GALANTAMINE HYDROBROMIDE

GALANTAMINE HYDROBROMIDE
(ga-lan'ta-meen)
Razadyne, Razadyne ER
Classifications: cholinesterase inhibitor; central acting; antidementia agent;
Therapeutic: antialzheimer; antidementia; cholinesterase inhibitor
Prototype: Donezepril HCl
Pregnancy Category: B

Availability

4 mg, 8 mg, 12 mg tablets; 8 mg, 16 mg, 24 mg extended release capsules; 4 mg/mL oral solution

Action

Competitive and reversible inhibitor of acetylcholinesterase which is the enzyme responsible for the hydrolysis (breakdown) of the neurotransmitter, acetylcholine. The cholinergic system is known to be important in the processing needed for attention, memory, and modulation of excitatory neurotransmission.

Therapeutic Effect

In Alzheimer's disease cholinesterase inhibitors are designed to offset loss of presynaptic cholinergic function, slowing decline of memory and maintaining ability to perform functions of daily living.

Uses

Treatment of mild to moderate dementia of Alzheimer's type.

Unlabeled Uses

Vascular dementia.

Contraindications

Hypersensitivity to galantamine. Not recommended with severe renal or hepatic impairment; lactation, or in children.

Cautious Use

Bradycardia, heart block or other cardiac conduction disorders; asthma, COPD; potential bladder outflow obstruction; a history of seizures or GI bleeding; concurrent use of drugs which slow the heart rate, drugs which may cause syncope, NSAIDs, or neuromuscular blocking agents during anesthesia, pregnancy (category B).

Route & Dosage

Alzheimer's Disease
Adult: PO Initiate with 4 mg b.i.d. times at least 4 wks, if tolerated may increase by 4 mg b.i.d. q4wk to target dose of 12 mg b.i.d. (8–16 mg b.i.d.)

Hepatic Impairment
Not recommended with severe hepatic impairment.

Renal Impairment
Cl_cr <9 mL/min: not recommended

Administration

Oral

Give with meals (breakfast and dinner) to reduce the risk of nausea.
Extended release capsules should be swallowed whole and not crushed or chewed.
Make increases in dosage increments at 4-wk intervals.
If drug is interrupted for several days or more, restart at the lowest dose and gradually increase to the current dose.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Weight loss, fatigue, rhinitis, syncope, malaise, asthenia, fever. CNS: Dizziness, headache, depression, insomnia, somnolence, tremor. CV: Bradycardia, chest pain. GI: Nausea, vomiting, diarrhea, anorexia, abdominal pain, dyspepsia, flatulence. Hematologic: Anemia. Urogenital: UTI, hematuria, incontinence. Nervous System: Tinnitus, leg cramps. Other: Increased mortality in patients with mild cognitive impairment.

Interactions

Drug: Additive effects with other cholinesterase inhibitors (e.g., succinylcholine, bethanecol); cimetidine, erythromycin, ketoconazole, paroxetine may increase levels and toxicity.

Pharmacokinetics

Absorption: Rapidly and completely. Peak: 1 h. Distribution: Mainly distributes to red blood cells. Metabolism: In liver by CYP2D6 and CYP3A4. Elimination: 95% in urine. Half-Life: 7 h (4.4–10 h).

Nursing Implications

Assessment & Drug Effects

Monitor cardiovascular status including baseline and periodic EKG and BP readings. Assess for postural hypotension.
Monitor respiratory status; report worsening of preexisting asthma or COPD.
Monitor I&O rates and pattern for urinary incontinence or urinary retention.
Monitor appetite and food intake. Weigh weekly and report significant weight loss.
Lab tests: Baseline ALT/AST, BUN and creatinine; periodic blood glucose, alkaline phosphatase, urinalysis, stool for occult blood.

Patient & Family Education

Report any of the following to a health care provider immediately: loss of weight, urinary retention, chest pain, palpitations, difficulty breathing, fainting, dark stools, blood in the urine.

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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