Donepezil is a drug that was developed by Pfizer and his partner Eisai. In the market, it is known as Aricept and is presently sold as a generic drug by many suppliers. It is an acetylcholinesterase inhibitor that is mainly used as a palliative treatment of Alzheimer’s disease. This drug was the best-selling drug for Alzheimer’s as of 2011. Its maiden generic form was unveiled in November 2010 when the US Food and Drug Administration(FDA) approved a preparation that was created by the Ranbaxy Laboratory. Another formulation that was the second generic formulation was tentatively approved by the FDA in April 2011. This second drug was made by Wockhardt. Since then, the drug has basically been sold as a generic.
How does it work?
This drug works by reversibly inhibiting the enzyme acetylcholinesterase in the brain. The enzyme works by breaking down acetylcholine which is an important neurotransmitter. Since it reversibly inhibits the enzyme, the drug may work by allowing an increased concentration of the neurotransmitter acetylcholine in the brain. This may then improve the cholinergic functions of the brain.
In patients with Alzheimer’s, there is distinct shortage of acetylcholine which is related to learning and memory. Thus the drug donepezil works by improving the presence of this important neurotransmitter in such patients.
The benefits of Donepezil
Studies have indicated that this drug is capable of enhancing cognition. When a controlled clinical trial was conducted in more than 900 subjects, it was shown that over eighty per cent of them taking the drug either enhanced or displayed no further revelation in cognition tests over the progression of the research. In the same study but dealing with its function in patients, which encompasses behavior, cognition, daily living activities, and general function, the researchers discovered an improvement of nearly two times in the subjects who were taking Aricept compared to those who were not taking it. The comparison was made in the aftermath of a 24-week treatment period.
Therefore, this drug is utilized in the enhancement of cognition in patients with Alzheimer. Moreover it has been shown to also have positive effects when it comes to treating patients with vascular dementia as well as dementia associated with Parkinsonism. It achieves all this because it has the capacity to reversibly inhibit the acetylcholinesterase enzyme, which translates to increased acetylcholine in the brain.
The side effects
Because of its mechanism of action, Donepezil has been shown to produce side-effects. Diarrhea, loss of appetite, muscle cramps, trouble in sleeping, vomiting, unusual tiredness or lethargy, and nausea are some of the most common side effects associated with this drug. Users of the drug also reported weight loss, unusual bleeding or bruising, pain, mental depression, headache, frequent urination, drowsiness and dizziness as being some of the less common side effects. When overdosed, this drug may also produce symptoms such as increased sweating, convulsions, troubled breathing as well as severe vomiting.
In all those cases, the person is advised to seek medical attention as soon as possible.
In adult patients with Alzheimer’s, the effective dosage of donepezil was indicated to be about 5mg or even 10mg which are administered once per day. This is in the treatment of mild to moderate Alzheimer conditions. However, the greater 10mg dose did not give a significant improvement in the efficacy of the drug. This is despite the fact that suggestions have indicated that the 10mg dose might have a greater clinical significance. It is a matter of personal choice and preference as to whether one uses 5mg or 10mg. Since the drug undergoes phase I metabolism in the liver, it has to be used with caution. It is also important to note that the 5mg per day is the recommended starting dose for this drug.
This drug can be administered either with or without food. It should be swallowed whole with water and should NEVER be crushed as this increases its absorption rate.