What Is Galantamine?
Galantamine hydrobromide (Galantamine HBr) is a medication that can be used to treat the symptoms of people with Alzheimer’s disease. It is an acetylcholinesterase inhibitor.
Galantamine can be obtained from plants of the Amaryllidaceae family or through laboratory synthesis. The medication works by increasing the level of a certain chemical in the brain called acetylcholine, which facilitates the communication of nerve cells. This helps patients with Alzheimer’s disease with their memory and thinking.
The usage of Galantamine began in the 1950s in the Soviet Union. It was first isolated from bulbs of Galanthus nivalis in 1956 by D. Paskov, a Bulgarian chemist. The active ingredient was found to have acetylcholinesterase-inhibiting properties. This drug was developed in 1959, but full-scale manufacturing was optimized in the 1990s.
Is Galantamine FDA-Approved?
The FDA (The Food and Drug Administration) approved the medical use of Galantamine HBr in 2004.
How Does Galantamine HBr Work?
The exact cause of memory and thinking difficulties in Alzheimer’s is not completely understood. One key change in the brain is the death of nerve cells that respond to a chemical called acetylcholine, which is important for memory and learning. As more and more nerve cells die, symptoms of memory and thinking difficulties worsen.
Galantamine hydrobromide is a drug that helps raise levels of acetylcholine in the brain. It works by inhibiting the breakdown of acetylcholine, so that brain cells can communicate with each other. This can help improve memory and thinking in some patients. But Galantamine hydrobromide does not treat Alzheimer’s or stop its progression.
Uses
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Galantamine HBr is used to treat mild to moderate dementia in Alzheimer's disease.
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Galantamine is also used to treat memory impairments like dementia associated with Parkinson's disease, Down's syndrome, multiple sclerosis, and frontotemporal dementia.
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It also treats cognitive impairment associated with Lewy body disease, traumatic brain injury, electroconvulsive therapy, schizophrenia, and bipolar disorder.
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It is used to treat post-traumatic nerve palsy of the oculomotor and trochlear nerves.
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It is also used to manage acute scopolamine toxicity and organophosphorus poisoning.
Dosage:
Galantamine HBr is a prescription drug available in the form of tablets, extended-release capsules, and oral solution.
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The recommended initial dose of Galantamine tablets is 4 mg (milligram) twice a day, which is 8 mg daily.
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After four weeks, the dosage is increased to 8 mg twice daily (16 mg/day).
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After that, it is increased to 12 mg twice daily (24 mg/day) after four weeks of a 16 mg daily dosage.
Warnings:
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Skin Reactions: Galantamine can cause serious skin reactions like Stevens-Johnson syndrome and acute generalized exanthematous pustulosis. If such skin reactions are seen, the drug should be discontinued.
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Cardiovascular Conditions: Galantamine can cause bradycardia and AV (atrioventricular) node block. It can occur in patients with or without underlying cardiac conduction abnormalities. Hence, Galantamine can cause adverse effects on cardiac function.
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Gastrointestinal Conditions: Galantamine should be used cautiously in patients with stomach ulcers. It increases the risk of gastrointestinal bleeding and causes nausea, vomiting, diarrhea, anorexia, and weight loss.
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Genitourinary Conditions: Galantamine may cause bladder outflow obstruction.
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Neurological Conditions: Galantamine may cause seizures. Patients taking this drug should be monitored for seizures.
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Respiratory Conditions: It should be used cautiously in asthma or obstructive pulmonary disease patients to prevent adverse effects.
For Patients
Facts to Know Before Starting Galantamine HBr:
When and Why Switch to Galantamine HBr?
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Various medications are prescribed for treating Alzheimer's disease.
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Acetylcholinesterase inhibitors such as Donepezil, Galantamine, and Rivastigmine are commonly prescribed for Alzheimer's.
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All three drugs work in the same way.
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However, patients respond differently to each medication.
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Galantamine HBr may be chosen or substituted when a patient experiences insufficient benefit or intolerable side effects with another acetylcholinesterase inhibitor, as some individuals tolerate Galantamine better.
How Effective Is Galantamine HBr?
It has been reported that Galantamine HBr effectively prevents the progression of the disease by keeping the functioning neurons intact. It prevents the worsening of dementia in mild to moderate types of Alzheimer's disease.
Things to Inform the Doctor Before Galantamine HBr Is Prescribed:
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Galantamine should not be used if the patient is allergic to it.
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It is not known if Galantamine can harm an unborn baby. It should not be used if the patient is pregnant or planning to become pregnant.
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Breastfeeding should be avoided while taking this drug.
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The presence of heart diseases, kidney diseases, liver diseases, stomach ulcers, asthma or chronic obstructive pulmonary disease (COPD), seizures, and urinary problems should be informed.
How to Take Galantamine HBr?
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Galantamine HBr should be taken as prescribed by the doctor.
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The extended-release capsules work better with food.
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It should be taken with food. Galantamine capsules should be swallowed as a whole.
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It should not be chewed, broken, or opened.
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The oral solution should be measured with a spoon or cup before consumption.
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All the instructions should be carefully followed while taking Galantamine.
Things to Be Followed While Under Galantamine HBr:
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It is important to follow all the doctor's instructions and visit regularly to monitor the disease's progress and any side effects.
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Galantamine may harm the unborn baby. If a woman becomes pregnant during the treatment, inform the doctor.
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Breastfeeding is not advisable, and it should be avoided while taking Galantamine.
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Galantamine can cause cardiac disorders. If symptoms like chest pain, breathing difficulty, and swelling of hands and feet occur, they should be informed.
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Galantamine can cause allergic reactions like rashes, hives, breathing difficulties, and swelling of the face, hands, and feet. If such reactions develop, they should be informed.
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Galantamine HBr should be stopped before undergoing surgery. So, informing the surgeon about the consumption of the drug is important.
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If this drug is stopped or the dosage is missed, it should be consulted with the doctor before starting it again.
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It can cause various adverse effects. Any such effects or abnormalities should be reported to the doctor.
Advice for Caregivers:
The caregivers should inform the doctor if the patient develops allergic reactions like rashes, hives, breathing difficulties, or other symptoms like chest pain, seizures, or other abnormalities.
Things to Do After Taking Galantamine HBr:
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If there are any noticeable symptoms or unwanted effects after taking Galantamine HBr, they should inform their doctor.
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If allergic reactions or symptoms such as chest pain, breathing difficulties, or seizures develop, they should inform the doctor immediately.
Diet Modifications:
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Dietary restrictions or modifications are not essential unless recommended by the doctor.
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A healthy and balanced diet can be followed while taking Galantamine.
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However, the use of alcohol or tobacco is not recommended while taking this drug.
Look Out for the Side Effects:
The patients should familiarize themselves with the common and rare side effects of Galantamine HBr so that the symptoms can be easily identified. If side effects are present, they should be reported to the doctor.
The common side effects include the following:
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Serious skin reactions.
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Reduced heart rate and chest pain.
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Reduced urine output.
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Blood in the urine.
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Bloody stools.
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Yellowish discoloration of the skin or eyes.
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Dehydration.
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Lightheadedness.
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Fever and sore throat.
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Nausea, vomiting, and diarrhea.
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Headache.
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Dizziness.
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Weight loss.
Less common side effects include the following:
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Chest pain or discomfort.
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Shortness of breath.
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Confusion.
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Blurred vision.
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Dry mouth.
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Rapid breathing.
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Nervousness.
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Unusual tiredness.
Staying on Galantamine HBr
Tips to Stay on Track:
Improvement in the symptoms of Alzheimer's disease can be experienced after taking Galantamine. If any side effects occur while taking this drug, it is essential to inform the doctor. The dosage schedule should be carefully followed. It should be consulted with the doctor about missing a dose.
Things to remember,
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Sticking to the dosage schedule of Galantamine is important because missing the dosage schedule will affect the treatment outcome.
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It is essential to follow up regularly with the doctor and inform them about the improvement in the symptoms of Alzheimer's disease.
For Doctors
Indications and Uses:
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Galantamine HBr is used to treat mild to moderate dementia in Alzheimer's disease.
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Galantamine is also used to treat memory impairments like dementia associated with Parkinson's disease, Down's syndrome, multiple sclerosis, and frontotemporal dementia.
-
It also treats cognitive impairment associated with Lewy body disease, traumatic brain injury, electroconvulsive therapy, schizophrenia, and bipolar disorder.
-
It is used to treat post-traumatic nerve palsy of the oculomotor and trochlear nerves.
-
It is also used to manage acute Scopolamine toxicity and organophosphorus poisoning.
Mechanism of Action
The exact reason behind the cognitive impairment in Alzheimer's disease has not been established. The loss of cholinergic function characterizes it. It has been studied that the acetylcholine-producing neurons undergo degeneration in the brains of Alzheimer's patients.
The degree of cognitive impairment and density of amyloid plaques depend on cholinergic loss.
Galantamine HBr is a competitive and reversible inhibitor of acetylcholinesterase. The exact mechanism of action of Galantamine has yet to be established.
It was observed that Galantamine reversibly inhibits the hydrolysis of acetylcholine by cholinesterase. This inhibition increases the concentration of acetylcholine, thereby enhancing the cholinergic function. This mechanism prevents cholinergic loss by maintaining the cholinergic neurons intact. However, Galantamine does not alter the course of underlying dementia.
Dosage
Galantamine HBr is a prescription drug for tablets, extended-release capsules, and oral solutions.
The recommended initial dose of Galantamine tablets is 4 mg (milligram) twice a day, which is 8 mg daily. After four weeks, the dosage is increased to 8 mg twice daily (16 mg/day). After that, it is increased to 12 mg twice daily (24 mg/day) after four weeks of a 16 mg daily dosage.
Considerations for Administration:
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Dosage should be increased depending on the improvements and tolerability of the previous dose.
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Galantamine tablets should be prescribed twice a day.
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If the therapy was interrupted for over three days, it should be restarted with the lowest dose and escalated to the usual dose.
Contraindications:
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Galantamine may harm the unborn baby. It is contraindicated in pregnant women and those planning for pregnancy.
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Breastfeeding is not advisable, and it should be avoided while taking Galantamine.
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Galantamine can cause cardiac disorders. It should be used cautiously in patients with or without underlying cardiac disorders.
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Galantamine can cause allergic reactions like rashes, hives, breathing difficulties, and swelling of the face, hands, and feet. It is contraindicated in patients with Galantamine allergy.
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Galantamine HBr can alter the effects of anesthesia. So, it should be stopped before undergoing surgery.
Pharmacodynamics:
Galantamine HBr is a competitive and reversible inhibitor of acetylcholinesterase. It works by inhibiting the hydrolysis of acetylcholine by cholinesterase to increase the concentration of acetylcholine, thereby enhancing the cholinergic function. It promotes improvements in cognition and behavioral symptoms of Alzheimer's disease.
Pharmacokinetics:
Absorption and Bioavailability
It has a high oral bioavailability of about 90 %. It is equivalent to oral solutions and tablets. Peak plasma concentrations are achieved within 1 to 4.5 hours after administration. Maximum inhibition of acetylcholinesterase activity was achieved one hour after a single oral dose of 8 mg.
Distribution
Galantamine is mainly distributed in the blood cells in the whole blood. The plasma protein binding of Galantamine is 18 % at therapeutic doses.
Elimination
Galantamine is metabolized in the liver by the cytochrome isoenzymes and eliminated in the urine. The elimination half-life of Galantamine is about seven hours.
Results from Clinical Trials:
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Five randomized, double-blind, placebo-controlled studies demonstrated the effectiveness of Galantamine HBr in Alzheimer's patients.
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Studies showed that Galantamine improves cognitive function significantly. Extended-release tablets are more effective in causing a significant improvement.
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Studies demonstrated that Galantamine works by inhibiting the hydrolysis of acetylcholine by cholinesterase to increase the concentration of acetylcholine, thereby enhancing the cholinergic function.
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It promotes improvements in cognition and behavioral symptoms of Alzheimer's disease.
Interactions With Other Drugs:
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Galantamine interferes with the activity of anticholinergic medications.
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It interacts with succinylcholine and other cholinesterase inhibitors.
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It also interacts with other drugs such as Ketoconazole, Erythromycin, Paroxetine, H2 antagonists, Memantine, Digoxin, and Warfarin.
Other Specifications:
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Cardiovascular Conditions: Galantamine can cause bradycardia and AV (atrioventricular) node block. It can occur in patients with or without underlying cardiac conduction abnormalities.
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Gastrointestinal Conditions: Galantamine increases the risk of gastrointestinal bleeding and causes nausea, vomiting, diarrhea, anorexia, and weight loss.
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Genitourinary Conditions: Galantamine may cause bladder outflow obstruction.
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Neurological Conditions: Galantamine may cause seizures.
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Respiratory Conditions: To prevent adverse effects, Galantamine should be used cautiously in asthma or obstructive pulmonary disease patients.
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Hepatic Impairment: Galantamine tablets are not recommended for patients with severe hepatic impairment. A dosage adjustment is required in patients with moderate impairment.
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Renal Impairment: Galantamine tablets are not recommended for patients with less than 9 mL per minute of creatinine clearance. A dosage adjustment is required in patients with a clearance rate of 59 mL per minute.
Use in Special Populations:
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Pregnancy: Galantamine may harm the unborn baby. It should not be used in pregnant women or those planning to become pregnant.
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Lactation: The presence of Galantamine in breast milk has not been established. But breastfeeding should not be done while taking this tablet.
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Pediatric Use: The safety and effectiveness of Galantamine in the pediatric population have not been established.
- Geriatric Use: Galantamine tablets are effectively used to treat mild to moderate dementia in Alzheimer's disease.
