Navizan (Tizanidine)

• Navizan (tizanidine) acts on the central nervous system to lessen abnormal muscle tone in several neurologic conditions.
• Multiple sclerosis spasticity: reduces muscle stiffness and improves functional movement.
• Spinal cord injury spasticity: diminishes involuntary muscle contractions and enhances mobility.
• Muscle spasm: provides rapid relief of acute skeletal muscle tightening.

• Tizanidine selectively stimulates presynaptic alpha‑2 adrenergic receptors in the spinal cord, inhibiting the release of excitatory neurotransmitters. This reduces the firing rate of motor neurons, leading to decreased muscle tone and alleviation of spasticity without directly affecting muscle fibers.

Tizanidine may cause a range of adverse reactions, from mild to serious.

Common Side Effects

• Dry mouth: sensation of oral dryness.
• Drowsiness: increased sleepiness or fatigue.
• Dizziness: light‑headed feeling, especially when standing.
• Weakness: reduced muscle strength.
• Hypotension: lowered blood pressure, may cause faintness.
• Fatigue: general lack of energy.

Serious or Rare Side Effects

• Severe hypotension: marked drop in blood pressure requiring medical attention.
• Hepatic injury: signs of liver dysfunction such as jaundice.
• Hallucinations or psychotic symptoms.
• Cardiac arrhythmias: irregular heart rhythms.
• Severe allergic reactions: rash, swelling, or breathing difficulty.
• Suicidal thoughts or behavior.

• Before initiating therapy, clinicians should consider several safety measures.
• Renal impairment: adjust dose in patients with reduced kidney function.
• Hepatic disease: use cautiously and monitor liver enzymes.
• Blood pressure monitoring: check regularly, especially after dose changes.
• Avoid abrupt discontinuation: taper to prevent rebound hypertension.
• Concurrent CNS depressants: limit use with alcohol or sedatives.
• Store at ambient temperature: keep in original container, protect from moisture and heat.

Tizanidine can interact with other medicines, altering its effectiveness or safety.

Major Interactions (Avoid)

• CYP1A2 inhibitors (e.g., cimetidine, fluvoxamine): may increase tizanidine levels.
• Fluoroquinolone antibiotics (e.g., ciprofloxacin): can cause profound hypotension.
• Antihypertensive agents (e.g., beta‑blockers): risk of additive blood‑pressure lowering.
• CNS depressants (e.g., alcohol, benzodiazepines): enhance sedation and dizziness.

Moderate Interactions (Monitor Closely)

• CYP1A2 inducers (e.g., rifampin, smoking): may reduce efficacy.
• Other muscle relaxants: monitor for excessive weakness.
• NSAIDs: watch for renal function changes when combined with diuretics.