What is the use of Tizanidine (Zanaflex)?

From the Guidelines

Tizanidine is recommended for the treatment of acute low back pain due to its moderate superiority to placebo for short-term pain relief, as evidenced by a higher-quality Cochrane review 1. The medication works by acting as an alpha-2 adrenergic agonist in the central nervous system, blocking nerve impulses that send pain sensations to the brain. Key points to consider when prescribing tizanidine include:

• Starting dose: 2-4 mg taken by mouth every 6-8 hours as needed
• Maximum daily dose: 36 mg
• Common side effects: drowsiness, dizziness, dry mouth, and weakness
• Potential interactions: blood pressure medications and CYP1A2 inhibitors like ciprofloxacin or fluvoxamine, which can increase tizanidine levels
• Contraindications: abrupt cessation after long-term use, as this may cause withdrawal symptoms It is essential to inform patients about these factors and monitor their response to the medication to minimize adverse events and maximize benefits. According to the evidence, skeletal muscle relaxants, including tizanidine, are associated with a higher total number of adverse events and central nervous system adverse events compared to placebo 1. However, the benefits of tizanidine for acute low back pain, as demonstrated in 8 trials, outweigh the risks, making it a viable treatment option 1.

From the FDA Drug Label

Tizanidine is a short-acting drug for the management of spasticity. The main use of tizanidine is for the management of spasticity.

• It is a short-acting drug, meaning its effects last for a limited time.
• Treatment with tizanidine should be used when relief of spasticity is most important 2

From the Research

Overview of Tizanidine

• Tizanidine is a central alpha 2 adrenoceptor agonist used in the treatment of spasticity in patients with cerebral or spinal injury 3.
• It is a myotonolytic agent with a wide interpatient variability in effective plasma concentrations, requiring dosage titration over 2 to 4 weeks for each patient 3.

Efficacy of Tizanidine

• Tizanidine has been shown to be effective in reducing mean muscle tone scores by 21 to 37% compared to 4 to 9% for placebo 3.
• It has also been found to be effective in reducing spasm frequency and clonus 3.
• Comparative studies have demonstrated that tizanidine has similar efficacy to baclofen and diazepam in the management of spasticity 4, 5.

Tolerability and Safety of Tizanidine

• The most common adverse effects associated with tizanidine are dry mouth and somnolence/drowsiness 3.
• Tizanidine has been found to have a more favorable tolerability profile compared to baclofen and diazepam, with less subjective muscle weakness reported by patients 3, 4.
• Global tolerability of tizanidine has been assessed as good to excellent in 44 to 100% of patients, compared to 38 to 90% for baclofen and 20 to 54% for diazepam 3.

Clinical Use of Tizanidine

• Tizanidine is widely used to manage spasticity secondary to conditions such as multiple sclerosis, stroke, and spinal cord injury 6.
• It can be used as monotherapy or in combination with other antispastic agents, such as baclofen, to effectively control spasticity while managing dose-dependent adverse events 6.
• The pharmacokinetics of tizanidine are dosage form-dependent, and it has a short-acting duration of action with linear pharmacokinetics 6.