Generic Name

Tizanidine

Precaution

Hepatic or renal insufficiency. Children, elderly, pregnancy and lactation. Monitor LFT regularly. Stop treatment if liver enzymes are raised persistently >3 times upper limit of normal range. Avoid abrupt withdrawal of therapy. Lactation: May be excreted in breast milk due to lipophilic nature; use caution

Indication

Spasticity, Painful muscle spasm

Contra Indication

Severe hepatic dysfunction.

Dose

N/A

Side Effect

>10% Dry mouth (46-50%),Somnolence (46-50%),Dizziness (16-20%),Asthenia (10-45%) 1-10% Blurred vision (3%),Constipation (4%),Infection (6%),LFT abnormalities (3-5%),Speech disorder (3%),Vomiting (3%),Urinary frequency (3%),UTI (10%) Frequency Not Defined Asthenia,Bradycardia,Hypotension,Orthostatic hypotension,Syncope (rare) Potentially Fatal: Hepatitis.

Pregnancy Category

Mode of Action

Tizanidine, an alpha2-adrenergic agonist, is a centrally acting muscle relaxant structurally related to clonidine. It reduces spasticity by increasing presynaptic inhibition of motor neurons and has no direct effect on skeletal muscle, the neuromuscular junction or on monosynaptic spinal reflexes.

Interaction

Potentiates hypotensive effect of antihypertensives. Increased CNS effects with alcohol and CNS depressants. Increased bradycardia with ?-blockers and digoxin. Increased serum concentration of tizanidine with CYP1A2 inhibitors e.g. zileuton, ciprofloxacin and other fluoroquinolones, antiarrhythmics, cimetidine, famotidine, oral contraceptives, aciclovir and ticlopidine. Decreased serum concentrations of tizanidine with rifampicin. Use with caution with drugs that may prolong QT interval.

Pregnancy Category Note

Pregnancy category: C Lactation: May be excreted in breast milk due to lipophilic nature; use caution

Adult Dose

Oral Muscle Spasticity Spasticity associated with multiple sclerosis and spinal cord injury Initial: 2 mg q6-8hr; no more than 3 doses q24hr Maintenance: Increase by 2 to 4 mg until satisfactory response is achieved with minimum 1-4 days between dose increments Not to exceed 36 mg/day Painful muscle spasm associated with musculoskeletal conditions Adult: 2-4 mg tid. Elderly: Not recommended. Hepatic impairment: Avoid or use with extreme caution.

Child Dose

Child < 18 years: Not recommended

Renal Dose

Renal impairment: CrCl (ml/min) Dosage Recommendation <25 Initially, 2 mg once daily, gradually increasing the dose before increasing the frequency of admin.

Administration

N/A