Klorzoxazon Dak (Chlorzoxazone)

Chlorzoxazone acts on skeletal muscle spasm and related pain conditions.

• Muscle spasm: reduces painful involuntary muscle contractions and improves mobility.
• Acute musculoskeletal pain: alleviates pain associated with strains, sprains, and low‑back discomfort.
• Chronic musculoskeletal disorders: provides adjunctive relief when combined with physical therapy and other analgesics.

• Chlorzoxazone is a centrally acting muscle relaxant that likely inhibits neuronal activity within the spinal cord and brainstem, decreasing the transmission of reflex pathways that generate muscle spasm. Its exact molecular target is not fully defined, but the overall effect is a reduction in tonic muscle contraction and associated pain.

Adverse reactions may occur with chlorzoxazone therapy.

Common Side Effects

• Drowsiness: feeling unusually sleepy or fatigued.
• Dizziness: light‑headed sensation, especially upon standing.
• Nausea: upset stomach or urge to vomit.
• Headache: mild to moderate cranial pain.
• Gastrointestinal upset: abdominal discomfort or dyspepsia.
• Fatigue: reduced energy levels.

Serious or Rare Side Effects

• Hepatotoxicity: signs of liver injury such as jaundice or elevated enzymes.
• Severe skin reactions: rash, Stevens‑Johnson syndrome, or toxic epidermal necrolysis.
• Blood dyscrasias: unexplained bruising, anemia, or leukopenia.
• Anaphylaxis: sudden severe allergic reaction with airway compromise.
• Agranulocytosis: marked reduction in white blood cells, increasing infection risk.

Before initiating chlorzoxazone therapy, consider the following safety measures.

• Pregnancy: safety not established; avoid unless clearly needed.
• Liver disease: use with caution and monitor hepatic function.
• Alcohol consumption: may potentiate central nervous system depression.
• Elderly patients: increased susceptibility to sedation and falls; start at lower doses.
• Concomitant CNS depressants: monitor for additive sedation effects.
• Store at ambient temperature: keep in the original pack, protect from moisture.

Chlorzoxazone may interact with several drug classes, requiring vigilance.

Major Interactions (Avoid)

• CYP2E1 inhibitors (e.g., disulfiram): can increase chlorzoxazone plasma levels.
• CNS depressants (e.g., opioids, benzodiazepines): additive sedation and respiratory depression.
• Alcohol: enhances central nervous system depression.

Moderate Interactions (Monitor Closely)

• CYP2E1 inducers (e.g., rifampin): may reduce therapeutic effect.
• Anticoagulants (e.g., warfarin): potential for increased bleeding risk.
• Antihistamines: may heighten drowsiness and dizziness.