Tizanidine
Class:Muscle relaxants
Mechanism of action
Agonist at adrenergic
sites;presumably reduces spasticity by increasing presynaptic inhibition of
motor neurons.
Pharmacokinetics
Oral:peak 1.5 hr
bioavailability 40 percent due to extensive 1st- pass metabolism ;30
percent bound to plasma proteins;metabolized by liver to inactive metabolites,excreted
in urine and feces.
Indications
Painful muscle spasm
associated with static and functional disorders of the spine (cervical and
lumbar syndrome) or following surgery,e.g for herniated intervertebral disc or
osteoarthritis of the hip.spasticity due to neurological disorders such as
multiple sclerosis,chronic myelopathy,degenerative spinal cord
diseases,cerebrovascular accidents and cerebral palsy.
Contraindications
Known
hypersensitivity to tizanidine or any component;significantly impaired hepatic
function.
Precautions
Liver function tests inpatients
receiving doses of 12 mg or above in patients with impaired kidney function;if
patients drive a vehicle or use machines,in pregnancy and lactation;in children
and elderly.
Side effects
With low doses,such
as those recommended for the relief of painful muscle
spasms:somnolence,drowsiness,fatigue,dizziness,dry
mouth,nausea,gastrointestinal disturbances and slight reduction in blood
pressure.With the higher doses,as recommended for for the treatment of
spasticity,muscle weakness and insomnia,sleep
disorders,hallucination,hypotention,bradycardia,isolated cases of acute
hepatitis.
Pregnancy
Pregnancy category C
Drug interaction
Antihypertensives
including diuretics;alcohol,sedatives.
Dosage
Painful muscle
spasm:2-4 mg t.i.d.in tablet form.Spasticity due to neurological
disorders:tablet:maximum initial dose 6 mg/day in 3 divided doses.then increase
stepwise to 12-36 mg/day.
Brands
Tabs.Movax 2
mg,Tabs.Ternelin 2 mg.
