Generic Information

Zanaflex, also known by its generic name tizanidine, is a prescription medication. It is a short-acting muscle relaxant. Primary use is to treat spasticity, a condition where muscles are stiff and movements are awkward.

Dosage Form

Available in both tablet and capsule form. Tablet strength includes 2 mg and 4 mg. Capsules come in strengths of 2 mg, 4 mg, and 6 mg. Each form releases the medication differently in the body.

Administration Guidelines

Typically taken orally. Can be taken with or without food. Consistency in taking it with or without food is crucial, as food alters absorption. Follow physician instructions strictly regarding timing and dosage.

Pharmacokinetic Properties

Absorption is rapid and extensive from the gastrointestinal tract. Peak plasma concentrations are reached within approximately 1 hour. The half-life of the drug is about 2.5 hours. Primarily metabolized in the liver.

Mechanism of Action

Works by blocking nerve impulses, or pain sensations, that are sent to the brain. Specifically, it acts on alpha-2 adrenergic agonists in the central nervous system to inhibit motor neurons.

Indications

Primarily indicated for the management of spasticity. Spasticity, often resulting from multiple sclerosis or spinal cord injuries, benefits from the muscle-relaxant properties of tizanidine. Use is not limited to these conditions alone.

Contraindications

Contraindicated in patients with hypersensitivity to tizanidine. Should not be used in individuals who are concurrently on ciprofloxacin or fluvoxamine. These medications can increase the concentration of tizanidine in the bloodstream dangerously.

Adverse Reactions

Includes but is not limited to dizziness, dry mouth, drowsiness, and fatigue. Other side effects may include hypotension, bradycardia. Rarely, may cause hallucinations. Immediate medical attention is required if severe effects occur.

Drug Interactions

Potentially serious interaction with ciprofloxacin, fluvoxamine, and other CYP1A2 inhibitors due to increased plasma concentration. Alcohol increases sedative effects. Other central nervous system depressants may exacerbate side effects.

Special Populations

Renal Impairment

Dosage should be adjusted in patients with renal impairment. Such patients are at a greater risk of side effects due to decreased clearance.

Hepatic Impairment

Securing regular liver function tests is advisable for patients with hepatic impairment. They should exercise caution due to extensive liver metabolism of the drug.

Elderly Population

Dosage should be cautiously monitored. The elderly are more susceptible to the drug’s sedative and hypotensive effects.

Pediatric Use

The safety and effectiveness of tizanidine in pediatric patients have not been established. Therefore, it is generally not recommended for use in this population.

Dosage Adjustments

Adjustments should be made based on individual response and tolerability. Initiate therapy with low doses and gradually increase. Standard starting dose is 2 mg, consumed up to three times a day. Maximum single dose should not exceed 12 mg. The total daily dose should not exceed 36 mg.

Missed Dose

If a dose is missed, take it as soon as remembered. If it is near the time for the next dose, skip the missed dose. Do not double doses to make up for a missed dose.

Storage Conditions

Store at room temperature, between 20°C and 25°C (68°F and 77°F). Protect from light and moisture. Keep out of reach of children.

Monitoring

Regular monitoring of blood pressure is recommended due to risk of hypotension. Periodic liver function tests are suggested for patients on long-term therapy.

Overdose Management

Symptoms of overdose include hypotension, bradycardia, and respiratory depression. Immediate medical attention is required. Supportive measures and symptomatic treatment are essential.