Alzheimers Disease

Alzheimers Disease

Alzheimer’s disease is the most common cause of dementia and is a growing public health concern. The cause of dementia is thought to be a combination of genetic and lifestyle factors, although the disease is still not completely understood. The disease is characterized by the buildup of amyloid plaques and neurofibrillary tangles in the brain, causing neurodegeneration with synaptic and neuronal loss leading to macroscopic atrophy (Lane et al., 2018). The disease has an insidious course and presents with increasing memory loss and cognitive impairment, with death normally occurring approximately 8.5 years after onset of symptoms (Lane et al., 2018). Currently treatment is supportive, that is medications offer symptoms management but there is no cure (Briggs et al., 2016).   Medication therapy for Alzheimer’s Disease generally involves acetylcholinesterase inhibitors such as rivastigmine or donepezil, or Memantine which is classified as a NMDA receptor blocker (Woo & Robinson, 2020). Other medications may be used off label to treat symptoms of dementia, especially if behavioral symptoms are present, but currently there are only 5 FDA approved medications authorized for Alzheimer’s dementia (Briggs et al., 2016). Acetylcholinesterase inhibitors prevent the degradation of acetylcholine by acetylcholinesterase, therefor increasing the activity of acetylcholine at cholinergic junctions (Woo & Robinson, 2020). Alzheimer’s disease involves a deficiency of the enzyme responsible for acetylcholine synthesis, therefore this class can help overcome the deficiency of the neurotransmitter (Woo & Robinson, 2020). All meds in this class tend to increase gastric acid secretions, and patients should be monitored for occult GI bleeding (Woo & Robinson, 2020). They also have the potential for seizures and should be used cautiously in patients with bronchospastic disorders, peptic ulcer disease, cardiovascular disorders, and hyperthyroidism (Woo & Robinson, 2020). Common side effects include muscle weakness, cramps, and spasms as well as nausea, diarrhea, headaches, and insomnia, and dizziness (Woo & Robinson, 2020). Donepezil is the most commonly prescribed acetylcholinesterase inhibitor for the treatment of Alzheimer’s disease, education for it includes if you miss a dose to skip it and take it as scheduled the next day. Routine lab monitoring of blood chemistries and hematology are also advised. Dosing should be started at 5mg daily at bedtime for 4-6 weeks, and then increased to 10 mg if tolerable because it is more effective in the treatment of Alzheimer’s disease at this dose (Woo & Robinson, 2020). Rivastigmine requires twice daily dosing, patients should be started on 1.5mg BID with food and increased by 1.5mg at 2-week intervals to reach an ultimate dose of 3-6 mg BID for maximum effectiveness (Woo & Robinson, 2020). This medication is available in a patch for patient’s who have difficulty swallowing. Baseline liver function tests are recommended, and education if using the patch should include proper application and site rotation (Woo & Robinson, 2020). Memantine has similar adverse drug reactions to acetylcholinesterase inhibitors, it can be taken without regards to meals. It requires not dose adjustment for hepatic impairment, however renal impairment may cause higher levels in the blood (Woo & Robinson, 2020).