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Tizanidne Hydrochloride

FDA Drug Information • Also known as: Tizanidne Hydrochloride

Brand Names
Tizanidne Hydrochloride
Route
ORAL
Dosage Form
CAPSULE
Product Type
HUMAN PRESCRIPTION DRUG

Description

11 DESCRIPTION Tizanidine capsules contains tizanidine hydrochloride the active ingredient, which is a central alpha2-adrenergic agonist. Its chemical name is 5-chloro-4-(2-imidazolin-2-ylamino)-2,1,3-benzothiadiazole monohydrochloride. It has a molecular formula of C 9 H 8 ClN 5 S-HCl and a molecular weight of 290.2. Its structural formula is: Tizanidine hydrochloride is almost white to slightly yellow, crystalline powder. Tizanidine hydrochloride is slightly soluble in water and methanol; solubility in water decreases as the pH increases. Tizanidine capsules are for oral administration and contain 2, 4, or 6 mg tizanidine (equivalent to 2.29 mg, 4.58 mg, and 6.87 mg tizanidine hydrochloride USP, respectively), and the inactive ingredients sugar spheres, hypromellose and silicon dioxide. Each capsule shell contains FD and C Blue1, FD and C Red 3 (4 mg and 6 mg), gelatin and titanium dioxide. The 2 mg and 6 mg capsule is printed with white pharmaceutical ink which contains shellac, propylene glycol, potassium hydroxide and titanium dioxide; 4 mg capsule is printed with black pharmaceutical ink which contains shellac, propylene glycol, black iron oxide and potassium hydroxide. tiz01

What Is Tizanidne Hydrochloride Used For?

1 INDICATIONS AND USAGE Tizanidine capsules are indicated for the treatment of spasticity in adults. Tizanidine capsules are a central alpha-2-adrenergic agonist indicated for the treatment of spasticity. ( 1 )

Dosage and Administration

2 DOSAGE AND ADMINISTRATION

  • Monitoring of aminotransferase levels is recommended at baseline and 1 month after maximum dose is achieved. ( 2.1 )
  • Recommended starting dose: 2 mg by mouth every 6 to 8 hours, as needed, up to a maximum of 3 doses in 24 hours ( 2.2 )
  • Dosage can be increased by 2 mg to 4 mg per dose every 1 to 4 days; maximum total daily dosage is 36 mg ( 2.2 )
  • 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. Consistent administration with respect to food is recommended. If substitution between dosage forms is necessary, take into consideration these pharmacokinetic differences. ( 2.2 , 2.6 , 12.3 )
  • Patients with renal impairment (creatinine clearance less than 25 mL/min) or hepatic impairment: use lower individual doses during titration. If higher doses are required, individual doses rather than dosing frequency should be increased. ( 2.3 , 2.4 )
  • To discontinue tizanidine capsules, decrease dose slowly to minimize the risk of withdrawal adverse reactions ( 2.5 ) 2.1 Recommended Evaluation and Testing Before and After Initiating Tizanidine Capsules Monitoring of aminotransferase levels is recommended at baseline and 1 month after maximum dose is achieved [see Warnings and Precautions ( 5.2 )]. 2.2 Recommended Dosage The recommended starting dose is 2 mg by mouth every 6 to 8 hours, as needed, to a maximum of three doses in 24 hours. Dosage can be gradually increased every 1 to 4 days by 2 mg to 4 mg at each dose based on clinical response and tolerability. The maximum total daily dosage is 36 mg. Single doses greater than 16 mg have not been studied. There are pharmacokinetic differences when administering tizanidine capsule between the fed or fasted state [see Clinical Pharmacology ( 12.3 )]. Tizanidine capsules may be taken with or without food; however, consistent administration with respect to food is recommended to reduce variability in tizanidine plasma exposure. Because of the short duration of therapeutic effect, treatment with tizanidine capsules should be reserved for those daily activities and times when relief of spasticity is most important. 2.3 Recommended Dosage in Patients with Renal Impairment In patients with creatinine clearance less than 25 mL/min, use lower individual doses during titration. If higher doses are required, the individual doses rather than dosing frequency should be increased [see Use in Specific Populations ( 8.6 ) and Clinical Pharmacology ( 12.3 )]. 2.4 Recommended Dosage in Patients with Hepatic Impairment In patients with hepatic impairment, use lower individual doses during titration. If higher doses are required, individual doses rather than dosing frequency should be increased [see Use in Specific Populations ( 8.7 ) and Clinical Pharmacology ( 12.3) ]. 2.5 Discontinuation of Tizanidine Capsules When discontinuing tizanidine capsule,...

    • Side Effects (Adverse Reactions)

    6 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 Ascend Laboratories, LLC at 1-877-272-7901 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. 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 (greater than 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 greater than 2% of Patients Treated with Tizanidine Tablets and Incidence Greater than Placebo Adverse Reaction Placebo N = 261% Tizanidine Tablet 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) Less than 1 3 Urinary frequency 2 3 Flu syndrome 2 3 Dyskinesia 0 3 Nervousness Less than 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...

    • Drug Interactions

    7 DRUG 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 ) 7.1 Strong 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 )]. 7.2 Moderate 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 )]. 7.3 Oral 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 )]. 7.4 Alcohol 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 α2-Adrenergic Agonists Concomitant use of tizanidine with other α2-adrenergic agonists is not recommended because hypotensive effects may be cumulative [see Warnings and Precautions ( 5.1 )]. 7.6 Antihypertensive Medications Concomitant use of tizanidine with antihypertensive medications may cause additive hypotensive effects [see Warnings and Precautions ( 5.1 )]. Monitor patients who take tizanidine with antihypertensive medications for hypotension.

    Contraindications

    4 CONTRAINDICATIONS Tizanidine capsules are contraindicated in patients:

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

    • Pregnancy and Breastfeeding

    8.1 Pregnancy Risk Summary There are no adequate data on the developmental risk associated with use of tizanidine in pregnant women. In animal studies, administration of tizanidine during pregnancy resulted in developmental toxicity (embryofetal and postnatal offspring mortality and growth deficits) at doses less than those used clinically, which were not associated with maternal toxicity (see Animal Data ). In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Data Animal Data Oral administration of tizanidine (0.3 to 100 mg/kg/day) to pregnant rats during the period of organogenesis resulted in embryofetal and postnatal offspring mortality and reductions in body weight at doses of 30 mg/kg/day and above. Maternal toxicity was observed at the highest dose tested. The no-effect dose for embryofetal developmental toxicity in rats (3 mg/kg/day) is similar to the maximum recommended human dose (MRHD) of 36 mg/day on a body surface area (mg/m 2 ) basis. Oral administration of tizanidine (1 to 100 mg/kg/day) to pregnant rabbits during the period of organogenesis resulted in embryofetal and postnatal offspring mortality at all doses. Maternal toxicity was observed at the highest dose tested. Oral administration of tizanidine (10 and 30 mg/kg/day) during the perinatal period of pregnancy (2 to 6 days prior to delivery) resulted in increased postnatal offspring mortality at both doses. A no-effect dose for embryofetal developmental toxicity in rabbit was not identified. The lowest dose tested (1 mg/kg/day) is less than the MRHD on a mg/m 2 basis. In a pre- and postnatal development study in rats, oral administration of tizanidine (3 to 30 mg/kg/day) resulted in increased postnatal offspring mortality. A no-effect dose for pre- and postnatal...

    8.3 Females and Males of Reproductive Potential There are no adequate and well-controlled studies in humans on the effect of tizanidine on female or male reproductive potential. Oral administration of tizanidine to male and female rats resulted in adverse effects on fertility [see Nonclinical Toxicology ( 13.1 )].

    Overdosage

    10 OVERDOSAGE A review of the safety surveillance database revealed cases of intentional and accidental tizanidine overdose. Some of the cases resulted in fatality and many of the intentional overdoses were with multiple drugs, including CNS depressants. The clinical manifestations of tizanidine overdose were consistent with its known pharmacology. In the majority of cases, a decrease in sensorium was observed including lethargy, somnolence, confusion, and coma. Depressed cardiac function is also observed including most often bradycardia and hypotension. Respiratory depression is another common feature of tizanidine overdose. Should overdose occur, ensure the adequacy of an airway and monitor cardiovascular and respiratory function. Dialysis is not likely to be an efficient method of removing tizanidine from the body [see Description (11)]. In general, symptoms resolve within one to three days following discontinuation of tizanidine and administration of appropriate therapy. Because of the similar mechanism of action, symptoms and management of tizanidine overdose are similar to that following clonidine overdose. For the most recent information concerning the management of overdose, contact a poison control center.

    How Supplied

    16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied Tizanidine capsules

  • 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 20 capsules (NDC 68788-8798-2) bottle of 30 capsules (NDC 68788-8798-3) bottle of 60 capsules (NDC 68788-8798-6) bottle of 90 capsules (NDC 68788-8798-9) bottle of 100 capsules (NDC 68788-8798-1) bottle of 120 capsules (NDC 68788-8798-8) 16.2 Storage and Handling Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Dispense in containers with child resistant closure.

    • About This Information

    This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

    What are side effects?

    Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

    What are drug interactions?

    Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.