This psychoactive medicine contains tacrine as active ingredient. It belongs to the group of cholinesterase inhibitors. These drugs work by increasing  the function of certain receptors in the brain that are stimulated by the neurotransmitter acetylcholine. They do this by interfering with cholinesterase, the enzyme that breaks down acetylcholine. Most people with dementia (including Alzheimer’s disease) develop a shortage of this brain chemical early in the disease.

Prescribed for

The drug is prescribed for:

  • Dementia
  • Alzheimer’s disease
  • Lewy body dementia
  • Vascular dementia
  • Dementia associated with Parkinson’s disease
  • Poststroke aphasia
  • Improvement of memory in multiple sclerosis

There is no evidence that cholinesterase inhibitors reverse the degenerative effects of dementia, but they may slow the rate at which the disease worsens.

Before using this medicine

Before you use this medicine check with your doctor, or  pharmacist:

  • if you ever had any unusual or allergic reaction to any psychoactive medicine;
  • if you have a heart disease;
  • if you have a gastric ulcer of stomach bleeding;
  • if you have liver problems;
  • if you have kidney insufficiency.


Take this medicine only as directed by your doctor, to benefit your condition as much as possible. Do not take more of it, do not take it more often, and do not take it for a longer period of time than your doctor ordered.

Dosage:The information below is based on the dosage guidelines your doctor uses. Depending on your condition and medical history, your doctor may prescribe a different regimen.

The usual starting dose is 40-100 mg a day, divided into 4 doses, at least 4 to 6 weeks. Do not increase the dose during this period unless  directed.

The doctor may then increase the dose if response to the drug warrants  it.

Side Effects

Along with the needed effects, a medicine may cause some unwanted effects.

  • Common side effects include:
    • Headache
    • General pain
    • Accidents
    • Nausea
    • Diarrhea
    • Sleeplessness
    • Dizziness
    • Tiredness
    • Vomiting
    • Appetite loss
    • Muscle cramps
  • Less common and rare side effects include:
    • Arthritis
    • Depression
    • Abnormal dreams
    • Fainting
    • Black-and-blue marks
    • Weight loss
  • Contact your doctor if you experience any side effects not listed above.

Warnings and Cautions

  • People with heart disease should use this medicine with caution because it may slow heart rate and cause fainting.
  • The medicine may be expected to cause increased stomach acid and increased activity of the gastrointestinal tract. Possible complications include ulcers and bleeding. Alcohol may worsen this effect.
  • Using this medicine may also lead to urinary blockage, increase the risk of generalized seizures, and worsen asthma or other pulmonary Use with caution if you have these conditions.
  • People with severe liver disease should not take this medicine.

Driving or Hazardous Work

Do not drive until you learn how the medicine affects you. Do not work around dangerous machinery. Do not climb ladders or work in high places. Danger increases if you drink alcohol or take medicines affecting alertness and reflexes.


This medicine can be expected to increase the effects of:

  • Cevimeline
  • Surgical anesthetic drugs
  • Drugs that irritate the stomach and intestines
  • Aspirin
  • Ibuprofen

The breakdown of this medicine in the liver can be slowed by:

  • Ketoconazole
  • Itraconazole
  • Quinidine
  • Ritonavir
  • Cimetidine
  • Ciprofloxacin
  • Diltiazem
  • Erythromycin
  • Fluconazole
  • Clomipramine
  • Fluoxetine
  • Haloperidol
  • Paroxetine
  • Ranitidine
  • Be sure to tell your doctor about any medications you are currently taking.


An overdose of this medicine can be very serious. Symptoms include:

  • Severe nausea
  • Vomiting
  • Salivation
  • Sweating
  • Slow heart rate
  • Low blood pressure
  • Slow breathing rate
  • Convulsions
  • Muscle weakness
  • Collapse

Take the overdose victim to a hospital emergency room at once. Always bring the prescription bottle or  container.


Tablets, capsules, etc. should be stored at room temperature in tightly closed, light-resistant containers as directed by your pharmacist. Keep out of reach of children since overdose is especially dangerous in young children. Do not store in the bathroom medicine cabinet because the heat or moisture may cause the medicine to break down. Keep the liquid form of the medicine from freezing.

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