Drugs for Movement disorders

Question 1

What two disease are associated with Dopamine loss or excess respectively

Answer 1

Parkinson

Schizophrenia

Question 2

Parkinson’s disease is a progressive disorder of VOLUNTARY movement characterized by what four primary manifestations

Answer 2

resting tremor

rigidity or increased resistance to passive stretching

bradykinesia

impaired postural reflexes

Question 3

The motor symptoms of Parkinson’s disease results from

Answer 3

the death of dopamine-generating cells in the substantia nigra and striatum

Question 4

Which Dopaminergic neurons are involved with Parkinson’s dx

Answer 4

D1 & D2 inhibitory neurons

Question 5

When would symptoms of Parkinsons emerge

Answer 5

when depletion exceeds 80-90%

Question 6

Name four stategies used to treat Parkinson’s disease

Answer 6

Dopamine replacement
Dopamine agonist
Antichlolinergic drugs
Protctive therapies

Question 7

What is the precursor to Dopamine

Answer 7

L-dopa

Question 8

What is the precursor to L-dopa

Answer 8

Tyrosine

Question 9

What enzyme is the rate-limiting step

Answer 9

Tyrosine hydroxylase

Question 10

What are the two enzymes that inactivate Dopamine, NE and Epi

Answer 10

MonoAmine Oxidase (MAO)
Catecholamine-O-MethylTransferase (COMT)

Question 11

What is the chemical obtained from dopamine metabolism

Answer 11

Homovanillic Acid (HMA)

Question 12

What is the chemical obtained from NE/EPi metabolism

Answer 12

VMA

Question 13

What are the two strategies used in dopamine replacement therapy

Answer 13

L-Dopa administration with carbidopa

• L-Dopa can cross BBB, but is also converted to Dopamine in the periphery (via L-aa decarboxylase), yielding increased CO and Hypotension.
• Carbidopa is given to combat the conversion of L-Dopa to Dopamine in periphery (via inhibiting L-aa decarboxylase)
• This allows for less L-dopa administration and less peripheral SE

Question 14

Should L-Dopa be taken on a full stomach

Answer 14

No b/c dietary aa competes with L-Dopa for absorption

• 90% of L-dopa is metabolized in the small intestines.
• 9% in other peripheral sites
• 1% enters the brain

Question 15

What is the “on-off” phenomenon associated with dopamine replacement therapy

Answer 15

“on” = adeqate dopamine> normal movement

“off” = dopamine levels too low > tremors, cramps, and immobility (parkinsonism)

*This is seen in 1/2 of all patient’s treated for 5 years with levodopa/ carbidopa

Question 16

Another strategy to tx Parkinson’s disease is Dopamine agonist therapy, what drug is used to accomplish this

Answer 16

Bromocriptine

Question 17

Another strategy to tx Parkinson’s disease is Anticholinergic drugs, what drug is used to accomplish this

Answer 17

Benztropine (Cogentin)

Question 18

Name a drug used as a protective strategy for Parkinson’s disease

Answer 18

Selegiline

Question 19

What is the MOA of selegiline

Answer 19

MAO B inhibitor

Question 20

What movement disorder is opposite to Parkinson’s disease

Answer 20

Huntington’s disease or Huntington’s Chorea

Question 21

Huntington’s disease is characterized by

Answer 21

Too much dopamine release in degenerated caudate and putamen (striatum)

Question 22

What is the treatment strategy for Huntington’s disease

Answer 22

Symptom control

Question 23

What are some common symptoms that drugs target in patient’s with Huntington’s chorea

Answer 23

Antipsychotics for hallucinations and delusions

Antidepressants

Botulinum toxin for dystonia (crithing) and jaw clenching