Metamizole Kabi (Metamizole Sodium Monohydrate)

Metamizole is a pyrazolone analgesic used for conditions involving acute pain, fever, and spasm‑related discomfort.

• Acute pain: provides rapid analgesia for sudden severe pain episodes.
• Post‑operative pain: reduces pain intensity after surgical procedures.
• Fever: lowers elevated body temperature in febrile states.
• Colic and spasm‑related pain: relaxes smooth muscle and alleviates visceral cramping.

• Metamizole exerts its effect by non‑selectively inhibiting cyclooxygenase (COX‑1 and COX‑2) enzymes, leading to decreased synthesis of prostaglandins that mediate pain, fever and inflammation. In addition, it acts centrally to modulate pain pathways and possesses spasmolytic activity on smooth muscle, contributing to its antispasmodic properties. The reduced prostaglandin levels also diminish peripheral sensitization, while central actions involve inhibition of nociceptive transmission in the spinal cord.

Metamizole may be associated with a range of adverse reactions, varying from mild to potentially life‑threatening.

Common Side Effects

• Injection site pain: mild discomfort at the site of administration.
• Transient hypotension: short‑lasting drop in blood pressure after injection.
• Nausea: feeling of sickness or urge to vomit.
• Dizziness: light‑headedness or balance disturbance.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction of white blood cells, increasing infection risk.
• Neutropenia: marked decrease in neutrophil count, requiring monitoring.
• Anaphylactic reaction: sudden, severe allergic response that can be fatal.
• Stevens‑Johnson syndrome: rare skin disorder with blistering and detachment.

When using Metamizole, several safety considerations should be observed to minimize risk.

• Renal impairment: monitor kidney function and adjust use as necessary.
• Hepatic dysfunction: use with caution in patients with liver disease.
• History of blood dyscrasias: avoid in individuals with prior agranulocytosis or severe neutropenia.
• Concurrent myelosuppressive therapy: closely monitor blood counts when combined with other bone‑marrow suppressors.
• Pregnancy and lactation: safety not established; avoid unless benefit outweighs risk.
• Store at ambient temperature: keep in original container, protect from light and moisture.

Metamizole can interact with other medicines, affecting its safety or efficacy.

Major Interactions (Avoid)

• Bone‑marrow suppressors: combined use heightens risk of agranulocytosis.
• Sulfonamide antibiotics: may increase incidence of blood dyscrasias.
• ACE inhibitors: can potentiate hypotensive effects.

Moderate Interactions (Monitor Closely)

• Non‑steroidal anti‑inflammatory drugs: additive gastrointestinal irritation.
• Anticoagulants: potential increase in bleeding tendency.
• Cytotoxic chemotherapy: enhanced myelosuppression risk.