Zanaflex (Tizanidine)

Not only gymnasts and athletes who may suffer muscles pain and back pain. Lifting weights, especially heavy weights, improperly may cause serious back pain. Excessive exertion with insufficient rest, will cause general fatigue and muscles pain. Eventually, such habits will lead to muscles ache, back pain and perhaps, other back bone problems. Rest is important and keeping up healthy habits is important too. But, what if rest is not enough for temporary muscles ache and back pain. Then, perhaps a muscle relaxant like Zanaflex, chlorzoxazone, or baclofen, is needed in addition to resting.

NSAIDs are very effective analgesics for muscles pain and back pain, however, they have undesirable effects on stomach. Many of the NSAIDs can cause stomach irritation and in severe cases, stomach ulcers! Non steroidal anti-inflammatory drugs can help, but the stomach problems are inevitable upon their usage for so long.


Back to muscle relaxants…Zanaflex is a centrally acting muscle relaxant affecting the spinal cord principally. It’s able to diminish the muscle tone and has a moderate central analgesic activity. Its strong muscle relaxation ability is accounted to both of the previous effects. The rapid and almost complete absorption is another great advantage, making Zanaflex one of the best muscle relaxants.

Muscles Pain

Zanaflex Indications

  • For treatment of painful muscle spasms and chronic muscles pain like neck pain and back pain.
  • For treatment of muscle spasms of spinal and cerebral origins.

Zanaflex Doses

  • The usual dose is 2-4 mg 3 times daily and not more than 2 mg each time, which is a total daily dose of 6 mg. The 2 mg dose could be increased according to the patient’s need.
  • Renal impairment patients should take a dose of 2 mg once daily only and monitoring may be required.

Overdose of Zanaflex can be eliminated by taking activated char coal repeatedly. Sometimes, forced diuresis is required to accelerate the elimination process.


  • It is not recommended for patients less than 18 years old.
  • It is not preferable for geriatrics, elder than 65 years old.
  • Patients with moderate hepatic impairment must use it with caution and it’s better not to use it at all.


  1. Hypersensitivity to Zanaflex.
  2. Severe impairment of the hepatic (liver) function because Zanaflex is majorly metabolized in liver.
  3. Severe impairment of renal (kidney) function as Zanaflex is eliminated through the kidneys.
  4. Pregnancy and breast feeding.

Side Effects

Transient side effects due to low doses:

  • Fatigue
  • Dizziness
  • Nausea
  • Dry mouth

Side effects of high doses are the same as those of low doses, but are more intense and frequent. In addition to other effects like insomnia, muscular weakness, blurred vision and hypotension. Zanaflex administration should be stopped gradually and not suddenly. A withdrawal syndrome occurs in case of sudden withdrawal of Zanaflex. It includes rebound hypertension and tachycardia.



1. Medications which affect the metabolism of Zanaflex

Taking such medications concomitantly with Zanaflex will make it last for a longer time in plasma (make its elimination slow). This leads to effects similar to those of Zanaflex overdose that are of course undesirable. Such effects include dizziness and prolonged hypotension. Some of these medications are:

  • Ciprofloxacin antibiotic
  • Fluoroquinolones such as norfloxacin
  • Fluvoxamine
  • Antiarrhythmics like amiodarone, mexiletine and propafenone
  • Cimetidine (antihistaminic)
  • Rofecoxcib (NSAID)
  • Oral contraceptives

2. Antihypertensive medications

Taking Zanaflex with antihypertensives, including diuretics, will potentiate their effects critically. The overall effects are excessive hypotension and bradycardia (decreased heart rate).

3. Rifampicin antibiotic

Concomitant administration of rifampicin with Zanaflex, decreases the concentration of the later by 50%. This results in lowering the therapeutic effects of Zanaflex. Long term co-administration should be avoided unless careful adjustment of doses is guaranteed.

3. Smoking cigarettes

Smokers who take Zanaflex have a lessened therapeutic effect by around 30% than people who do not smoke. Smokers require higher doses of Zanaflex than other people to achieve the same therapeutic effects.

4. Alcohol

Drinking alcohol and taking Zanaflex at the same time, may increase side effects like sedation and hypotension. So, while taking Zanaflex, drinking alcohol should be totally ceased. Zanaflex can increase the depressing effects of alcohol on central nervous system.