The Exelon Patch and Rivastigmine
The Exelon patch is a means of dosing a patient with mild to moderate Alzheimer's disease with rivastigmine. The patch allows the rivastigmine to enter the bloodstream in a steady level for 24 hours. Rivastigmine is a cholinesterase inhibitor which has gastrointestinal side effects in some patients who take the oral capsule, so the patch allows a patient to receive the drug in a steady delivery of up to 9.5 mg. every 24 hours.
The article about Novartis' Exelon patch, dated 09 Jul 2007, approaches the product in a positive way, stating that over 70% of patients preferred using the patch for receiving rivastigmine to the oral capsule form of the drug. The article reminds one that by 2030 the number of people with Alzheimer's disease is expected to be 7.7 million and that convenience of delivery of this drug will assist caregivers and will interfere less with a patient's daily life, while assuring an accurate treatment schedule.
However, findings by clinical groups who have studied the drug over the course of many years have found that rivastigmine is not recommended in the treatment of patients with mild to moderately severe Alzheimer's disease.
1. What is the difference between using this med. For Alzheimer's vs. Parkinson's dementia?
Parkinson's disease is treated in 70-80% of patients with Carbidopa/Levodopa (Sinemet®). "Levodopa is a substance that is converted into dopamine by an enzyme in the brain. It is then released by brain cells and activates dopamine receptors allowing for normal function of the movement control centers of the brain" (Medications, p. 1). Rivastigmine is also prescribed for Parkinson's disease for those who have additional dementia, as it increases mental functioning.
2. How are these two dementias physiologically different or alike?
Parkinson's disease affects the substantia nigra and causes it to deteriorate and die. It is a progressive, chronic movement disorder whose primary symptoms are tremors, poor balance, slow movement (bradykinesia), rigidity and difficulty walking ("Parkinsonian gait").
Alzheimer's disease is also progressive, but it is not confined to the movement control center of the brain. It destroys brain cells in the memory, thinking and behavior areas of the brain, rather than only the movement center. It is fatal and is the seventh leading cause of death in the United States today, whereas Parkinson's disease is not listed in the leading causes of death (What, p. 1).
3. What is this drug called rivastigmine? How is it used? What is the history?
Rivastigmine is similar to the drugs neostigmine (Prostigmin), physostigmine (Antilirium, Isopto Eserine), and pyridostigmine (Mestinon, Regonol), which treat the brain and nervous system. It is also sometimes used to treat Lewy body dementia. It comes in capsule, solution (syringe) and patch form and is usually taken twice a day in accurate doses, as too much may cause gastrointestinal disorders (Rivastigmine, p. 1).
Rivastigmine was evaluated first in 2001, and was again analyzed in 2005 by the National Institute for Clinical Excellence who found that "Donepezil, rivastigmine and galantimine are not recommended for use for the treatment of mild to moderate Alzheimer's disease." The 2001 Committee had found that taking rivastigmine and the other related drugs could result in delay for requirements for full time care, but the 2005 analysis disputed this, finding that "Data acquired since 2001 show that improvements in cognition (memory)... could be less than originally observed and was certainly no more" (NHS, 2005, p. 2).
In other words, the study found rivastigmine had no effect on improving memory, it did not delay full time care and did not improve the quality of life of patients with Alzheimer's.
The latest appraisal in 2007 echoes the earlier one in that these three drugs (Donepezil, rivastigmine and galantamine are not recommended in the treatment of people with mild to moderately severe Alzheimer's disease (NHS, 2007, p. 1).
Currently, clinical trials are being formed, sponsored by the U.S. National Library of Medicine, the U.S. National Institutes of Health and the U.S.Department of Health and Human Services to determine if the drug is affective. The claims by the drug companies necessitate this ongoing study,…