Tizanidine Hcl
Tizanidine Hcl - General Information
Tizanidine Hcl is a short-acting drug for the management of spasticity. Tizanidine Hcl is an agonist at a2-adrenergic receptor sites and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. In animal models, tizanidine has no direct effect on skeletal muscle fibers or the neuromuscular junction, and no major effect on monosynaptic spinal reflexes. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons.
Pharmacology of Tizanidine Hcl
Tizanidine Hcl is a short-acting drug for the management of spasticity. Tizanidine Hcl is an agonist at a2-adrenergic receptor sites and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. In animal models, tizanidine has no direct effect on skeletal muscle fibers or the neuromuscular junction, and no major effect on monosynaptic spinal reflexes. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons.
Tizanidine Hcl for patients
Tizanidine Hcl Interactions
In vitro studies of cytochrome P450 isoenzymes using human liver microsomes indicate that neither tizanidine nor the major metabolites are likely to affect the metabolism of other drugs metabolized by cytochrome P450 isoenzymes.
Acetaminophen: Tizanidine delayed the Tmax of acetaminophen by 16 minutes. Acetaminophen did not affect the pharmacokinetics of tizanidine.
Alcohol: Alcohol increased the AUC of tizanidine by approximately 20% while also increasing its Cmax by approximately 15%. This was associated with an increase in side effects of tizanidine. The CNS depressant effects of tizanidine and alcohol are additive.
Fluvoxamine: Clinically significant hypotension (decreases in both systolic and diastolic pressure) has been reported with concomitant administration of fluvoxamine following single doses of 4 mg.
Caution is recommended when considering concomitant use of tizanidine with other inhibitors of CYP1A2, such as, antiarrhythmics (amiodarone, mexiletine, propafenone), cimetidine, fluoroquinolones (ciprofloxacin, norfloxacin), rofecoxib, oral contraceptives, and ticlopidine.
Oral Contraceptives: No specific pharmacokinetic study was conducted to investigate interaction between oral contraceptives and tizanidine, but retrospective analysis of population pharmacokinetic data following single and multiple dose administration of 4 mg tizanidine showed that women concurrently taking oral contraceptives had 50% lower clearance of tizanidine than women not on oral contraceptives.
Tizanidine Hcl Contraindications
Zanaflex is contraindicated in patients with known hypersensitivity to Zanaflex or its ingredients.
Concomitant use of Zanaflex with fluvoxamine, a potent inhibitor of cytochrome P-450 (CYP) 1A2, is contraindicated. Significant alterations of pharmacokinetic parameters of tizanidine including AUC, t½, and Cmax, increased oral bioavailability and decreased plasma clearance have been observed with concomitant fluvoxamine administration.
Additional information about Tizanidine Hcl
Tizanidine Hcl Indication: For the management of increased muscle tone associated with spasticity
Mechanism Of Action: Tizanidine Hcl reduces spasticity by increasing presynaptic inhibition of motor neurons through agonist action at a2-adrenergic receptor sites.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Tizanidine
Synonyms: Not Available
Drug Category: Muscle Relaxants; Anticonvulsants; Analgesics; Skeletal Muscle Relaxants
Drug Type: Small Molecule; Approved
Other Brand Names containing Tizanidine: Pramiracetam; Sirdalud; Ternelin; Tizanidina [Inn-Spanish]; Tizanidine Hcl; Tizanidinum [Inn-Latin]; Zanaflex;
Absorption: Not Available
Toxicity (Overdose): Not Available
Protein Binding: 30%
Biotransformation: Not Available
Half Life: 2.5 hours
Dosage Forms of Tizanidine Hcl: Tablet Oral
Chemical IUPAC Name: 6-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-2,1,3-benzothiadiazol-7-amine
Chemical Formula: C9H8ClN5S
Tizanidine on Wikipedia: https://en.wikipedia.org/wiki/Tizanidine
Organisms Affected: Humans and other mammals
