TIZANIDINE
It is centrally acting skeletal muscle relaxant; its major site of action is in the spinal cord .It preferentially inhibits polysynaptic mechanisms responsible for excessive muscle tone, mainly by reducing the release of excitatory amino acids from interneurons.It does not affect neuromuscular transmission.-Muscle spasticity associated with multiple sclerosis or spinal cord injury -Chronic painful muscle conditions
-Initial: 2 mg orally every 6 to 8 hours. -Maintenance: May increase gradually by 2-4 mg/day at intervals of 1-4 days until desired response is achieved. -Maximum dose: 36 mg/day in divided doses. -Painful muscle spasm :2mg 3 times daily. -Spasticity : daily dose should not exceed 6 mg.
-Hypersensitivity to tizanidine or any component of the formulation. -Concomitant use with potent CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin).
Renal insufficiency,impaired liver function,driving vehicle or operating machinery. Pregnancy: Contraindicated. Lactation: Contraindicated. Elderly: Use with caution.
-Drowsiness -Dizziness -Hypotension -Dry mouth -Weakness -Fatigue -Bradycardia -Hallucinations -Liver enzyme elevations -Urinary tract infection
-Potent CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin): Increased tizanidine levels and risk of hypotension and sedation. -Potent CYP1A2 inducers (e.g., rifampin): Decreased tizanidine levels and efficacy. -CNS depressants (e.g., alcohol, opioids): Enhanced sedative effects. -Antihypertensive agents: Additive hypotensive effects. -Oral contraceptives: Increased tizanidine levels.
