manifest different side-effects and efficacy (Bentué-Ferrer, Tribut, Polard & Allain, 2003). On
the other hand, memantine is the latest drug approved by the FDA in treating dementia in
patients with Alzheimer's disease. This drug improves memory by blocking the action of
glutamate, a natural substance released in the brain. This substance has been found to be
associated with the principal symptoms of Alzheimer's disease, especially dementia (Barry et al.,
2003). Regarding efficacy, donepezil is considered to exhibit the highest efficacy compared to all
the alternative drugs. This is so because it is approved for use in all stages of Alzheimer's
disease. It can be used at mild, moderate and severe stages of the disease. In contrast, alternative
drugs are approved for use in either one or two stages of Alzheimer's disease. For instance,
galantamine, rivastigmine and tacrine are approved for treatment during mild to moderate stages
of the disease, whereas memantine is approved for moderate to severe stages of Alzheimer's
disease (Feret and Dicks, 2004).
Donepezil, like the other cholinesterase inhibitors exhibit side effects which expose
patients to health consequences. Some of the severe side effects of donepezil are slow heart rate,
chest pain, fainting, respiratory problems, seizures, lower back pain, bloody vomit, and fever. It
is also known to cause urinary tract problems, discoloration of the skin and passing bloody stool.
Other common side effects include loss of appetite, muscle cramps, weight loss, excessive
tiredness, headache, dizziness, and insomnia. In addition, it causes vomiting, diarrhea, joint pain,
mood swing, hallucination, nervousness, depression, and hallucinations (Saltiel, 2014). In some
patients, donepezil has been found to cause weight loss although the mechanism has ne been
In comparison, donepezil and all the other cholinesterase inhibitors cause nausea, loss of
appetite, vomiting and changes in bowel movements. Memantine, a non-cholinesterase inhibitor
is characterized with constipation, headache, dizziness, and confusion.
Donepezil is also known to have some contra-indications. For instance, donepezil is not
recommended for pregnant mothers, as well as patients with allergic reactions to piperidine
derivatives. It is also known to interact with antihistamines, NSAIDs such as naproxen and
ibuprofen, and carbamazepine. On the other hand, this drug is not recommended for patients with
some disease conditions such as Parkinson's disease, heart disease, asthma, obstructive
pulmonary disease, and ulcers. Therefore, it shares common characteristics with galantamine,
rivastigmine and tacrine. However, its contra-indications are more compared to those observed
In formulation, donepezil is available two dosage forms. It exists as a tablet or a tablet
disintegrating form. In both formulations, the drug comprises of a convenient dosage of 23 mg so
the tablet is swallowed wholly at once per dosage. This enhances the patients' compliance to the
drug administration. On the other hand, rivastigmine is available in capsules and solution forms
with dosages of 1.5, 3, 4.5, and 6 mg for capsules and 2 mg/ml for solutions. This drug is
supposed to be taken twice daily similar to galantamine which is available in tablet formulation.
Memantine is available in a liquid form and it is administered orally (Barry et al., 2003). In
comparison, donepezil exists in a more convenient dosage compared to all the other alternative
drugs used in treating dementia in patients suffering from Alzheimer's disease.
Regarding formulation issues, donepezil is known to be stable, and it is stored at room
temperature. All alternative drugs are also stored at room temperature so it does not reflect any
formulation issue with storage.
From a critical point of view, donepezil should be given in preference to all other
alternative drugs for treating Alzheimer's disease. This is so because, the drug has been found to
exhibit a high efficacy compared to all other drugs including memantine which has a different
mode of action from cholinesterase inhibitors. Donepezil is the only drug approved for treatment
of Alzheimer's disease in all stages. For matters of priority, donepezil should be used as the first
line drug in the treatment of the disease, whereas memantine should be used as second line drug
because it is recommended for moderate to severe stages of Alzheimer's disease.
In addition, its mode of action follows simple pharmacokinetics which does not cause
negative consequences the nervous system. Compared to the other cholinesterase inhibitors,
donepezil has not been found to cause devastating health consequences as it has been observed
with tacrine. Tacrine is no longer prescribed for the treatment of Alzheimer's disease owing to its
damage to the liver.
The fifth reason why donepezil should be given preference to all other drugs is its
formulations. Foremost, it is available in two convenient formulations; tablet and tablet
disintegrating forms. These forms contain adequate dosages of 23 mg which is adequate for a
single daily dosage compared to the other drugs which are administered twice to thrice daily. As
such, it serves as a simple and convenient dosage for patients.
Excerpt out of 5 pages
- Quote paper
- Patrick Kimuyu (Author), 2018, Questions on the Prescription of Donepezil in the Treatment of Alzheimer's Disease, Munich, GRIN Verlag, https://www.grin.com/document/388474