions (Monitor Closely)

• NSAIDs: additive gastrointestinal irritation.
• ACE inhibitors: possible reduction in renal function when combined.