Rivastigmine
Rivastigmine
Definition
Rivastigmine is a drug used to treat symptoms of Alzheimer’s disease. In the United States, rivastigmine is sold as the brand name drug Exelon.
Purpose
Rivastigmine is used to treat symptoms of Alze-heimer’s disease in individuals with mild to moderate illness. It has also been used to treat dementia caused by other conditions such as Lewy body disease or following strokes. The drug may produce mild improvements in symptoms of thinking for a short period of time, but rivastigmine does not cure or stop progression of underlying diseases.
Description
The U.S. Food and Drug Administration approved rivastigmine in 2000 specifically for treating Alzheimer’s disease. In patients with Alzheimer’s disease, some cells in specific regions of the brain die. Because
of this cell death, these brain cells lose their ability to transmit nerve impulses. Brain cells normally transmit nerve impulses to one another by secreting various chemicals known as neurotransmitters.
Brain cells that make and secrete a neurotransmit-ter called acetylcholine are affected early in the course of Alzheimer’s disease. Rivastigmine prevents the breakdown of acetylcholine in the brain, thus temporarily increasing its concentration. In doing so, rivastigmine may improve the thinking process by facilitating nerve impulse transmission within the brain.
Rivastigmine is available as capsules in four different strengths and as an oral solution for use by people who have difficulty swallowing. Unlike some other drugs used to treat Alzheimer’s disease, rivastigmine is not broken down by the liver. As a result, it may be preferred in the treatment of people with Alzheimer’s disease who have liver disease.
Recommended dosage
The initial dosage of rivastigmine is 1.5 mg taken two times per day. If this dose is tolerated without difficulty, the dosage may be increased to 3 mg twice a day after at least two weeks at the lower dosage. Some people are unable to tolerate nausea, vomiting, anorexia, and weight loss that occur with higher dosages. If the drug does not cause significant adverse effects, the dose may be increased to 4.5 mg two times per day, followed by 6 mg two times per day. The dosage should be increased slowly, at two-week intervals. If side effects occur and cannot be tolerated, the drug may be stopped for several doses. When the drug is started again, the same dosage or the next lower dosage may be tried. The maximum daily dosage is 6 mg two times per day.
Precautions
Rivastigmine may slow heart rates, increase acid in the stomach, make urination difficult, cause breathing difficulties, and may possibly contribute to seizures. As a result, it should be used with close physician supervision and monitoring in people with certain heart conditions, tendencies to stomach ulcers, bladder obstruction, asthma or chronic obstructive pulmonary disease, and a history of seizure disorders.
Individuals taking rivastigmine should be reassessed periodically to determine whether the drug is providing any benefits. If caregivers feel the drug is no longer beneficial, it may be stopped.
KEY TERMS
Acetylcholine —A naturally occurring chemical in the body that transmits nerve impulses from cell to cell. Generally, it has opposite effects from dopamine and norepinephrine; it causes blood vessels to dilate, lowers blood pressure, and slows the heartbeat. Central nervous system well-being is dependent on a balance among acetylcholine, dopamine, serotonin, and norepinephrine.
Dementia —A group of symptoms (syndrome) associated with a progressive loss of memory and other intellectual functions that is serious enough to interfere with a person’s ability to perform the tasks of daily life. Dementia impairs memory, alters personality, leads to deterioration in personal grooming, impairs reasoning ability, and causes disorientation.
Lewy body disease —A type of dementia that resembles Alzheimer’s disease, but progresses more rapidly. Common symptoms include fluctuations in confusion and recurring visual hallucinations. In this disease, abnormal brain cells are distributed throughout the brain.
Milligram (mg)— One-thousandth of a gram. A gram is the metric measure that equals about 0.035 ounces.
Neurotransmitter —A chemical in the brain that transmits messages between neurons, or nerve cells.
Placebo —An inactive substance or preparation used as a control in experiments with human subjects to test the effectiveness of a drug or herbal preparation. Some patients may experience a medicinal response or experience side effects to a placebo simply because they have faith in its powers even though it contains no medicine.
Side effects
The most frequent side effects associated with rivastigmine involve stomach upset. Nausea, vomiting, anorexia, heartburn, and weakness occur in more than 5% of people and at twice the rate of people taking placebo pills. Dizziness and headaches also occur in more than 10% of people taking rivastigmine.
Other less common side effects include difficulty sleeping, confusion, depression, anxiety, sleepiness, hallucinations, tremors, fainting, aggression, constipation, gas, overwhelming fatigue, weight loss, increased sweating, and infections.
Interactions
Drugs such as dicyclomine may inhibit the effects of rivastigmine. Other drugs like bethanechol may possibly increase some of the side effects of rivastigmine. Rivastigmine may interact with some of the drugs used to relax muscles during surgery. The interaction increases the effects of both drugs.
Resources
BOOKS
Facts and Comparisons staff. Drug Facts and Comparisons. 6th ed. St. Louis, MO: Facts and Comparisons, 2002.
Tekin, Sibel, and Roger Lane. “Rivastigmine in the Treatment of Dementia Associated with Parkinson’s Disease: A Randomized, Double-Blind, Placebo-Controlled Study.” Progress in Neurotherapeutics and Neuropsychopharmacology. ed. Jeffrey L. Cummings. New York: Cambridge University Press, 2006.
PERIODICALS
de Tommaso, Marina, et al. “Two Years’ Follow-Up of Rivastigmine Treatment in Huntington Disease.” Clinical Neuropharmacology 30.1 (Jan.–Feb. 2007): 43–46.
Dybicz, Sharon B., et al. “Patterns of Cholinesterase-Inhibitor Use in the Nursing Home Setting: A Retrospective Analysis.” American Journal of Geriatric Pharmacotherapy 4.2 (June 2006): 154–60.
Eskander, Mariam F., et al. “Rivastigmine Is a Potent Inhibitor of Acetyl- and Butyrylcholinesterase in Alzheimer’s Plaques and Tangles.” Brain Research 1060. 1–2) (Oct. 2005): 144–52.
Farlow, Martin R., et al. “Efficacy of Rivastigmine in Alzheimer’s Disease Patients with Rapid Disease Progression: Results of a Meta-Analysis.” Dementia and Geriatric Cognitive Disorders 20.2–3 (Aug. 2005): 192–97.
Guillem, Francois, et al. “Are Cholinergic Enhancers Beneficial for Memory in Schizophrenia? An Event-Related Potentials (ERPs) Study of Rivastigmine Add-On Therapy in a Crossover Trial.” Progress in Neuro-Psychopharmacology & Biological Psychiatry 30.5 (July 2006): 934–45.
Miyasaki, J. M., et al. “Practice Parameter: Evaluation and Treatment of Depression, Psychosis, and Dementia in Parkinson Disease (an Evidence-Based Review): Report of the Quality Standards Subcommittee of the American Academy of Neurology.” Neurology 66.7 (Apr. 2006): 996–1002.
Ringman, John M., and Jeffrey L. Cummings. “Current and Emerging Pharmacological Treatment Options for Dementia.” Behavioural Neurology 17.1 (2006): 5–16.
Rongve, Arvid, and Dag Aarsland. “Management of Parkinson’s Disease Dementia: Practical Considerations.” Drugs and Aging 23.10 (2006): 807–22.
Sharma, Tonmoy, et al. “Cognitive Effects of Adjunctive 24-Weeks Rivastigmine Treatment to Antipsychotics in Schizophrenia: A Randomized, Placebo-Controlled, Double-Blind Investigation.” Schizophrenia Research 85.1–3 (July 2006): 73–83.
Takeda, A., et al. “A Systematic Review of the Clinical Effectiveness of Donepezil, Rivastigmine and Galantamine on Cognition, Quality of Life and Adverse Events in Alzheimer’s Disease.” International Journal of Geriatric Psychiatry 21.1 (Jan. 2006): 17–28.
Kelly Karpa, R.Ph., PhD
Ruth A. Wienclaw, PhD
Rivastigmine
Rivastigmine
Definition
Rivastigmine is a drug used to treat symptoms of Alzheimer's disease . In the United States, rivastigmine is sold as the brand name drug Exelon.
Purpose
Rivastigmine is used to treat symptoms of Alzeheimer's disease in individuals with mild to moderate illness. It has also been used to treat dementia caused by other conditions such as Lewy-body disease or following strokes. The drug may produce mild improvements in symptoms of thinking for a short period of time, but rivastigmine does not cure or stop progression of underlying diseases.
Description
The Food and Drug Administration approved rivastigmine in 2000 specifically for treating Alzheimer's disease. In Alzheimer's disease, some cells in specific regions of the brain die. Because of this cell death, these brain cells lose their ability to transmit nerve impulses. Brain cells normally transmit nerve impulses another by secreting various chemicals known as neurotransmitters .
Brain cells that make and secrete a neurotransmitter called acetylcholine are affected early in the course of Alzheimer's disease. Rivastigmine prevents the breakdown of acetylcholine in the brain, thus temporarily increasing its concentration. In doing so, rivastigmine may improve the thinking process by facilitating nerve impulse transmission within the brain.
Rivastigmine is available as capsules in four different strengths and as an oral solution for use by people who have difficulty swallowing. Unlike some other drugs used to treat Alzheimer's disease, the liver does not break down rivastigmine. As a result, it may be preferred in the treatment of people with Alzeheimer's disease who have liver disease.
Recommended dosage
The initial dosage of rivastigmine is 1.5 mg taken two times per day. If this dose is tolerated without difficulty, the dosage may be increased to 3 mg twice a day after at least two weeks at the lower dosage. Some people are unable to tolerate nausea, vomiting, anorexia, and weight loss that occur with higher dosages. If the drug does not cause significant adverse effects, the dose may be increased to 4.5 mg two times per day, followed by 6 mg two times per day. The dosage should be increased slowly, at two-week intervals. If side effects occur and cannot be tolerated, the drug may be stopped for several doses. When the drug is started again, the same dosage or the next lower dosage may be tried. The maximum daily dosage is 6 mg two times per day.
Precautions
Rivastigmine may slow heart rates, increase acid in the stomach, make urination difficult, cause breathing difficulties, and may possibly contribute to seizures . As a result, it should be used with close physician supervision and monitoring in people with certain heart conditions, those who are prone to stomach ulcers, people with bladder obstruction, individuals with asthma or chronic obstructive pulmonary disease, and people with a history of seizures disorders.
Individuals taking rivastigmine should be reassessed periodically to determine whether the drug is providing any benefits. If caregivers feel the drug is no longer beneficial, it may be stopped.
Side effects
The most frequent side effects associated with rivastigmine involve stomach upset. Nausea, vomiting, anorexia, heartburn, and weakness occur in more than 5% of people and at twice the rate of placebo pills. Dizziness and headaches also occur in more than 10% of people taking rivastigmine.
Other, less common, side effects are difficulty sleeping, confusion, depression, anxiety, sleepiness, hallucinations , tremors, fainting, aggression, constipation, gas, overwhelming fatigue , weight loss, increased sweating, and infections.
Interactions
Drugs such as dicyclomine may inhibit the effects of rivastigmine. Other drugs like bethanechol may possibly increase some of the side effects of rivastigmine. Rivastigmine may interact with some of the drugs used to relax muscles during surgery. The interaction increases the effects of both drugs.
Resources
BOOKS
Ellsworth, Allan J. Mosby's Medical Drug Reference. St. Louis, MO: Mosby, Inc, 1999.
Facts and Comparisons Staff. Drug Facts and Comparisons. 6th Edition. St. Louis, MO: Facts and Comparisons, 2002.
Novartis Staff. Exelon Package Insert. Basle, Switzerland: Novartis Pharma AG, 2001.
Kelly Karpa, RPh, Ph.D.