DONEPEZIL HYDROCHLORIDE

(don-e'pe-zil)

Aricept, Aricept ODT
Classifications: cholinergic, central acting; cholinesterase inhibitor;
Therapeutic: antidementia
Pregnancy Category: C

Availability

5 mg, 10 mg tablets and orally disintegrating tablets

Action

In early stages of Alzheimer's disease, pathologic changes in neurons result in deficiency of acetylcholine. Aricept, a cholinesterase inhibitor, presumably elevates acetylcholine concentration in the cerebral cortex by slowing degrading acetylcholine released by remaining intact neurons.

Therapeutic Effect

Improves global function, cognition, and behavior of patients with mild to moderate Alzheimer's.

Uses

Mild, moderate or severe dementia of Alzheimer's type.

Unlabeled Uses

Vascular dementia, poststroke aphasia, memory improvement in multiple sclerosis patients.

Contraindications

Hypersensitivity to donepezil or tracine; pregnancy (category C), lactation; children; GI bleeding, jaundice.

Cautious Use

Anesthesia, sick sinus rhythm, AV block, bradycardia, cardiac arrhythmias, cardiac disease, hypotension; hyperthyroidism, history of ulcers, abnormal liver function; patients with asthma or obstructive pulmonary disease, history of seizures, seizures, urinary tract obstruction, intestinal obstruction; diarrhea, emesis, GI disease, renal failure, renal impairment, surgery.

Route & Dosage

Alzheimer's Disease Related Dementia (Mild to Moderate)
Adult: PO 5–10 mg h.s.

Alzheimer's Disease Related Dementia (Severe)
Adult: PO 10 mg q.d.

Administration

Oral

Give at h.s. just prior to going to bed.
Increase dosage to 10 mg ONLY after 4–6 wk of therapy with the 5-mg dose.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Headache, fatigue. CNS: Insomnia, dizziness, depression, tremor, irritability, vertigo, ataxia. CV: Syncope, hypertension, atrial fibrillation, hot flashes, hypotension. GI: Nausea, diarrhea, vomiting, muscle cramps, anorexia, GI bleeding, bloating, fecal incontinence, epigastric pain. Respiratory: Dyspnea. Skin: Pruritus, sweating, urticaria. Other: Ecchymoses, muscle cramps, dehydration, blurred vision, urinary incontinence, nocturia.

Interactions

Drug: Ketoconazole, quinidine may inhibit donepezil metabolism; carbamazepine, dexamethasone, phenobarbital, phenytoin, rifampin may increase donepezil elimination; donepezil may interfere with the action of anticholinergic agents.

Pharmacokinetics

Absorption: Rapidly absorbed from GI tract. Peak: 3–4 h. Distribution: 96% protein bound. Metabolism: Metabolized in the liver by CYP2D6 and CYP3A4 to at least 2 active metabolites. Elimination: Primarily in urine. Half-Life: 70 h.

Nursing Implications

Assessment & Drug Effects

Monitor therapeutic effectiveness: Improvement as noted on the Alzheimer's Disease Assessment Scale.
Monitor closely for S&S of GI ulceration and bleeding, especially with concurrent use of NSAIDS.
Monitor carefully patients with a history of asthma or obstructive pulmonary disease.
Monitor cardiovascular status; drug may have vagotonic effect on the heart, causing bradycardia, especially in presence of conduction abnormalities.

Patient & Family Education

Exercise caution. Fainting episodes related to slowing the heart rate may occur.
Report immediately to physician any S&S of GI ulceration or bleeding (e.g., "coffee-grounds" emesis, tarry stools, epigastric pain).

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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