Tacrine (Oral)

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 happen 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 Tacrine (Cognex®) was withdrawn from the US market in May 2012.

It is important for your doctor to check your progress at regular visits. You must have your blood tested every other week for at least the first 4 to 16 weeks after starting 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 your doctor may decide to test 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, inform the medical doctor or dentist in charge that you are taking this medicine. Taking tacrine with medicines that are sometimes used during surgery or dental or emergency treatments may increase the effects of those medicines.

Tacrine may cause some people to feel dizzy, clumsy, or unsteady. Make sure you know how this medicine affects you before doing anything that could be dangerous if you are dizzy, clumsy, or unsteady.

Do not stop taking this medicine or lower your dose without first checking with your doctor. Stopping this medicine suddenly or significantly reducing the dose may lead to changes in mental state or behavior.

If you think you or someone else may have taken an overdose of tacrine, seek emergency help immediately. An overdose of tacrine may result in seizures or shock. Some signs of shock include large pupils, irregular breathing, and a fast weak pulse. Other signs of an overdose are severe nausea and vomiting, increased muscle weakness, excessive sweating, and excessive drooling.

In deciding to use a medicine, you and your doctor need to consider the risks of taking the medicine versus the benefits it may provide. For this medicine, keep the following points in mind:

Allergies

Inform your doctor if you have ever had any unusual or allergic reactions to this medicine or any other medicines. Also, let your healthcare professional know if you have any other allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, carefully read the label or package ingredients.

Pediatric

Research on this medicine has only been conducted in adult patients, and there is no specific information comparing the use of tacrine in children to its use in other age groups.

Geriatric

Research on tacrine has only been conducted in middle-aged and older patients. Information about the effects of tacrine is based on these patients.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication during breastfeeding. Consider the potential benefits and risks before taking this medication while breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while in other cases, two different medicines may be used together even if an interaction could occur. In these situations, your doctor may need to adjust the dose or take other precautions. It's crucial that your healthcare professional knows if you are taking any of the medicines listed below. The following interactions are highlighted based on their potential significance and are not necessarily a complete list.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or adjust some of the other medicines you take.

• Viloxazine

Using this medicine with any of the following medicines is usually not recommended, but may be necessary 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
• Donepezil
• Givosiran
• Pacritinib
• Pixantrone
• Ritlecitinib
• Tocilizumab

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both medications may be the best option for you. If both medicines are prescribed together, your doctor may adjust the dose or how often you use one or both of the medicines.

• Estradiol
• Fluvoxamine
• Haloperidol
• Levonorgestrel
• Theophylline

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around the time of eating food or certain types of food due to potential interactions. Using alcohol or tobacco with some medicines may also lead to interactions. The following interactions are highlighted based on their potential significance and are not necessarily a complete list.

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 adjust the dose or how often you use this medicine, or provide special instructions regarding the use of food, alcohol, or tobacco.

• Tobacco

Other Medical Problems

Having other medical problems may affect the use of this medicine. Make sure to inform your doctor if you have any other medical issues, especially:

• Asthma (or a history of) or
• Heart problems, including slow heartbeat or low blood pressure (hypotension), or
• Intestinal blockage or
• Liver disease (or a history of) or
• Parkinson's disease or
• Stomach ulcer (or a history of) or
• Urinary tract blockage or difficulty urinating—Tacrine may worsen these conditions

• Other brain diseases, or
• Epilepsy or a history of seizures or
• Head injury with loss of consciousness—Tacrine may cause seizures

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 check for others by doing certain tests.

Tacrine may cause some serious side effects, including liver problems. You and your doctor should talk about the benefits of this medicine as well as the risks of taking 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 happen 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.

Pharmacologic Class: Cholinesterase Inhibitor, Centrally Acting

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.

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.