Rivastigmine Tartrate

Source: National Institutes of Health (NIH).

Rivastigmine tartrate (marketed as Exelon) is a prescription drug used to treat dementia that occurs in Alzheimer disease and Parkinson disease. Dementia is a decline in brain funtion beyond that which is expected in normal aging. This is manifested by symptoms such as memory loss, difficulty with activities of daily living and difficulty controlling the emotions. Rivastigmine tartare belongs to a family of drugs called cholinesterase inhibitors. Other members of this family include physostigmine, neostigmine, and pyridostigmine.

Uses

Rivastigmine tartare is specifically indicated for the treatment of mild to moderate dementia in Alzheimer's and Parkinson's disease.

How Rivastigmine Tartrate is Taken

Capsules

The starting dose of rivastigmine tartare is 1.5 mg twice daily.

If this starting dose is well tolerated, after a minimum of 2 weeks, the dose may be increased to 3 mg twice daily. Subsequent increases to 4.5 mg twice daily and 6 mg twice daily should be attempted after a minimum of 2 weeks at the previous dose.

Doses are generally taken in the morning and evening.

Oral solution

The dosing for the oral solution is the same as that of the capsule. A dose of rivastigmine solution may be swallowed directly from the syringe or first mixed with a small glass of water, cold fruit juice or soda.

Patch

Treatment is started with the 5 cm^2 rivastigmine patch.

After a minimum of four weeks of effective treatment, this dose is increased to the 10 cm^2 patch, which is the recommended effective dose.

How Rivastigmine Tartrate Works

Dementia in Alzheimer and Parkinson diseased involve cholinergic nerve pathways that project from the basal forebrain to the cerebral cortex and hippocampus in the brain. These pathways are thought to be intricately involved in memory, attention, learning, and other cognitive processes.

While the precise mechanism of rivastigmine's action is not completely understood, it is believed to work by improving cholinergic function in the aforementioned pathways. This is accomplished by increasing the levels of the neurotransmitter acetylcholine in the spaces between brain cells (synapses). This is achieved through inhibiting the enzyme that breaks down acetylcholine (cholinesterase).

How the Body Affects Rivastigmine Tartrate

After a 6-mg oral dose of rivastigmine tartare, anticholinesterase activity is present in the cerebrospinal fluid (CSF), the fluid bathing the brain and spinal cord, for approximately 10 hours.

Rivastigmine is primarily metabolized to a metabolite called NAP226-90. This metabolite is then rapidly eliminated through the urine via the kidneys.

Benefits

Acetylcholinesterase inhibitors have been shown to be effective in the treatment of dementia in Alzheimer's disease. Rivastigmine has less liver toxicity and fewer drug interaction than earlier medicines in this class, thus making it a favorable treatment alternative. ^[1]

Rivastigmine tartare was also shown as beneficial in the treatment the dementia associated with Parkinson disease. ^[2]

Side Effects

The most common side effects attributable to rivastigmine tartare are:

• Nausea
• Vomiting
• Anorexia (loss of appetite)
• Dyspepsia (indigestion, pain and fullness in the upper abdomen)
• Asthenia (weakness or lack of strength)

Risks

Interactions

An additive effect may be expected when cholinesterase inhibitors like rivastigmine are given concurrently with succinylcholine, similar neuromuscular blocking agents or cholinergic agonists such as bethanechol.

Precautions

Because of the risk of gastrointestinal side effects, it is recommended that the dose of rivastigmine tartare always be started as low as possible (1.5 mg) and titrated upward slowly. If treatment is interrupted for more than a few days, the medicine should be re-started at the lowest possible dose.

History

Rivastigmine tartare is marketed by Novartis as Exelon. FDA approval was granted on June 27, 2006.

Research

Recent Discoveries

Recently completed clinical trials (results pending) include:

• The safety and efficacy of memantine hydrochloride (another medication used to treat dementia in Alzheimer disease) and rivastigmine tartrate, when both drugs are taken together.
• Several studies looking at the safety and efficacy of the rivastigmine patch and comparing the rivastigmine patch with other medicines currently used in the treatment of Alzheimer disease.
• The efficacy of rivastigmine in the treatment of cognitive problems associated with traumatic brain injury and the cognitive problems associated with vascular disease.
• To determine whether there is a change in the length of time between the onset of mild cognitive impairment and a clinical diagnosis of Alzheimer disease in patients taking rivastigmine tartrate.
• Whether or not rivastigmine tartrate will be helpful in preventing postoperative delirium in patients undergoing cardiac surgery.

Clinical Trials

A list of ongoing clinical trials is available at: Rivastigmine Tartare Clinical Trials

References

1. ↑ Birks J, Iakovidou V, Tsolaki M. Rivastigmine for Alzheimer's disease. Cochrane Database Sys Rev. 2000;(2):CD001191. Abstract
2. ↑ Emre M, Aarsland D, Albanese A. Rivastigmine for dementia associated with Parkinson's disease. N Eng J Med. 2004 Dec 9;351(24):2509-18. Abstract | PDF

External Links

FDA: Patient Information Sheet

Alzheimer's Association

Alzheimer's Disease Education and Referral (ADEAR) Center Web site

National Parkinson Foundation