Generic Name

Galantamine Hydrobromide

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Classification

FDA Approved Indications

• Mild to moderate Alzheimer’s disease

Mechanism of Action

Inhibits cholinesterase enzymes, resulting in increased levels of acetylcholine in the brain, which may improve cognitive function.

Dosage and Administration

Adult: Start with 4 mg twice daily; titrate up to 12 mg twice daily after 4 weeks based on response and tolerability.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution; start at lower doses due to potential for increased sensitivity.

Renal Impairment: Adjust dose based on severity; consult specific guidelines.

Hepatic Impairment: Data limited; use with caution and monitor for side effects.

Pharmacokinetics

Absorption: Well absorbed orally, with high bioavailability.

Distribution: Widely distributed in tissues including the brain.

Metabolism: Metabolized in the liver via CYP2D6 and CYP3A4 pathways.

Excretion: Excreted mainly in urine, largely unchanged.

Half Life: Approx. 7 hours.

Contraindications

• Hypersensitivity to galantamine or other cholinesterase inhibitors.

Precautions

• Use with caution in patients with cardiac disease, peptic ulcer, urinary outflow issues, or convulsive disorders; monitor for bradycardia and gastrointestinal side effects.

Adverse Reactions - Common

• Nausea (Common)
• Insomnia (Common)
• Vomiting (Common)
• Dizziness (Common)

Adverse Reactions - Serious

• Bradycardia, heart block (Uncommon)
• Seizures (Rare)
• Gastrointestinal bleeding in high-risk patients (Rare)

Drug-Drug Interactions

• Other cholinesterase inhibitors, anticholinergic drugs, drugs affecting CYP2D6 or CYP3A4 enzymes.

Drug-Food Interactions

• No significant interactions identified.

Drug-Herb Interactions

• Avoid use with herbs containing cholinergic activity (e.g., ginseng).

Nursing Implications

Patient/Family Teaching

• Take medication as directed, with food to minimize gastrointestinal upset.
• Report signs of bradycardia, fainting, or gastrointestinal bleeding.
• Do not stop medication abruptly.

Special Considerations

Black Box Warnings:

• Potential for gastrointestinal bleeding, especially in high doses or in patients at risk.

Genetic Factors: Metabolism may be influenced by CYP2D6 and CYP3A4 polymorphisms.

Lab Test Interference: No significant interference reported.

Overdose Management

Signs/Symptoms: Nausea, vomiting, dizziness, bradycardia, hypotension, seizures.

Treatment: Supportive care, atropine for bradycardia, possibly activated charcoal, and gastric lavage if recent ingestion.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable for the duration of the labeled expiration date.