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• Clinical Info

Uses

Spasticity

Management of spasticity associated with cerebral or spinal injury, alone or in conjunction with other standard therapies (e.g., baclofen).

Dosage and Administration

General

• Individualize dosage according to the patient’s requirements and response using the lowest dosage that produces optimum response without adverse effects.

Administration

Oral Administration

Clinically important differences (e.g., increased adverse effects, delayed or more rapid onset of activity) may be apparent when switching administration of capsules or tablets between fed and/or fasting states, switching between capsules and tablets in fed state, or switching between administration of intact capsule and sprinkling capsule contents on applesauce. Be thoroughly familiar with possible pharmacokinetic changes associated with these conditions. (See Absorption under Pharmacokinetics.)

Dosage

Available as tizanidine hydrochloride; dosage expressed in terms of tizanidine.

Adults

Spasticity

Oral

Initially, 4 mg; single doses <8 mg not effective in clinical trials, but 4-mg dose used to minimize the incidence of common dose-related adverse effects (e.g., orthostatic hypotension).

Repeat 4-mg dose every 6–8 hours as needed for a maximum of 3 doses in 24 hours.

Increase dosage gradually in increments of 2–4 mg daily over a period of 2–4 weeks until optimum therapeutic effects are obtained with tolerable adverse effects.

Prescribing Limits

Adults

Spasticity

Oral

Maximum 36 mg in a 24-hour period.

Special Populations

Renal Impairment

Initiate with caution in patients with renal impairment (Cl_cr <25 mL/minute). In these patients, use smaller individual doses during dosage titration; if higher doses are needed, increase the amount of each individual dose rather than increasing the frequency of dosing.

Cautions

Contraindications

Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.

• Concomitant therapy with fluvoxamine. (See Specific Drugs under Interactions.)
• Known hypersensitivity to tizanidine or any ingredient in the formulation.

Warnings/Precautions

Warnings

Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.

Cardiovascular Effects

Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.

Hypotension, occasionally associated with bradycardia, orthostatic effects, dizziness, and, rarely, syncope.

Minimize risk of marked hypotension by careful dosage titration; observe patients for manifestations of hypotension prior to dosage adjustment. Use caution in patients receiving concomitant antihypertensive therapy. (See Interactions.)

Hepatic Effects

Elevations (i.e., >3 times ULN, or 2 times ULN if baseline levels were elevated) of ALT or AST. In patients with elevated aminotransferase concentrations, nausea, vomiting, anorexia, and jaundice occasionally have been reported.

Monitor serum aminotransferase concentrations prior to and during the first 6 months of treatment (e.g., at baseline and at 1, 3, and 6 months) and periodically thereafter.

CNS Effects

Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.

Dose-related somnolence, sometimes severe.

Potential hallucinations generally occurring within the first 6 weeks of therapy. Psychoses associated with hallucinations reported in at least one patient.

General Precautions

Cardiovascular Effects

Pending revision, the material in this section should be considered in light of more recently available information in the MEDWATCH notification at the beginning of this monograph.

Potential for prolongation of the QT interval and bradycardia based on animal studies.

Pulse rate reduction in association with decreases in blood pressure has been reported.

Ocular Effects

Dose-related retinal degeneration and corneal opacities in animal studies.

Discontinuance of Therapy

Possible rebound manifestations with abrupt withdrawal of therapy, including hypertension, tachycardia, hypertonia, tremor, and anxiety.

If therapy is to be discontinued, decrease dosage gradually, particularly in patients who have been receiving high dosages for prolonged periods, to minimize the risk of withdrawal and rebound symptoms.

Specific Populations

Pregnancy

Category C.

Lactation

Not known whether tizanidine is distributed into milk. However, because it is lipid-soluble, tizanidine might be expected to pass into milk. Use caution in nursing women.

Pediatric Use

Safety and efficacy not established.

Geriatric Use

Clearance is decreased 4-fold; use with caution.

Hepatic Impairment

Use only with extreme caution in patients with impaired hepatic function. (See Hepatic Effects under Cautions.)

Renal Impairment

Clearance is reduced by >50% in patients with a Cl_cr <25 mL/minute. Use caution in patients with renal impairment. (See Renal Impairment under Dosage and Administration.)

Common Adverse Effects

Dry mouth, somnolence, asthenia (weakness, fatigue, and/or tiredness), dizziness.