Tacrine

Tacrine2DACS.svg

Tacrine is a cholinesterase inhibitor that was used as a medication for the treatment of Alzheimer's disease. It was the first drug approved by the Food and Drug Administration (FDA) for this purpose. Tacrine is known by its brand name, Cognex.

History

Tacrine was first synthesized in the 1940s and was initially investigated for its potential use in treating myasthenia gravis. However, it was not until the 1980s that its potential for treating Alzheimer's disease was explored. In 1993, Tacrine became the first drug approved by the FDA for the treatment of Alzheimer's disease.

Mechanism of Action

Tacrine works by inhibiting the enzyme acetylcholinesterase, which breaks down the neurotransmitter acetylcholine. By preventing the breakdown of acetylcholine, Tacrine increases the levels of this neurotransmitter in the brain, which is thought to help alleviate some of the symptoms of Alzheimer's disease.

Pharmacokinetics

Tacrine is administered orally and is rapidly absorbed from the gastrointestinal tract. It undergoes extensive first-pass metabolism in the liver, primarily by the enzyme cytochrome P450 1A2 (CYP1A2). The drug has a relatively short half-life, necessitating multiple doses throughout the day to maintain therapeutic levels.

Side Effects

The use of Tacrine is associated with several side effects, the most common of which are gastrointestinal disturbances such as nausea, vomiting, and diarrhea. More serious side effects include hepatotoxicity, which has limited its use. Regular monitoring of liver function tests is required for patients on Tacrine therapy.

Discontinuation

Due to its side effects and the development of newer cholinesterase inhibitors with better safety profiles, Tacrine has largely fallen out of favor and is no longer widely used. Other drugs such as donepezil, rivastigmine, and galantamine have largely replaced Tacrine in the treatment of Alzheimer's disease.

See Also

• Alzheimer's disease
• Cholinesterase inhibitor
• Donepezil
• Rivastigmine
• Galantamine