Dementia Medication Overview (cont.)
Treatment for Dementia
Acetylcholinesterase (AChE) inhibitors like tacrine (Cognex), donepezil (Aricept), galantamine/ galanthamine (Reminyl), and rivastigmine (Exelon) are approved by the United States Food and Drug Administration (FDA) for treatment of Alzheimer disease. They may be useful for other similar diseases causing dementia (for example, Parkinson disease). Unfortunately, improvement is neither dramatic nor permanent.
- How AChE inhibitors work: AChE inhibitors delay the breakdown of acetylcholine, a brain chemical needed for nerve cells to communicate. They may be useful for mild-to-moderate Alzheimer disease. Once AChE inhibitors are started, they should be continued indefinitely. Stopping the medication may cause an abrupt, and possibly severe, cognitive and behavioral decline that may not be resolved by restarting the AChE inhibitor. The cause for this potentially catastrophic decline with the discontinuation of the AChE inhibitors is not known.
- Who should not use these medications: People with the following conditions should not use AChE inhibitors:
- Allergy to AChE inhibitors
- Liver disease (avoid tacrine
- Use: AChE inhibitors come in tablets or capsules. The daily dose depends on the particular drug prescribed.
- Drug or food interactions: Certain drugs like cimetidine (Tagamet), ketoconazole (Nizoral), ritonavir (Norvir), paroxetine (Paxil), and erythromycin (E-Mycin) may increase AChE inhibitor toxicity. Certain drugs known as anticholinergics (antihistamines, bladder-control drugs) may decrease AChE inhibitors’ effectiveness. Other AChE inhibitors (often used during surgery) may increase effects.
- Side effects: AChE inhibitors may cause nausea, vomiting, diarrhea, muscle cramps, headaches, dizziness, fainting, appetite loss, and skin reddening. These effects can be lessened if the drugs are started at low doses then slowly increased until the desired maintenance dose is reached. Tacrine has a higher incidence of nausea, vomiting, and diarrhea, and persons taking tacrine must have their blood drawn on a regular basis to monitor for liver toxicity. Donepezil can cause abnormal dreams. Patients with heart rhythm disturbances (donepezil) or history of seizures (galantamine/galanthamine) are advised to use AChE inhibitors with caution.
Francisco Talavera, PharmD, PhD
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