What is Tacrine: Uses, Dosage, Side Effects and More

Tacrine is a medication that was once used to treat Alzheimer's disease, but it's no longer available in most countries due to serious liver problems. This drug was designed to help improve memory and thinking skills in people with dementia by blocking an enzyme that breaks down acetylcholine, a brain chemical important for memory.

While tacrine made history as the first FDA-approved treatment for Alzheimer's disease in 1993, doctors discovered it could cause severe liver damage. Most countries have since withdrawn it from the market, and safer alternatives are now available for treating dementia symptoms.

What is Tacrine?

Tacrine belongs to a class of drugs called cholinesterase inhibitors. It works by preventing the breakdown of acetylcholine, a neurotransmitter that helps nerve cells communicate with each other in the brain.

This medication was originally developed to help slow down the progression of memory loss and confusion in Alzheimer's patients. However, its use became limited due to significant safety concerns, particularly the risk of liver toxicity that could be life-threatening.

What is Tacrine Used For?

Tacrine was primarily prescribed for mild to moderate Alzheimer's disease. Doctors used it to help patients maintain their cognitive abilities for a longer period and potentially slow the decline in daily functioning.

The medication was also sometimes considered for other types of dementia, though this was less common. It's important to note that tacrine doesn't cure Alzheimer's disease or stop its progression completely - it only provided temporary symptom relief for some patients.

How Does Tacrine Work?

Tacrine works by blocking an enzyme called acetylcholinesterase in your brain. This enzyme normally breaks down acetylcholine, a chemical messenger that's crucial for memory and learning.

By preventing this breakdown, tacrine helps maintain higher levels of acetylcholine in the brain. This can temporarily improve communication between nerve cells, which may help with memory, attention, and reasoning skills. However, tacrine is considered a relatively weak medication compared to newer dementia treatments, and its effects are modest at best.

How Should I Take Tacrine?

If tacrine were still available, it would typically be taken by mouth four times daily, usually between meals. Taking it on an empty stomach helps your body absorb the medication better.

The medication would need to be started at a low dose and gradually increased over several weeks. This slow increase helps reduce side effects, particularly nausea and vomiting. Regular blood tests would be essential to monitor liver function, as liver damage can occur without obvious symptoms.

How Long Should I Take Tacrine For?

The duration of tacrine treatment would depend on how well you respond to the medication and whether you develop side effects. Some patients might see benefits within a few weeks, while others might need several months to notice improvements.

Treatment would typically continue as long as the benefits outweigh the risks. However, regular monitoring for liver problems would be crucial, and the medication would need to be stopped immediately if liver enzyme levels become elevated.

What Are the Side Effects of Tacrine?

Tacrine can cause several side effects, ranging from mild to severe. The most serious concern is liver damage, which can be life-threatening and was the main reason this medication was withdrawn from most markets.

Here are the common side effects you might experience:

• Nausea and vomiting
• Diarrhea
• Loss of appetite
• Abdominal pain
• Dizziness
• Headache
• Fatigue

The serious side effects that require immediate medical attention include:

• Yellowing of skin or eyes (jaundice)
• Dark urine
• Severe abdominal pain
• Unusual fatigue or weakness
• Loss of appetite lasting several days
• Slow heart rate
• Difficulty breathing

These serious symptoms could indicate liver damage or other potentially dangerous complications that need immediate medical care.

Who Should Not Take Tacrine?

Several groups of people should avoid tacrine due to increased risk of serious complications. Anyone with existing liver disease or a history of liver problems should not take this medication.

Other conditions that make tacrine unsuitable include:

• Active liver disease or elevated liver enzymes
• Severe heart problems or irregular heartbeat
• Active stomach ulcers
• Severe asthma or breathing problems
• Urinary blockage
• Seizure disorders

Pregnant and breastfeeding women should also avoid tacrine, as its effects on developing babies are not well understood.

Tacrine Brand Names

Tacrine was originally marketed under the brand name Cognex in the United States. This was the primary brand name used when the medication was still available.

However, since tacrine has been withdrawn from most markets due to safety concerns, these brand names are no longer in use. If you're looking for dementia treatment, your doctor will likely recommend newer, safer alternatives.

Tacrine Alternatives

Several safer and more effective alternatives to tacrine are now available for treating Alzheimer's disease and other forms of dementia. These newer medications have better safety profiles and are generally more effective.

Current alternatives include:

• Donepezil (Aricept) - also a cholinesterase inhibitor but much safer
• Rivastigmine (Exelon) - available as pills or patches
• Galantamine (Razadyne) - another cholinesterase inhibitor
• Memantine (Namenda) - works differently by blocking NMDA receptors
• Aducanumab (Aduhelm) - a newer, controversial option

These alternatives are preferred because they cause fewer serious side effects and don't carry the same risk of liver damage that made tacrine dangerous.

Is Tacrine Better Than Donepezil?

Donepezil is generally considered superior to tacrine in almost every way. While both medications work by the same mechanism, donepezil has a much better safety profile and is more convenient to take.

Donepezil only needs to be taken once daily, compared to tacrine's four times daily dosing. More importantly, donepezil doesn't cause the serious liver problems that made tacrine dangerous. Studies have also shown that donepezil is at least as effective as tacrine for treating Alzheimer's symptoms, if not more so.