Description
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 this medicine, you must have blood tests regularly to see if the medicine is affecting your liver.
This medicine was available only with your doctor's prescription. Tacrine (Cognex®) was withdrawn from the US market in May 2012.
Before Using
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 this medicine, the following should be considered:
Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine 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.
Pediatric
Studies on this medicine 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.
Geriatric
Studies on tacrine have been done only in middle-aged and older patients. Information on the effects of tacrine is based on these patients.
Breastfeeding
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.
Drug Interactions
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Viloxazine
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Amifampridine
- Bupropion
- Capmatinib
- Carbamazepine
- Diazoxide
- Donepezil
- Givosiran
- Hydroxychloroquine
- Pixantrone
- Ritlecitinib
Using this medicine 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
- Levonorgestrel
- Theophylline
Other Interactions
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. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
- Tobacco
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. 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
Take this medicine 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 this medicine 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.
Dosing
The dose of this medicine 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 this medicine. 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 this medicine and your liver tests are normal. However, the dose is usually not more than 40 mg four times a day.
- For treatment of Alzheimer's disease:
Missed Dose
If you miss a dose of this medicine, 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.
Storage
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
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 this medicine 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 this medicine. 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 this medicine before you do anything that could be dangerous if you are dizzy, clumsy, or unsteady.
Do not stop taking this medicine or decrease your dose without first checking with your doctor. Stopping this medicine 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.
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 this medicine 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
Rare
- 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)
This medicine 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.
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