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Drugs reference index «tacrine»

tacrine (Oral route)


Commonly used brand name(s):

In the U.S.

  • Cognex

Available Dosage Forms:

  • Capsule

Therapeutic Class: Central Nervous System Agent

Pharmacologic Class: Cholinesterase Inhibitor, Centrally Acting

Uses For tacrine

Tacrine is used to treat the symptoms of mild to moderate Alzheimer's disease. Tacrine will not cure Alzheimer's disease, and it will not stop the disease from getting worse. However, tacrine can improve thinking ability in some patients with Alzheimer's disease.

In Alzheimer's disease, many chemical changes take place in the brain. One of the earliest and biggest changes is that there is less of a chemical messenger called acetylcholine (ACh). ACh helps the brain to work properly. Tacrine slows the breakdown of ACh, so it can build up and have a greater effect. However, as Alzheimer's disease gets worse, there will be less and less ACh, so tacrine may not work as well.

Tacrine may cause liver problems. While taking tacrine, you must have blood tests regularly to see if the medicine is affecting your liver.

tacrine is available only with your doctor's prescription.

Before Using tacrine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For tacrine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to tacrine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Studies on tacrine have been done only in adult patients, and there is no specific information comparing use of tacrine in children with use in other age groups.


Studies on tacrine have been done only in middle-aged and older patients. Information on the effects of tacrine is based on these patients.


Pregnancy CategoryExplanation
All TrimestersCAnimal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Using tacrine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Estradiol
  • Fluvoxamine
  • Haloperidol
  • Ibuprofen
  • Levonorgestrel
  • Riluzole
  • Theophylline

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of tacrine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Asthma (or history of) or
  • Heart problems, including slow heartbeat or hypotension (low blood pressure), or
  • Intestinal blockage or
  • Liver disease (or history of) or
  • Parkinson's disease or
  • Stomach ulcer (or history of) or
  • Urinary tract blockage or difficult urination—Tacrine may make these conditions worse
  • Brain disease, other, or
  • Epilepsy or history of seizures or
  • Head injury with loss of consciousness—Tacrine may cause seizures

Proper Use of tacrine

Take tacrine only as directed by your doctor. Do not take more or less of it, and do not take it more or less often than your doctor ordered. Taking too much may increase the chance of side effects, while taking too little may not improve your condition.

Tacrine is best taken on an empty stomach (1 hour before or 2 hours after meals). However, if tacrine upsets your stomach, your doctor may want you to take it with food.

Tacrine seems to work best when it is taken at regularly spaced times, usually four times a day.


The dose of tacrine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of tacrine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For treatment of Alzheimer's disease:
      • Adults—To start, 10 milligrams (mg) four times a day. Your doctor may increase your dose gradually if you are doing well on tacrine and your liver tests are normal. However, the dose is usually not more than 40 mg four times a day.

Missed Dose

If you miss a dose of tacrine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Precautions While Using tacrine

It is important that your doctor check your progress at regular visits. Also, you must have your blood tested every other week for at least the first 4 to 16 weeks when you start using tacrine to see if tacrine is affecting your liver. If all of the blood tests are normal, you will still need regular testing, but then your doctor may decide to do the tests less often.

Tell your doctor if your symptoms get worse, or if you notice any new symptoms.

Before you have any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are taking tacrine. Taking tacrine together with medicines that are sometimes used during surgery or dental or emergency treatments may increase the effects of these medicines.

Tacrine may cause some people to become dizzy, clumsy, or unsteady. Make sure you know how you react to tacrine before you do anything that could be dangerous if you are dizzy, clumsy, or unsteady.

Do not stop taking tacrine or decrease your dose without first checking with your doctor. Stopping tacrine suddenly or decreasing the dose by a large amount may cause mental or behavior changes.

If you think you or someone else may have taken an overdose of tacrine, get emergency help at once. Taking an overdose of tacrine may lead to seizures or shock. Some signs of shock are large pupils, irregular breathing, and fast weak pulse. Other signs of an overdose are severe nausea and vomiting, increasing muscle weakness, greatly increased sweating, and greatly increased watering of the mouth.

tacrine Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Some side effects will have signs or symptoms that you can see or feel. Your doctor may watch for others by doing certain tests

Tacrine may cause some serious side effects, including liver problems. You and your doctor should discuss the good tacrine will do as well as the risks of receiving it.

Check with your doctor as soon as possible if any of the following side effects occur:

More common
  • Clumsiness or unsteadiness
  • diarrhea
  • loss of appetite
  • nausea
  • vomiting
Less common
  • Fainting
  • fast or pounding heartbeat
  • fever
  • high or low blood pressure
  • skin rash
  • slow heartbeat
  • Aggression, irritability, or nervousness
  • change in stool color
  • convulsions (seizures)
  • cough, tightness in chest, troubled breathing, or wheezing
  • stiffness of arms or legs, slow movement, or trembling and shaking of hands and fingers
  • trouble in urinating
  • yellow eyes or skin
Symptoms of overdose
  • Convulsions (seizures)
  • greatly increased sweating
  • greatly increased watering of mouth
  • increasing muscle weakness
  • low blood pressure
  • nausea (severe)
  • shock (fast weak pulse, irregular breathing, large pupils)
  • slow heartbeat
  • vomiting (severe)

tacrine may also cause the following side effect that your doctor will watch for:

More common
  • Liver problems

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Abdominal or stomach pain or cramping
  • dizziness
  • headache
  • indigestion
  • muscle aches or pain
Less common
  • Belching
  • fast breathing
  • flushing of skin
  • general feeling of discomfort or illness
  • increased sweating
  • increased urination
  • increased watering of eyes
  • increased watering of mouth
  • runny nose
  • swelling of feet or lower legs
  • trouble in sleeping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

The information contained in the Thomson Healthcare (Micromedex) products as delivered by Drugs.com is intended as an educational aid only. It is not intended as medical advice for individual conditions or treatment. It is not a substitute for a medical exam, nor does it replace the need for services provided by medical professionals. Talk to your doctor, nurse or pharmacist before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Only your doctor, nurse, or pharmacist can provide you with advice on what is safe and effective for you.

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  • tacrine Concise Consumer Information (Cerner Multum)
  • Tacrine MedFacts Consumer Leaflet (Wolters Kluwer)
  • Cognex Prescribing Information (FDA)
  • Cognex Detailed Consumer Information (PDR)

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