Pharm110 Chp 31 Anti-Parkinsons agents

Question 1

Parkinsons disease

Answer 1

Neurological disorder characterized by

• Muscle tremors
• Muscle rigidity
• Lack of coordination
• Drooling
• Shuffling gait
• Postural changes

-Imbalance of dopamine and acetylcholine levels in brain
Levels of other neurological chemicals decrease
-GABA, Serotonin, Norepinephrine

Question 2

Classes of Anti-Parkinson agents

Answer 2

• Dopaminergic agents
• Anticholinergic agents
• Catechol-O-methyltransferase inhibitors (COMPT inhibitors)

Question 3

Levodopa

Answer 3

Dopaminergic agent
Action
-Most effective drug treatment
-Acts peripherally
-Rapidly converts to dopamine (by dopadecarboxylase)
-Symptoms subside or disappear
-Therapeutic intensity varies
-Therapy is dosage dependant

Adverse effects

• Nausea, vomiting, ortho hypotension, cardiac arrhythmias
• Psychiatric disturbances, intensification of narrow angle glaucoma
• off-on phenomenon
• Pyridoxine (vitamin B6) increases breakdown of levodopa

Question 4

Carbidopa/Levodopa (Sinemet)

Answer 4

Dopaminergic agent
Action
-Prevents break down of levodopa in peripheral circulation
-Improves neurological-skeletal muscle activity
-Combining agents reduces required Levodopa dose by 25%
-Given in Carbidopa 10mg / Levodopa 100mg dose
-Pyridoxine (vitamin B6) can be taken without concern

Question 5

Amantadine (Symmetrel)

Answer 5

Dopaminergic agent
Action
-Treats viral disorders such as influenza
-Acts as an anti-Parkinson agent; it exerts an additive effect on Levodopa (Increases CNS dopamine concentration)
-Releases dopamine from central neurons.
Adverse effects
-GI distress
-psychiatric disorders

Question 6

Trihexyphenidyl (Artane)
Benztropine mesylate (Cogentin)

Answer 6

Anticholinergic agent
Action
-Clients with minimal symptoms, combination with other AP drugs.
-Reduce excessive cholinergic brain activity
Adverse effects
-Dry mouth, urinary retention, blurred vision
-Caution use in pts. with narrow angle glaucoma

Question 7

Apomorphine (Apokyn)

Answer 7

Anticholinergic agent
Action
-Morphine like substance
-Rescue agent for frozen states of parkinsons
-No analgesic or addictive qualities
-Increases dopamine activity
-One of the most potent meds in treatment
-Like insulin, carefully measured amounts, IM admin.

Question 8

Tolcapone (Tasmar)

Answer 8

COMT Inhibitor (Catechol-O-Methyltransferase Inhibitors)
Action
-New class of PD agents
-Used as adjuncts to Levodopa/Carbidopa
-Treats clients with poor response to Levodopa
-Sustains dopaminergic levels
-Brain remains stimulated

Adverse effects

• Serious Hepatic injury
• Must check AST and ALT liver function every 2 weeks for first year and every 8 weeks thereafter.
• Pt observed for persistent nausea, fatigue, lethargy, anorexia, jaundice, dark urine, pruritus and RUQ tenderness.
• Most adverse effect liver failure

Question 9

Parkinsons pts

Answer 9

-High fall risk
-N/V or constipation
-Monitor pt weight
-On-off phenomenon
-Low drug dose and drug holidays instituted
-Complete withdrawal of levodopa 5-14 days
-Never abruptly stop meds
-S/S of neuroleptic malignant like syndrome, muscle rigidity, elevated body temp, mental changes
-Avoid B6 (Pyridoxine)
Notify Dr if, severe dry mouth, inability to chew or swallow, inability to urinate, sever drowsiness, rapid, irregular heartbeat