L4 DD

Question 1

Drugs for Parkinsonism

Answer 1

Dopamine Agonists ( L- dopa)
MAO inhibitors
COMT inhibitor
Anti-muscarinic drugs
Amantadine & apomorphine

Question 2

Levodopa (L-dopa):

Answer 2

-Given with carbidopa/or bensarazide
-Can cross BBB
-Converted to dopamine in brain by dopa-decarboxylase enzyme
- restores dopamine in basal ganglia
-oral

Question 3

Uses of l-dopa?

Answer 3

• Levodopa & carbidopa usually given as first line
• Initially, improvement in tremors, rigidity & dyskinesia
• Gradually, other symptoms improve.

Question 4

Adverse effects of L- dopa

Answer 4

1-Mydriasis and precipitation of glaucoma
2- sleep loss& psychosis, hallucinations
3- nausea & vomiting اول الاعراض
4-On off phenomenon بسبب الهاف لايف القصير
5-CVS: Cardiac arrhythmias, postural hypotension
6-Dyskinesias

Question 5

Drug interactions with L- dopa

Answer 5

-Vit B6 causes its peripheral break down (inc. DC )
- use with MAO inhibitor like phenelzine cause hypertensive crises( increase in catecholamine)

-Antipsychotic drugs specially the typical one should not be given because will block D2 receptors in substancia nigra & will cause extrapyramidal side effects

Question 6

Drugs
inhibit peripheral breakdown of levo dopa in liver & other tissues & ↑ its availability in brain?

Answer 6

Carbidopa & Benzsarazide
(DOPA decrboxylase inhibitors in the periphery )

Question 7

Effects of Combination of Levodopa with carbidopa or bensarazide ?

Answer 7

-Dec.periphral conversion to dopamine
-Inc. amount of l-dopa entering brain (1-2% to 10 %),
­-inc.efficacy
-Dec. its side effects: nausea, vomiting & cardiac complications
-Dec. ‘on off’ phenomenon
-Reduces the dose of l-dopa to 1/4

Question 8

COMT - inhibitors Tolcapone & entacapone

Answer 8

• Tolcapone block both peripheral & cental metabolism of levodopa and is longer acting
• Entacapone blocks only peripheral metab. & is short acting

importance?
- ↓ 3-OMD formation so will increase­ dopamine in brain
(3-OMD competes with levodopa for transport across BBB)

• Reduce ‘off’ phenomenon & given with l-dopa & carbidopa

Question 9

• Selegiline & Rosagiline are

Answer 9

Selective MAO B inhibitors (less interaction with cheese)
فقط in brain 👍

MAO A inhibitor ( led to interaction with cheese )
ممنوع لانه يشتغل باماكن ثانيه بالجسم

وعندهم:
Neuro-protective action: ↓ formation of oxidant (H2O2)
reduces ‘off’ phenomenon
Rosagiline is more potent

Question 10

Importance of MAO b inhibitors
نفس الكارد اللي قبله

Answer 10

Rosagiline is more potent than selegiline
Increase ­ amount of dopamine in the neurons & synapses
Neuro-protective action: ↓ formation of oxidant (H2O2)
Combination with levodopa reduces ‘off’ phenomenon •

Question 11

Dopamine Receptor Agonists

Answer 11

Bromocryptine & pergolide (Ergot derivatives)
Pramipexole & ropinirol (Non-ergots)

• they are Long acting - sustained stimulation of D2 receptors
Can be used early, intermediate & late stages of illness

Question 12

• uses of Bromocryptine

Answer 12

• Parkinsonism
• Hyperprolactenemia

Question 13

• Adverse effects of Dopamine Receptor Agonists ( bromocryptine) ?

Answer 13

• can cause digital vasospasm, pleural, peritoneal & retro-bulbar fibrosis

Question 14

Amantadine MOA?

Answer 14

­ release &/or dec. reuptake of dopamine
Most effective in patients who have more dyskinesia or rigidity than tremors

Question 15

• Can be used in early stages of PD
• Also has antiviral effect (against Influenza A virus)
• May cause psychosis & edema.

Answer 15

Amantadine

Question 16

• Apomorphine:

Answer 16

• Short & rapid acting dopamine agonist, given SC
• Used as rescue drug in akinetic emergencies in PD
• Always use with domperidone to control vomiting.

Question 17

Anti-muscarinic drugs:

Answer 17

Benzhexol,Benztropine, procyclidine, phencyclidine,
trihexyphenidyl (Pacitane)

Question 18

Anti-muscarinic drugs uses?

Answer 18

• Most effective in patients who have more tremors than rigidity or hypokinesia.
• control salivation
• Used when some drugs induce Parkinsonism

Question 19

• Used commonly for drug induced Parkinsonism
e.g. Metoclopramide, haloperidol & phenothiazines(D2 blockes)?

Answer 19

Anti-muscarinic drugs. As trihexyphenidyl

Question 20

• Adverse effects of anti-muscarinic drugs?

Answer 20

• Dry mouth, constipation, mydriasis, blurred vision, tachycardia, palpitation, urine retention

-Contraindications:
• Prostatic Hypertrophy & glaucoma, urinary retention

Question 21

Drugs for Alzheimer’s Disease ( due to dec. ACH )

Answer 21

1-Anti-Cholinesterases (centrally acting)
• Donepezil Galantamine & Rivastigmine

-Cholinergic side effects:
insomnia, anorexia, nausea,vomiting, and diarrhea •

2-Glutamate antagonists
• Memantine is a N-methyl-D-aspertate(NMDA)-receptor antagonist that affects glutamate transmission

3-Anti-psychotics/or anti-depressants
• For behaviour problems

Question 22

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