Flashcards in Chapter 15 Antiparkinson Drugs Deck (21):
Parkinson’s Disease (PD)
-Chronic, progressive, degenerative disorder
-Affects dopamine-producing neurons in the brain
-Caused by an imbalance of two neurotransmitters
When do Symptoms occur in Parkinson's Disease?
-Symptoms occur when about 80% of the dopamine stored in the substantia nigra of the basal ganglia is depleted.
-Symptoms can be partially controlled as long as there are functioning nerve terminals that can take up dopamine.
Parkinson’s Disease Classic Symptoms Include:
absense of psychomotor activity resulting in masklike facial expression
Slowness of movement
"Cogwheel" rigidity, resistance to passive movement
Pill rolling: tremor of the thumb against the forefinger seen mostly at rest and less severe during voluntary activity; usually starts on one side then progresses to the other; is the presenting sign in 70% of cases; also seen as tremor of the hand and extremities
Unsteadiness that leads to danger of falling; leaning to one side, even when sitting
The “off–on phenomenon” that some patients with PD experience is best explained as the
variable response to levodopa, resulting in periods of good control and periods of poor control of PD symptoms
Difficulty in performing voluntary movements
Two Common types of Dyskinesia
Chorea and Dystonia
irregular, spasmodic, involuntary movements of the limbs or facial muscles
abnormal muscle tone leading to impaired or abnormal movements
Rasagiline (Azilect) and Selegiline (Eldepryl)
-Used as monotherapy or used as adjuncts with levodopa
Known drug allergy
Concurrent use with meperidine
-Levodopa is a precursor of dopamine.
-Blood–brain barrier does not allow exogenously supplied dopamine to enter but does allow levodopa to enter.
-Works by activating presynaptic dopamine receptors to stimulate the production of more dopamine
-Caution when used for patients with peripheral vascular disease
-Adverse reactions: GI upset, dyskinesias, sleep disturbances
-Drug interactions: erythromycin and adrenergic drugs
Ropinirole (Requip) and Rotigotine (Neupro)
Also used to treat a disorder known as restless legs syndrome, a nocturnal movement of the legs that disrupts sleep
-Anticholinergics block the effects of ACh
-Used to treat muscle tremors and muscle rigidity associated with PD
-These two symptoms are caused by excessive cholinergic activity.
-Does not relieve bradykinesia (extremely slow movements)
Ach is responsible for causing increased salivation, lacrimation (tearing of the eyes), urination, diarrhea, increased GI motility, and possibly emesis (vomiting)
-Anticholinergic drug used for PD and extrapyramidal symptoms from antipsychotic drugs
-Caution during hot weather or exercise because it may cause hyperthermia
-Adverse effects: tachycardia, confusion, disorientation, toxic psychosis, urinary retention, dry throat, constipation, nausea, and vomiting