FDA

Tizanidine Hydrochloride

Approved 3 Feb 2012OralCapsule

The FDA lists this product in 60 strengths and forms.

Indications

Tizanidine is indicated for the treatment of spasticity in adults. Tizanidine is a central alpha-2-adrenergic agonist indicated for the treatment of spasticity. ( 1 )

Contraindications

Tizanidine is contraindicated in patients: taking strong CYP1A2 inhibitors [see Drug Interactions ( 7.1 )]. with a history of hypersensitivity to tizanidine or the ingredients in tizanidin e capsules. Symptoms have included anaphylaxis and angioedema [see Warnings and Precautions ( 5.5 )]. Concomitant use with strong of CYP1A2 inhibitors ( 4 , 7.1 ) Patients with a history of hypersensitivity to tizanidine or the ingredients in tizanidine capsules ( 4 , 5.5 )

Warnings and precautions

Hypotension: monitor for signs and symptoms of hypotension, in particular in patients receiving concurrent antihypertensives; tizanidine should not be used with other α 2 -adrenergic agonists ( 5.1 , 7.5 ) Risk of liver injury: monitor ALTs; discontinue tizanidine if liver injury occurs ( 5.2 ) Sedation: Tizanidine may interfere with everyday activities; sedative effects of tizanidine, alcohol, and other central nervous system (CNS) depressants are additive ( 5.3 , 7.4 ) Hallucinations: consider discontinuation of tizanidine ( 5.4 )

5.1Hypotension

Tizanidine is an α 2 -adrenergic agonist that can produce hypotension [see Adverse Reactions ( 6.1 ) and Drug Interactions ( 7.5 )] . Syncope has been reported in patients treated with tizanidine in the postmarketing setting. The risk of hypotension may be minimized by dose titration; monitoring for signs and symptoms of hypotension prior to dosage increase may minimize the risks associated with hypotension. In addition, patients moving from a supine to fixed upright position may be at increased risk for hypotension and orthostatic effects.

Monitor for hypotension when tizanidine is used in patients receiving concurrent antihypertensive therapy. It is not recommended that tizanidine be used with other α 2 -adrenergic agonists. Clinically significant hypotension (decreases in both systolic and diastolic pressure) has been reported with concomitant administration of tizanidine and strong CYP1A2 inhibitors [see Clinical Pharmacology ( 12.3 )] . Therefore, concomitant use of tizanidine with strong CYP1A2 inhibitors is contraindicated [see Contraindications ( 4 ) and Drug Interactions ( 7.1 )].

At a glance

Brand name: Tizanidine Hydrochloride
Route: Oral
Dosage form: Capsule
Applicant: Apotex Inc
Status: Prescription
FDA approval: 3 Feb 2012
Application: ANDA078868-001

Contraindications

Warnings and precautions

5.1Hypotension

Interactions

Moderate or weak CYP1A2 inhibitors: avoid concomitant use; may cause hypotension, bradycardia, or excessive drowsiness; if concomitant use is necessary and adverse reactions occur, reduce tizanidine dosage or discontinue. ( 7.2 , 12.3 )

7.1Strong CYP1A2 Inhibitors

Concomitant use of tizanidine with strong cytochrome P450 1A2 (CYP1A2) inhibitors (e.g., fluvoxamine, ciprofloxacin) is contraindicated. Changes in pharmacokinetics of tizanidine when administered with a strong CYP1A2 inhibitor resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 )].

7.2Moderate or Weak CYP1A2 Inhibitors

Concomitant use of tizanidine with moderate or weak CYP1A2 inhibitors (e.g., zileuton, antiarrhythmics [amiodarone, mexiletine, propafenone, and verapamil], cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided. If concomitant use is clinically necessary, and adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce tizanidine dosage or discontinue tizanidine therapy [see Clinical Pharmacology ( 12.3 )].

7.3Oral Contraceptives

Concomitant use of tizanidine with oral contraceptives is not recommended. However, if concomitant use is clinically necessary and adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue tizanidine therapy [see Clinical Pharmacology ( 12.3 )].

7.4Alcohol and Other CNS Depressants

Alcohol increases the exposure of tizanidine after administration of tizanidine. This was associated with an increase in adverse reactions of tizanidine. Concomitant use of tizanidine with CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may cause additive CNS depressant effects, including sedation. Monitor patients who take tizanidine with another CNS depressant for symptoms of excess sedation [see Clinical Pharmacology ( 12.3 )]. 7.5 α 2 -Adrenergic Agonists Concomitant use of tizanidine with other α 2 -adrenergic agonists is not recommended because hypotensive effects may be cumulative [see Warnings and Precautions ( 5.1 )].

7.6Antihypertensive Medications

Concomitant use of tizanidine capsules with antihypertensive medications may cause additive hypotensive effects [see Warnings and Precautions ( 5.1 )] . Monitor patients who take tizanidine with antihypertensive medications for hypotension.

Adverse reactions

The following clinically significant adverse reactions are described elsewhere in other sections of the prescribing information: Hypotension [see Warnings and Precautions ( 5.1 )] Liver Injury [see Warnings and Precautions ( 5.2 )] Sedation [see Warnings and Precautions ( 5.3 )] Hallucinosis/Psychotic-Like Symptoms [see Warnings and Precautions ( 5.4 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.5 )] Withdrawal Adverse Reactions [see Warnings and Precautions ( 5.6 )] The most common adverse reactions (greater than 10% of patients taking tizanidine and greater than in patients taking placebo) were dry mouth, somnolence, asthenia, and dizziness.

( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Apotex Corp. at 1-800-706-5575 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. The safety of tizanidine has been evaluated in three double-blind, randomized, placebo-controlled clinical studies [see Clinical Studies ( 14 )] .

Two studies were conducted in patients with multiple sclerosis and one in patients with spinal cord injury. Each study had a 13-week active treatment period which included a 3- week titration phase to the maximum tolerated dose up to 36 mg/day in three divided doses, a 9-week plateau phase where the dose of tizanidine was held constant and a 1-week dose tapering period. In all, 264 patients received tizanidine and 261 patients received placebo.

Across the three studies approximately 51% of patients were women, and the median dose during the plateau phase ranged from 20 to 28 mg/day. The most common adverse reactions (>10% of patients treated with tizanidine) reported in multiple dose, placebo-controlled clinical studies involving 264 patients with spasticity were dry mouth, somnolence/sedation, asthenia (weakness, fatigue and/or tiredness), and dizziness. Three-quarters of the patients rated the reactions as mild to moderate and one-quarter of the patients rated the reactions as being severe.

These adverse reactions appeared to be dose related. Table 1 lists adverse reactions that were reported in greater than 2% of patients in three multiple dose, placebo-controlled studies who received tizanidine where the frequency in the tizanidine group was greater than the placebo group. Table 1: Multiple Dose, Placebo-Controlled Studies—Adverse Reactions Reported in >2% of Patients Treated with Tizanidine Tablets and Incidence Greater than Placebo Placebo Tizanidine Tablet N = 261 N = 264 Adverse Reaction % % Dry mouth 10 49 Somnolence 10 48 Asthenia* 16 41 Dizziness 4 16 UTI 7 10 Infection 5 6 Liver test abnormality 2 6 Constipation 1 4 Vomiting 0 3 Speech disorder 0 3 Amblyopia (blurred vision) <1 3 Urinary frequency 2 3 Flu syndrome 2 3 Dyskinesia 0 3 Nervousness <1 3 Pharyngitis 1 3 Rhinitis 2 3 * includes weakness, fatigue, and/or tiredness In the single dose, placebo-controlled study involving 142 patients with spasticity due to multiple sclerosis (Study 1) [see Clinical Studies ( 14 )] , the patients were specifically asked if they had experienced any of the four most common adverse reactions: dry mouth, somnolence (drowsiness), asthenia (weakness, fatigue and/or tiredness), and dizziness.

In addition, hypotension and bradycardia were observed. The occurrence of these reactions is summarized in Table 2. Other events were, in general, reported at a rate of 2% or less. Table 2: Single Dose, Placebo-Controlled Study—Common Adverse Reactions Reported Adverse Reaction Placebo N = 48 % Tizanidine Tablet, 8 mg, N = 45 % Tizanidine Tablet, 16 mg, N = 49 % Somnolence 31 78 92 Dry mouth 35 76 88 Asthenia* 40 67 78 Dizziness 4 22 45 Hypotension 0 16 33 Bradycardia 0 2 10 * includes weakness, fatigue, and/or tiredness

6.2Postmarketing Experience

The following adverse reactions have been identified during post approval use of tizanidine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiac Disorders: Ventricular tachycardia, decreased blood pressure Hepatobiliary Disorders: Hepatotoxicity [see Warnings and Precautions ( 5.2 )] , hepatitis Musculoskeletal and Connective Tissue Disorders: arthralgia Nervous System Disorders: Convulsion, paresthesia, tremor, muscle spasms Psychiatric Disorders: Hallucinations [see Warnings and Precautions ( 5.4 )] , depression Skin and Subcutaneous Tissue Disorders: Stevens Johnson Syndrome, anaphylactic reaction [see Warnings and Precautions ( 5.5 )] , exfoliative dermatitis, rash

Tizanidine Hydrochloride

Indications

Contraindications

Warnings and precautions

5.1Hypotension

At a glance

Two medicines in one question?

Tizanidine Hydrochloride

Indications

Contraindications

Warnings and precautions

5.1Hypotension

At a glance

Two medicines in one question?

5.2Liver Injury

5.3Sedation

5.4Hallucinosis/Psychotic-Like Symptoms

5.5Hypersensitivity Reactions

5.6Withdrawal Adverse Reactions

Interactions

7.1Strong CYP1A2 Inhibitors

7.2Moderate or Weak CYP1A2 Inhibitors

7.3Oral Contraceptives

7.4Alcohol and Other CNS Depressants

7.6Antihypertensive Medications

Adverse reactions

6.1Clinical Trials Experience

6.2Postmarketing Experience

Composition

Strengths and forms

Official product information