Tizanidine

Tizanidine Tablets, USP is a central alpha-2-adrenergic agonist indicated for the management of spasticity. Because of the short duration of therapeutic effect, treatment with Tizanidine Tablets, USP should be reserved for those daily activities and times when relief of spasticity is most important [see Dosage and Administration(2.1) ]. Tizanidine Tablets, USP is a central alpha-2-adrenergic agonist indicated for the management of spasticity. Because of the short duration of therapeutic effect, treatment with Tizanidine Tablets, USP should be reserved for those daily activities and times when relief of spasticity is most important [ see Dosage and Administration (1) ].

• 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 • 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 • 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 • To discontinue Tizanidine Tablets, USP, decrease dose slowly to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia Dosing Information Tizanidine Tablets, USP tablets 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 Capsules and Tizanidine Tablets, USP 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. …

Tizanidine Tablets, USP 2 mg are white to off-white, round, flat beveled, uncoated tablets debossed with product code “502” on one side, and bisecting score on the other. Tizanidine Tablets, USP 4 mg are white to off-white, round, flat beveled, uncoated tablets debossed with product code “503” on one side, and quadrisecting score on the other. Tablets 2 mg and 4 mg. ( 3 )

• Safety and effectiveness
• In pediatric patients have not been established

Tizanidine Tablets, USP is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. …

• Serious Drug Interactions Advise patients they should not take Tizanidine Tablets, USP if they are taking fluvoxamine or ciprofloxacin because of the increased risk of serious adverse reactions including severe lowering of blood pressure and sedation
• Instruct patients to inform their physicians or pharmacists when they start or stop taking any medication because of the risks associated with interaction between Tizanidine Tablets, USP and other medicines
• Tizanidine Tablets, USP Dosing Tell patients to take Tizanidine Tablets, USP exactly as prescribed (consistently either with or without food) and not to switch between tablets and capsules. …

• Tizanidine Tablets, USP is contraindicated in patientstaking potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin [ see Drug Interactions ]
• Concomitant use with potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin

7.1 Fluvoxamine Concomitant use of fluvoxamine and Tizanidine Tablets, USP 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 ciprofoxacin and Tizanidine Tablets, USP is contraindicated. Changes in pharmacokinetics of tizanidine when administered with ciprofloxacin resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment. …

• Hypotension: monitor for signs and symptoms of hypotension, in particular in patients receiving concurrent antihypertensives; Tizanidine Tablets, USP should not be used with other α 2 -adrenergic agonists ( 5.1 , 7.7 ) • Risk of liver injury: monitor ALTs; discontinue Tizanidine Tablets, USP if liver injury occurs ( 5.2 ) • Sedation: Tizanidine Tablets, USP may interfere with everyday activities; sedative effects of Tizanidine Tablets, USP, alcohol, and other CNS depressants are additive ( 5.3 , 7.5 , 7.6 ) • Hallucinations: consider discontinuation of Tizanidine Tablets, USP ( 5.4 ) • Less potent inhibitors of CYP1A2: may cause hypotension, bradycardia, or excessive drowsiness, use cautio …

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 …

8.1 Pregnancy Pregnancy Category C Tizanidine Tablets, USP has not been studied in pregnant women. Tizanidine Tablets, USP should be given to pregnant women only if the benefit outweighs the risk to the unborn fetus. Reproduction studies performed in rats at a dose of 3 mg/kg, equal to the maximum recommended human dose on a mg/m 2 basis, and in rabbits at 30 mg/kg, 16 times the maximum recommended human dose on a mg/m 2 basis, did not show evide …

A review of the safety surveillance database revealed cases of intentional and accidental Tizanidine Tablets, USP 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. …

9.2 Abuse Abuse potential was not evaluated in human studies. Rats were able to distinguish tizanidine from saline in a standard discrimination paradigm, after training, but failed to generalize the effects of morphine, cocaine, diazepam, or phenobarbital to tizanidine. 9.3 Dependence Tizanidine is closely related to clonidine, which is often abused in combination with narcotics and is known to cause symptoms of rebound upon abrupt withdrawal. …

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.