Huntington's and Alzheimer's Disease Flashcards
1
Q
Tetrabenazine
A
- VMAT inhibitor.
- Promotes the early metabolic degradation of monoamines, in particular dopamine.
- Used for symptomatic treatment of hyperkinetic movement disorder/Huntington’s.
2
Q
Donepezil
A
- Reversible AChE inhibitor.
- Prevents breakdown of AChE, thus more ACh available in the brain.
- Combats the loss of ACh due to cholinergic neuron death.
- Indicated in symptomatic treatment of mild to moderate Alzheimer’s. Small improvements in cognition and function occur within 12-24 weeks, benefits last for 2 years.
- Adverse effects include cholinergic effects.
Metabolized by CYP.
3
Q
Rivastigmine
A
- AChE inhibitor.
- Administered orally or via a transdermal patch.
- Cholinergic side effects (as there is more ACh available in the synapse).
4
Q
Galantamine
A
- Reversible AChE inhibitor primarily in the CNS. Also stimulates nicotinic receptors.
- Symptomatic treatment of mild to moderate Alzheimer’s. Benefits last for more than 1 year.
5
Q
Memantine
A
- NMDA receptor antagonist.
- Inhibits over stimulation of glutamate receptors.
- Requires dose titration over a month to minimize ADRs of agitation, hallucination and headache. Not suitable for those with renal impairment.
6
Q
What is Huntington’s Disease?
A
- An inherited adult onset neurologic disease. Due to a single defect on chromosome 4.
- Always fatal, with death at 50-55 years.
7
Q
How is Huntington’s characterized?
A
- Shuffling gait, stooped posture, resting tremor, speech impediment, movement difficulties, and eventual slowing of mental processes and dementia.
8
Q
What is the pathophysiology of Huntington’s?
A
- Thought to occur because of excessive dopaminergic activity and diminished GABA functions in the basal ganglia.
9
Q
How does Parkinson’s and Huntington’s differ?
A
- Parkinson’s: decreased dopamine and decreased suppression of basal ganglia means increased GABA. Decrease in movements.
- Huntington’s: Decreased GABA means an increase in movements.
10
Q
What is Alzheimer’s Disease?
A
- Progressive impairment of memory (short-term initially) and cognitive function (vegetive state). Usually fatal 6-12 years after onset. Increased incidence with increased age.
11
Q
What is the neurotransmitter basis for current Alzheimer’s drug treatment?
A
- ACh and glutamate are 2 neurotransmitters known to be important in learning and memory.
- ACh involvement - cholinergic neurons lost in AD, thus treatment is to increase available ACh
- Glutamate involvement - excessive or erratic stimulation impair learning and can cause neuronal toxicity. Treatment involves normalizing glutamate neurotransmission.
