Generic Name : Donepezil.

Trade Name    : Aricept.

Drug Class      :  Acetylcholinesterase Inhibitors ( Central).

Forms Of The Drug

  1. Tablet: 5mg, 10mg, 23mg.

Mechanism Of Action

Donepezil is a medication primarily used in the management of Alzheimer’s disease, a neurodegenerative disorder characterized by cognitive decline and memory impairment. It belongs to a class of drugs called acetylcholinesterase inhibitors, and its mechanism of action involves several key steps:

  1. Acetylcholine Modulation: In Alzheimer’s disease, there is a decrease in the levels of acetylcholine, a neurotransmitter crucial for memory, learning, and cognitive function. Donepezil works by inhibiting the enzyme acetylcholinesterase (AChE) in the brain.
  2. Inhibition of Acetylcholinesterase: Acetylcholinesterase is responsible for breaking down acetylcholine after it transmits signals between nerve cells. By inhibiting AChE, donepezil increases the availability and duration of acetylcholine in the synaptic cleft, enhancing cholinergic neurotransmission.
  3. Enhanced Cholinergic Function: Donepezil’s inhibition of acetylcholinesterase leads to an accumulation of acetylcholine in the synapses. This accumulation improves cholinergic signaling and helps to compensate for the decreased levels of acetylcholine seen in Alzheimer’s disease.
  4. Potential Neuroprotective Effects: There’s ongoing research into whether acetylcholinesterase inhibitors like donepezil may have additional neuroprotective effects beyond just enhancing neurotransmission. These potential effects might involve supporting neuronal health and function, contributing to slowing the progression of Alzheimer’s disease.
  5. Symptomatic Improvement: By increasing the availability of acetylcholine in the brain, donepezil aims to improve cognitive function, memory, and other aspects of mental clarity in individuals with Alzheimer’s disease. It doesn’t cure the disease but may help manage its symptoms.

Indications

  1. Alzheimer’s disease.
  2. Mild Cognitive Impairment (Off-label).

Contraindications

  1. Hypersensitivity.
  2. Bradycardia or Heart Block.
  3. Asthma and Chronic Obstructive Pulmonary Disease (COPD).
  4. Gastrointestinal or Urinary Obstruction.
  5. Seizure Disorders.
  6. Certain Neurological Conditions.
  7. Use with Certain Medications: Donepezil may interact adversely with certain medications, such as anticholinergic drugs, antispasmodics, and some psychiatric medications.

Side Effects

  1. Nausea (3-19%).
  2. Diarrhea (5-15%).
  3. Insomnia (2-14%).
  4. Accident (7-13%).
  5. Infection (11%).
  6. Headache (3-10%).
  7. Vomiting (3-8%).
  8. Cramping (3-8%).
  9. Fatigue (3-8%).
  10. Anorexia (2-8%).
  11. Hypertension (3% ).
  12. Abnormal dreams (3%).
  13. Hallucinations (3%).
  14. Confusion (2%).
  15. Syncope (2%).

Drug Interactions

Other drugs that can interact with it.

  1. Anticholinergic Medications: Drugs with anticholinergic effects, such as atropine, scopolamine, certain antihistamines, and some psychiatric medications.
  2. Antispasmodic Medications: Concurrent use of Donepezil with antispasmodic drugs, like oxybutynin or dicyclomine.
  3. Quaternary Ammonium Compounds: Drugs like succinylcholine (a muscle relaxant) and certain local anesthetics.
  4. Tricyclic Antidepressants: Tricyclic antidepressants, such as amitriptyline or imipramine.
  5. Certain Antibiotics: Some antibiotics, particularly those in the class of aminoglycosides.
  6. Other Cholinesterase Inhibitors: Concurrent use of Donepezil with other cholinesterase inhibitors, such as rivastigmine or galantamine.
  7. Guanidine Derivatives.

Precautions

  1. Pregnancy: Category C.
  2. Lactation: Given Donepezil’s potential to pass into breast milk and its effects on the central nervous system, healthcare providers may weigh the potential risks to the nursing infant against the benefits of treatment for the mother. The decision to use Donepezil during breastfeeding should consider the necessity of treatment and the availability of safer alternatives.

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