Pharmacotherapy of Cognitive and Motor Disorders

Question 1

NMDA (N-Methyl-D- Aspartate receptor)
Antagonists: Memantine

Answer 1

Use:
- Moderate to severe dementia in Alzheimer disease
Mechanisms of action:
- Antagonist action of CNS NMDA
receptors that may contribute to the symptoms of Alzheimer
disease
Desired effects:
- Improved mood, orientation, decreasing
confusion
Adverse effects:
- Dizziness, confusion, headache,
hypotension, vomiting, constipation, diarrhea, anemia, rash, back pain, fatigue

Question 2

Acetylcholinesterase
inhibitors:
Donepezil

Answer 2

Use:
- Mild to moderate Alzheimer disease
Mechanisms of action:
- increases acetylcholine levels in by inhibiting the enzyme acetylcholinesterase and slowing
the degradation of acetylcholine released in cholinergic neurons
(indirect-acting cholinergics)
Desired effects:
- slows the progression of decreased symptoms of Alzheimer disease.
Adverse effects:
- vomiting, diarrhea, darkened urine, insomnia, syncope, headache, irritability, headache, fatigue, chest pain, dehydration, and blurred vision

Question 3

Dopa decarboxylase inhibitors: carbidopa &
levodopa (Sinemet)

Answer 3

Use:
- Parkinson disease – it takes up to 6 months to reach max therapeutic effect
Mechanisms of action:
- Levodopa can enter the blood brain barrier
● As An immediate precursor to dopamine, levodopa crosses the blood-brain barrier (BBB) and is converted
to dopamine
● Dopamine cannot enter the blood-brain barrier, hence, why dopamine therapy is not used
Carbidopa and Dopamine cannot enter blood brain barrier
● Carbidopa functions to decrease the metabolism of levodopa to dopamine outside the CNS, which allows levodopa to be more available to enter the brain. So, Carbidopa “boosts” levodopa effectiveness
Desired effects:
- reduction of involuntary movements
Adverse effects:
- uncontrolled and purposeless movements such as extending the fingers and shrugging shoulders, involuntary movements, loss of appetite, nausea and vomiting, orthostatic hypotension

Question 4

Immunomodulator
Interferon
Beta-1b:
Betaseron

Answer 4

Indication: Ambulatory patients with relapsing
or remitting multiple sclerosis – given s.c.
Mechanisms of action: drug that’s not clearly
understood. Believed to act by suppressing
the activity of T-cells and reducing the
inflammatory actions of cytokines.
Desired effects: Decreased symptoms of
multiple sclerosis
Adverse effects: transient flu-like symptoms
(symptomatic therapy can be given to prevent
this), leukopenia, headache, insomnia,
asthenia, increased liver enzymes, rash,
peripheral edema, depression, suicidal
ideation and malaise