✅ Uses & Indications
1 INDICATIONS AND USAGE Tizanidine hydrochloride is indicated for the management of spasticity. Because of the short duration of therapeutic effect, treatment with tizanidine hydrochloride should be reserved for those daily activities and times when relief of spasticity is most important [see Dosage and Administration ( 2.1 )]. Tizanidine hydrochloride is a central alpha-2-adrenergic agonist indicated for the management of spasticity. Because of the short duration of therapeutic effect, treatment with tizanidine hydrochloride capsules should be reserved for those daily activities and times when relief of spasticity is most important. ( 1 )
📏 Dosage & Administration
2 DOSAGE AND ADMINISTRATION Recommended starting dose: 2 mg; dose can be repeated at 6- to 8-hour intervals, up to a maximum of 3 doses in 24 hours ( 2.1 ) Dosage can be increased by 2 mg to 4 mg per dose, with 1 to 4 days between increases; total daily dose should not exceed 36 mg ( 2.1 ) Tizanidine pharmacokinetics differs between tablets and capsules, and when taken with or without food. These differences could result in a change in tolerability and control of symptoms ( 2.1 , 12.3 ) To discontinue tizanidine hydrochloride capsules, decrease dose slowly to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia ( 2.2 ) 2.1 Dosing Information Tizanidine hydrochloride capsules may be prescribed with or without food. Once the formulation has been selected and the decision to take with or without food has been made, this regimen should not be altered. Food has complex effects on tizanidine pharmacokinetics, which differ with the different formulations. Tizanidine hydrochloride capsules and tizanidine tablets are bioequivalent to each other under fasting conditions (more than 3 hours after a meal), but not under fed conditions (within 30 minutes of a meal). These pharmacokinetic differences may result in clinically significant differences when switching administration of tablet and capsules and when switching administration between the fed or fasted state. These changes may result in increased adverse events, or delayed or more rapid onset of activity, depending upon the nature of the switch. For this reason, the prescriber should be thoroughly familiar with the changes in kinetics associated with these different conditions [see Clinical Pharmacology ( 12.3 )]. The recommended starting dose is 2 mg. Because the effect of tizanidine hydrochloride capsule peaks at approximately 1 to 2 hours post-dose and dissipates between 3 to 6 hours post-dose, treatment can be repeated at 6 to 8 hour intervals, as needed, to a maximum of three doses in 24 hours. Dosage can be gradually increased by 2 mg to 4 mg at each dose, with 1 to 4 days between dosage increases, until a satisfactory reduction of muscle tone is achieved. The total daily dose should not exceed 36 mg. Single doses greater than 16 mg have not been studied. 2.2 Dosing in Patients with Renal Impairment Tizanidine hydrochloride capsules should be used with caution in patients with renal insufficiency (creatinine clearance < 25 mL/min), as clearance is reduced by more than 50%. In these patients, during titration, the individual doses should be reduced. If higher doses are required, individual doses rather than dosing frequency should be increased [see Warnings and Precautions ( 5.7 )]. 2.3 Dosing in Patients with Hepatic Impairment Tizanidine hydrochloride capsules should be used with caution in patients with any hepatic impairment. In these patients, during titration, the individual doses should be reduced. If higher doses are required, individual doses rather than dosing frequency should be increased. Monitoring of aminotransferase levels is recommended for baseline and 1 month after maximum dose is achieved, or if hepatic injury is suspected [see Use in Specific Populations ( 8.7 )]. 2.4 Drug Discontinuation If therapy needs to be discontinued, particularly in patients who have been receiving high doses (20 mg to 36 mg daily) for long periods (9 weeks or more) or who maybe on concomitant treatment with narcotics, the dose should be decreased slowly (2 mg to 4 mg per day) to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia [see Drug Abuse and Dependence ( 9.3 )].
💊 Side Effects
6 ADVERSE REACTIONS The following 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 ( 5.6 )] The most common adverse reactions (greater than 2% of 264 patients taking tizanidine and greater than in placebo-treated patients in three multiple dose, placebo-controlled studies) were dry mouth, somnolence, asthenia, dizziness, urinary tract infection, constipation, liver function tests abnormal, vomiting, speech disorder, amblyopia, urinary frequency, flu syndrome, SGPT/ALT increased, dyskinesia, nervousness, pharyngitis, and rhinitis ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Ascend Laboratories, LLC at 1-877-ASC-RX01 (877-272-7901) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical 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. Three double-blind, randomized, placebo-controlled clinical studies were conducted to evaluate the effect of tizanidine on spasticity control. 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. In all, 264 patients received tizanidine and 261 patients received placebo. Across the three studies patient ages ranged from 15 to 69 years and 51.4 percent were women. The median dose during the plateau phase ranged from 20 to 28 mg/day. The most frequent adverse reactions 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 events as mild to moderate and one-quarter of the patients rated the events as being severe. These events appeared to be dose related. Table 1 lists signs and symptoms 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. For comparison purposes, the corresponding frequency of the event (per 100 patients) among placebo treated patients is also provided. Table 1: Multiple Dose, Placebo-Controlled Studies—Frequent (>2%) Adverse Reactions Reported for Which Tizanidine Tablets Incidence is Greater than Placebo Event Placebo N = 261% Tizanidine Tablets N = 264% Dry mouth 10 49 Somnolence 10 48 Asthenia* 16 41 Dizziness 4 16 UTI 7 10 Infection 5 6 Constipation 1 4 Liver test abnormality 2 6 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 *(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 Event 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 *(weakness, fatigue, and/or tiredness) 6.2 Postmarketing 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. Certain events, such as somnolence, dry mouth, hypotension, decreased blood pressure, bradycardia, dizziness, weakness or asthenia, muscle spasms, hallucinations, fatigue, liver function test abnormality and hepatotoxicity, have been observed in post marketing and clinical trials and are discussed in previous sections of this document. The following adverse reactions have been identified as occurring in the post marketing experience of tizanidine. Based on the information provided regarding these reactions, a causal relationship with tizanidine cannot be entirely excluded. The events are listed in order of decreasing clinical significance; severity in the post marketing setting is not reported. Stevens Johnson Syndrome Anaphylactic Reaction Exfoliative Dermatitis Ventricular Tachycardia Hepatitis Convulsion Depression Arthralgia Paresthesia Rash Tremor
⚠️ Warnings & Precautions
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 α2-adrenergic agonists ( 5.1 , 7.7 ) 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 CNS depressants are additive ( 5.3, 7.5 , 7.6 ) Hallucinations: consider discontinuation of tizanidine ( 5.4 ) Less potent inhibitors of CYP1A2: may cause hypotension, bradycardia, or excessive drowsiness, use caution if tizanidine is used with less potent inhibitors of CYP1A2, e.g., zileuton, other fluoroquinolones, antiarrhythmics, cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine ( 5.5 , 7.3 , 12.3 ) Renal impairment (creatinine clearance < 25 mL/min): use tizanidine with caution, and monitor closely for dry mouth, somnolence, asthenia and dizziness as indicators of potential overdose ( 5.7 ) 5.1 Hypotension Tizanidine is an α2-adrenergic agonist that can produce hypotension. Syncope has been reported in the post marketing setting. The chance of significant hypotension may possibly be minimized by titration of the dose and by focusing attention on signs and symptoms of hypotension prior to dose advancement. 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 α2-adrenergic agonists. Clinically significant hypotension (decreases in both systolic and diastolic pressure) has been reported with concomitant administration of either fluvoxamine or ciprofloxacin and single doses of 4 mg of tizanidine. Therefore, concomitant use of tizanidine with fluvoxamine or with ciprofloxacin, potent inhibitors of CYP1A2, is contraindicated [see Contraindications ( 4 ) and Drug Interactions ( 7.1 , 7.2 )]. 5.2 Risk of Liver Injury Tizanidine may cause hepatocellular liver injury. Tizanidine should be used with caution in patients with any hepatic impairment. Monitoring of aminotransferase levels is recommended for baseline and 1 month after maximum dose is achieved, or if hepatic injury is suspected [see Dosage and Administration ( 2.3 ) and Use in Specific Populations ( 8.7 )]. 5.3 Sedation Tizanidine can cause sedation, which may interfere with everyday activity. In the multiple dose studies, the prevalence of patients with sedation peaked following the first week of titration and then remained stable for the duration of the maintenance phase of the study. The CNS depressant effects of tizanidine with alcohol and other CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants) may be additive. Monitor patients who take tizanidine with another CNS depressant for symptoms of excess sedation [see Drug Interactions ( 7.5, 7.6 )]. 5.4 Hallucinosis/Psychotic-Like Symptoms Tizanidine use has been associated with hallucinations. Formed, visual hallucinations or delusions have been reported in 5 of 170 patients (3%) in two North American controlled clinical studies. Most of the patients were aware that the events were unreal. One patient developed psychosis in association with the hallucinations. One patient among these 5 continued to have problems for at least 2 weeks following discontinuation of tizanidine. Consider discontinuing tizanidine in patients who develop hallucinations. 5.5 Interaction with CYP1A2 Inhibitors Because of potential drug interactions, tizanidine is contraindicated in patients taking potent CYP1A2 inhibitors, such as fluvoxamine or ciprofloxacin. Adverse reactions such as hypotension, bradycardia, or excessive drowsiness can occur when tizanidine is taken with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than ciprofloxacin (which is contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine). Concomitant use should be avoided unless the necessity for tizanidine therapy is clinically evident. In such a case, use with caution [see Drug Interactions ( 7.3 ) and Clinical Pharmacology ( 12.3 )]. 5.6 Hypersensitivity Reactions Tizanidine can cause anaphylaxis. Signs and symptoms including respiratory compromise, urticaria, and angioedema of the throat and tongue have been reported. Patients should be informed of the signs and symptoms of severe allergic reactions and instructed to discontinue tizanidine and seek immediate medical care should these signs and symptoms occur [see Contraindications ( 4 )]. 5.7 Increased Risk of Adverse Reactions in Patients with Renal Impairment Tizanidine should be used with caution in patients with renal insufficiency (creatinine clearance < 25 mL/min), as clearance is reduced by more than 50%. In these patients, during titration, the individual doses should be reduced. If higher doses are required, individual doses rather than dosing frequency should be increased. These patients should be monitored closely for the onset or increase in severity of the common adverse events (dry mouth, somnolence, asthenia and dizziness) as indicators of potential overdose [see Dosage and Administration (2.2) and Use in Specific Populations (8.6)]. 5.8 Withdrawal Adverse Reactions Withdrawal adverse reactions include rebound hypertension, tachycardia, and hypertonia. To minimize the risk of these reactions, particularly in patients who have been receiving high doses (20 to 28 mg daily) for long periods of time (9 weeks or more) or who may be on concomitant treatment with narcotics, the dose should be decreased slowly (2 to 4 mg per day) [see Dosage and Administration ( 2.2 )].
🔄 Drug Interactions
7 DRUG INTERACTIONS 7.1 Fluvoxamine Concomitant use of fluvoxamine and tizanidine is contraindicated. Changes in pharmacokinetics of tizanidine when administered with fluvoxamine resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 )]. 7.2 Ciprofloxacin Concomitant use of ciprofloxacin and tizanidine is contraindicated. Changes in pharmacokinetics of tizanidine when administered with ciprofloxacin resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 )]. 7.3 CYP1A2 Inhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of tizanidine with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided. If their use is clinically necessary, therapy should be initiated with 2 mg dose and increased in 2 to 4 mg steps daily based on patient response to therapy. If adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue tizanidine therapy [see Warnings and Precautions ( 5.5 ) and Clinical Pharmacology ( 12.3 )]. 7.4 Oral Contraceptives Concomitant use of tizanidine with oral contraceptives is not recommended. However, if concomitant use is clinically necessary, initiate tizanidine with a single 2 mg dose and increase in 2 to 4 mg steps daily based on patient response to therapy. If adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue tizanidine therapy [see Clinical Pharmacology ( 12.3 )]. 7.5 Alcohol Alcohol increases the overall amount of drug in the bloodstream after a dose of tizanidine. This was associated with an increase in adverse reactions of tizanidine. The CNS depressant effects of tizanidine and alcohol are additive [see Clinical Pharmacology ( 12.3 )]. 7.6 Other CNS Depressants The sedative effects of tizanidine with CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants) may be additive. Monitor patients who take tizanidine with another CNS depressant for symptoms of excess sedation [see Clinical Pharmacology ( 12.3 )]. 7.7 α 2 -Adrenergic Agonists Because hypotensive effects may be cumulative, it is not recommended that tizanidine be used with other α 2- adrenergic agonists [see Warnings and Precautions ( 5.1 )].
🚫 Contraindications
4 CONTRAINDICATIONS Tizanidine hydrochloride capsules is contraindicated in patients taking potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin [see Drug Interactions ( 7.1 , 7.2 )]. Concomitant use with potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin( 4 , 5.5 , 7.1 , 7.2 )
📦 Storage & Handling
16 HOW SUPPLIED/STORAGE AND HANDLING 6.1 Tizanidine hydrochloride capsules Tizanidine hydrochloride capsules are available in three strengths as two-piece hard gelatin capsules containing tizanidine hydrochloride 4.58 mg, equivalent to 4 mg tizanidine base. • Tizanidine capsules 4 mg have a hard gelatin capsule size "3" blue opaque cap, imprinted "4MG" with white ink and "Tiza" & white opaque body "circle of thin line" with black ink, containing light yellow to yellow color pellets. Tizanidine capsules 4 mg are supplied as follows. bottle of 150 capsules (NDC 63629-8872-1) Store at 25°C (77°F); excursions permitted to 15 to 30°C (59 to 86°F) [see USP Controlled Room Temperature]. Dispense in containers with child resistant closure. Repackaged/Relabeled by: Bryant Ranch Prepack, Inc. Burbank, CA 91504