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Tetrabenazine

Formula Drugs

Where it is used and how it works?

Tetrabenazine is used to help control Huntington’s disease, senile chorea, and hemiballismus. This also helps to control a movement disorder called tardive dyskinesia. 

This medicine works by reducing the rations of definite neurotransmitters within the nerve cells in the brain. These neurotransmitters include dopamine, noradrenaline, and serotonin. They are involved in passing messages between nerve cells in the brain and the normal functioning of the brain and nervous system. Reducing the brain cells of these neurotransmitters helps to stop the nerve cells from sending unsuitable messages to the muscles. It can help control jerky, irregular and uncontrollable movements that are the result of certain diseases of the brain and nervous system. 

Huntington’s disease 

This is a rare inherited condition that causes the advanced breakdown of nerve cells in the brain. Huntington’s disease has a broad impact on a person’s functional abilities and usually results in movement, thinking, and psychiatric disorders. This disease’s symptoms can develop at any time, but they frequently first appear when people are in their 30s or 40s. If the condition develops before age 20, it’s called juvenile Huntington’s disease. When Huntington develops early, symptoms are somewhat different and the disease may progress faster. Huntington’s disease usually causes movement, cognitive, and psychiatric disorders with a wide spectrum of signs and symptoms. Some symptoms appear more dominant or have a greater effect on functional ability, but that can change throughout the disease. This condition is caused by an inherited defect in a single gene. Huntington’s disease is an autosomal dominant disorder, which means that a person needs only one copy of the defective gene to develop the disorder. Except for genes on the sex chromosomes, a person inherits two copies of every gene. A parent with a defective gene could pass along the defective copy of the gene or the healthy copy. Each child in the family, therefore, has a 50% chance of inheriting the gene that causes the genetic disorder.

Senile chorea

This is a relatively mild and uncommon disorder that occurs in elderly adults and is characterized by choreic movements. Chorea refers to rapid complex body movements that look well-coordinated and purposeful but are, in fact, involuntary. 

Hemiballismus

This is the most common degenerative disorder causing chorea. In Huntington disease, drugs that suppress dopaminergic activity and dopamine-depleting drugs can be used to treat chorea. Antipsychotics may also help by lessening the neuropsychiatric symptoms commonly associated with Huntington disease. However, improvement may be limited and transient. All of these drugs may be judiciously used to treat choreas without a definable cause.

Tardive dyskinesia

This is a side effect caused by neuroleptic drugs. This condition causes uncontrolled or involuntary movements. They are often prescribed for psychiatric disorders and neurological disorders. Sometimes neuroleptic drugs are prescribed for gastrointestinal disorders. These drugs block dopamine receptors in the brain. Dopamine is a chemical that helps control emotions and the pleasure center of your brain. It also plays a role in your motor functions. Too little dopamine may interfere with your muscles and cause the signs and symptoms of Tardive dyskinesia. Mild to moderate cases of Tardive dyskinesia cause stiff, jerking movements of the:

  • Jaw
  • Face
  • Lips
  • Tongue

These movements may include blinking frequently and sticking the tongue out. People with moderate cases of this condition often experience additional uncontrolled movement in the:

  • Arms
  • Toes
  • Fingers
  • Legs

The Recommended Dosage

The starting dose should be 12.5 mg per day given once in the morning. After one week, the dose should be increased to 25 mg per day given as 12.5 mg twice a day. This drug should be titrated up slowly at weekly intervals by 12.5 mg daily, to allow the identification of a tolerated dose that reduces chorea. If a dose of 37.5 to 50 mg per day is needed, it should be given in a three times a day regimen. The maximum recommended single dose is 25 mg. 

Tetrabenazine should be swallowed with a full glass of water. They can be taken either with or without a meal. The dose of this medicine that is prescribed and how often it needs to be taken depends on the condition being treated. It is important to follow the instructions given by your doctor. If you forget to take a dose take it as soon as you remember unless it is nearly time for your next dose. In this case, just leave out the forgotten dose and take your next dose as usual. Don’t take a double dose to make up for a missed dose. You should not suddenly stop taking this medicine unless your doctor tells you to. If treatment with this medicine is stopped, this should usually be done gradually.

Its Side Effects

  • Insomnia
  • Drowsiness
  • Tired feeling
  • Nausea
  • Breast swelling or discharge
  • Sleep problems or insomnia
  • Feeling anxious or irritable
  • Cold symptoms

Tell your doctor if you have serious side effects of Xenazine including:

  • Extreme drowsiness
  • Mood or behavior changes
  • Restlessness
  • Agitation 
  • Trouble swallowing
  • Problems with balance
  • Dizziness
  • Fast or pounding heartbeat
  • Fainting 
  • Very stiff muscles, high fever, sweating, 
  • Muscle pain or tenderness with fever or flu symptoms 
  • Urinating less than usual or not at all, weight gain, swelling, or shortness of breath.

Warnings and Precautions

  • Do not drink alcohol while you are taking this medicine. This is likely to make you feel drowsy or dizzy that you may experience worse.
  • Certain medicines should not be used during breastfeeding or pregnancy. However, other medicines may be safely used in breastfeeding or pregnancy providing the benefits to the mother outweighs the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine. 
  • Tetrabenazine should be given carefully in people with a history of depression, decreased liver or kidney function, and a history of abnormal heart rhythms. 
  • This drug is not recommended for use in people with depression, Parkinson’s disease, or people taking a MOAI antidepressant in the last two weeks. 
  • Never share this or any of your medicines with others even if they have the same symptoms as yours.