Tizanidine Hydrochloride Tablets

Pharmacological action: Tizanidine is a central α2 adrenergic receptor agonist, which may reduce tonic spasm by enhancing the presynaptic inhibition of motor neurons. Animal experiments show that tizanidine has no direct effect on skeletal fibers and neuromuscular junctions, and has a weak effect on monosynaptic spinal reflexes. Tizanidine has the strongest effect on multisynaptic pathways, and these effects are believed to be related to the reduced facilitation of spinal motor neurons. Toxicological studies: Genetic toxicity: The results of the tizanidine Ames test, mammalian gene mutation test, Chinese hamster cell chromosome aberration test, mouse bone marrow micronucleus test, Chinese hamster bone marrow micronucleus test and cytogenetic test, mouse dominant lethal mutagenesis test and mouse unscheduled DNA synthesis test were all negative. Reproductive toxicity: Male rats were given tizanidine 10mg/kg and female rats 3mg/kg (calculated in mg/m2, equivalent to 2.7 times and 1 times the maximum recommended dose for humans, respectively), and no effect on fertility was observed. When male rats were given 30 mg/kg of tizanidine and female rats were given 10 mg/kg, fertility decreased and the mothers showed symptoms of sedation, weight loss and movement disorders. Rats were given 3 mg/kg of tizanidine and rabbits were given 30 mg/kg (calculated in mg/m2, equivalent to 1 and 16 times the maximum recommended dose for humans, respectively), and no teratogenic effects were observed. Administration of 1 to 8 times the maximum recommended dose of tizanidine can prolong the gestation period of rats, leading to increased perinatal pup loss and developmental delay. When rabbits were given tizanidine at 1 mg/kg and higher doses, post-implantation embryo loss increased. Carcinogenicity: Mice were given tizanidine orally at a dose of 16 mg/kg for 78 consecutive weeks, and rats were given tizanidine orally at a dose of 9 mg/kg for 104 consecutive weeks (calculated in mg/m2, equivalent to 2 and 2.5 times the maximum recommended dose for humans, respectively), and no significant increase in tumor incidence was observed.

The main ingredient of this product is tizanidine hydrochloride, and its chemical name is 5-chloro-4-[(2-imidazolin-2-yl)amino]-2,1,3-benzothiadiazole hydrochloride.

This product is white to off-white tablets.

Tizanidine hydrochloride tablets are central skeletal muscle relaxants used for: (1) Improvement of painful muscle spasms caused by the following diseases: local pain syndromes such as neck, shoulder and waist pain. (2) Central myotonia caused by the following diseases: cerebrovascular accidents, postoperative sequelae (spinal cord injury, brain injury), spinocerebellar degeneration, multiple sclerosis, amyotrophic lateral sclerosis, etc.

When used for painful muscle spasms: Oral, 2 mg once, 1 to 3 times a day. The dosage should be increased or decreased according to the patient's age and symptoms. Usually the initial dose is 2 mg a day, and the dose can be gradually increased and taken in divided doses. The initial dose is usually taken before bedtime. When used for central myotonia: The dose should be adjusted according to the patient's needs. The initial dose should not exceed 6 mg a day (taken in 3 times), and can be gradually increased by 2 to 4 mg every half a week or a week. Usually a dose of 12 to 24 mg a day (taken in 3 to 4 times) can achieve good therapeutic effects, and the total amount per day should not exceed 36 mg.

When low doses are used to treat painful muscle spasms, adverse reactions are rare, usually mild and short-lived, including drowsiness, fatigue, dizziness, dry mouth, nausea, gastrointestinal dysfunction, and mild decrease in blood pressure. When high doses are used to treat central myotonia, the above adverse reactions are more common and obvious.

1. Patients who are allergic to tizanidine hydrochloride and other components are prohibited from using it. 2. It is forbidden to use tizanidine simultaneously with fluvoxamine or ciprofloxacin (CYP1A2 inhibitors). Clinical studies have shown that when tizanidine is used simultaneously with fluvoxamine or ciprofloxacin, the pharmacokinetic parameters (area under the curve AUC, elimination half-life t1/2, maximum blood drug concentration Cmax, oral bioavailability) are increased, while the plasma clearance rate is reduced. This pharmacokinetic interaction may lead to serious adverse events. 3. Patients with severe liver damage are prohibited from using it.

Precautions for children: The safety and effectiveness of this product in pediatric patients has not been established. Precautions for pregnancy and lactation: This product has not been fully studied in pregnant and lactating women, and it is unknown whether it is secreted through breast milk. However, due to the fat solubility of this product, it may enter breast milk. Therefore, the use of this product in pregnant and lactating women should be considered only after the benefits outweigh the risks after fully weighing the pros and cons. Precautions for the elderly: This product is mainly excreted in the kidneys. For elderly patients, because it is often accompanied by low renal function, it can lead to a continuous increase in blood drug concentration, so the dosage should be reduced. This product has the effect of lowering blood pressure, and elderly patients should use it with caution. It is recommended to monitor renal function in elderly patients.

This product is mainly metabolized by the liver metabolic enzyme cytochrome P450 (CYP) 1A2, so attention should be paid to whether there are drugs that affect the activity of this enzyme at the same time. Especially when used simultaneously with drugs that inhibit CYP1A2, the blood concentration of this product may increase. In addition, when used simultaneously with drugs that activate CYP1A2, the blood concentration of this product may decrease. 1. Fluvoxamine and ciprofloxacin It is forbidden to use tizanidine in combination with fluvoxamine or ciprofloxacin. The use of tizanidine with fluvoxamine or ciprofloxacin will cause changes in pharmacokinetics, resulting in a significant decrease in blood pressure, increased drowsiness and psychomotor impairment. 2. Due to potential drug interactions, tizanidine should be avoided in combination with other CYP1A2 inhibitors, such as zileuton, quinolones except ciprofloxacin (prohibited), antiarrhythmic drugs (amiodarone, mexiletine, propafenone), cimetidine, famotidine, oral contraceptives, acyclovir and ticlopidine. If it is necessary to use it clinically, the initial treatment dose should be 2 mg, and then the dose should be gradually increased according to the patient's response to treatment. If adverse reactions such as hypotension, bradycardia or excessive drowsiness occur, please reduce or stop tizanidine treatment. 3. Oral contraceptives have not been specifically studied for pharmacokinetic interactions between oral contraceptives and tizanidine. However, a retrospective analysis of population pharmacokinetic data after single and multiple doses of tizanidine showed that the clearance of tizanidine in women taking oral contraceptives at the same time was 50% lower than that in women not taking oral contraceptives. 4. Alcohol Alcohol increases the AUC of tizanidine by about 20%, and its Cmax also increases by about 15%. This is related to the increase in adverse reactions of tizanidine. The central nervous system depressant effects of tizanidine and alcohol are additive. 5. Other central nervous system depressants Tizanidine and central nervous system depressants (such as benzodiazepines, opioids, tricyclic antidepressants) have additive sedative effects. Patients who take tizanidine with other central nervous system depressants should be monitored for symptoms of excessive sedation. 6. ɑ2 adrenergic receptor agonists are not recommended for use with other ɑ2 adrenergic receptor agonists because the hypotensive effect may be cumulative.

Keep sealed.

1 mg x 24 tablets, 1 mg x 36 tablets, 1 mg x 48 tablets, 1 mg x 60 tablets

24 months

Sichuan Credit Pharmaceutical Co., Ltd.

• Founded in:

  2000-04-20

• Address:

  Pharmaceutical Industrial Park, Luzhou National High-tech Zone, Sichuan Province

• Tax NO.:

  915105217144041624

• Registered Funds:

  27.214286 million yuan

• Website:

  Log in to view

• Email:

  Log in to view