Medozil (Donepezil Hydrochloride Monohydrate)

• Donepezil is used in the management of Alzheimer’s disease, a neurodegenerative disorder affecting memory and cognition.
• Alzheimer’s disease (mild): improves short‑term memory and attention.
• Alzheimer’s disease (moderate): supports daily living activities and slows functional decline.
• Alzheimer’s disease (severe): helps maintain residual cognitive abilities and may reduce behavioral symptoms.

• Donepezil reversibly inhibits acetylcholinesterase, the enzyme responsible for breaking down acetylcholine in the synaptic cleft. By reducing enzyme activity, it increases the concentration of acetylcholine in the brain, enhancing cholinergic neurotransmission and thereby improving cognitive processes that are compromised in Alzheimer’s disease.

Donepezil may cause a range of adverse reactions, from mild to serious.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Diarrhea: loose stools occurring shortly after dosing.
• Insomnia: difficulty falling or staying asleep.
• Muscle cramps: occasional skeletal muscle discomfort.
• Fatigue: feeling unusually tired or weak.
• Loss of appetite: reduced desire to eat.

Serious or Rare Side Effects

• Bradycardia: markedly slowed heart rate requiring medical attention.
• Syncope: fainting episodes, especially in patients with cardiac disease.
• Severe vomiting: persistent emesis leading to dehydration.
• Hepatic injury: abnormal liver function tests or hepatitis.
• Seizures: rare convulsive events.
• Gastrointestinal bleeding: occult or overt bleeding in the GI tract.

• When prescribing or dispensing Donepezil, several safety considerations are important.
• Renal impairment: monitor renal function and adjust therapy if needed.
• Cardiac conduction disorders: evaluate for bradyarrhythmias before initiation.
• Gastrointestinal ulcer disease: use with caution due to increased ulcer risk.
• Seizure disorders: observe for any increase in seizure frequency.
• Pregnancy: safety not established; use only if potential benefit justifies risk.
• Store at room temperature: keep in original container, protect from moisture and direct sunlight.

Donepezil can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Strong anticholinergics: may diminish therapeutic effect.
• Beta‑blockers: can exacerbate bradycardia.
• CYP2D6 inhibitors (e.g., paroxetine, fluoxetine): increase plasma concentrations of Donepezil.

Moderate Interactions (Monitor Closely)

• NSAIDs: elevate risk of gastrointestinal bleeding.
• Anticoagulants (e.g., warfarin): may enhance anticoagulant effect.
• Other cholinesterase inhibitors: additive cholinergic activity may increase side‑effect burden.