CNS -Antiparkinsonian Drugs

1. CNS -Antiparkinsonian Drugs • Discuss the signs and symptoms exhibited by a patient with Parkinson’s Disease • Describe the actions and intended effects of medications used to treat the signs and symptoms of Parkinson’s Disease

2. CNS Antiparkinsonian Drugs • Parkinson’s Disease: • Disease of the basal ganglia & related neuronal groups + neurotransmitter deficiencies • “shaking palsy” • Bradykinesia – slowing down in the initiation & execution of movement • Rigidity – increased muscle tone • Tremor at rest • Impaired postural reflexes

4. CNS Antiparkinsonian Drugs • Degeneration of dopamine-producing neurons in the substantia nigra of the midbrain • Disrupts the balance of: • dopamine (DA) – neurotransmitter for normal functioning of the extrapyramidal motor system (control of posture, support, and voluntary motion) • Acetylcholine (Ach) • and the basal ganglia • Symptoms do not occur until 80% of the neurons in the substantia nigra are lost

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6. CNS Antiparkinsonian Drugs • Five Stages • Flexion of affected arm - tremor / leaning toward unaffected side • Slow shuffling gate • Increased difficulty walking – looks for support to prevent falls • Further progression of weakness – assistance with ambulation • Profound disability – may be confined to wheelchair

7. CNS Antiparkinsonian Drugs • Tremor • First sign • Affects handwriting – trailing off at ends of words • More prominent at rest • Aggravated by emotional stress or increased concentration • “Pill rolling” – rotary motion of thumb and forefinger • NOT essential tremor – intentional

8. CNS Antiparkinsonian Drugs • Rigidity • Increased resistance to passive motion when limbs are moved through their range of motion • “Cogwheel rigidity” -- Jerky quality – intermittent catches of movement • Caused by sustained muscle contraction • Muscle soreness; feeling tired & achy • Slowness of movement due to inhibition of alternating muscle group contraction & relaxation in opposing muscle groups

9. CNS Antiparkinsonian Drugs • Bradykinesia • Loss of automatic movements: • Blinking of eyes, swinging of arms while walking, swallowing of saliva, self-expression with facial and hand movements, lack of spontaneous activity, lack of postural adjustment • Results in: stooped posture, masked face, drooling of saliva, shuffling gait (festination); difficulty initiating movement

11. CNS Antiparkinsonian Drugs • Drug Therapy • Correcting the imbalance of neurotransmitters within the CNS • Dopaminergic – enhance release or supply of dopamine (DA) • Anticholinergic – antagonize or block the effects of overactive cholinergic neurons in the striatum • Monoamine Oxidase Inhibitor • Decreases MAO (the degradative enzyme for DA) • Results: DA levels are increased • Catechol-O-Methyl Transferase (COMT) Inhibitor • Betablocker • Antihistamine

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16. CNS Antiparkinsonian Drugs • Anticholinergic Drugs: decrease the activity of Ach • Benztropine (Cogentin) • Antihistamines – decreases rigidity • Benadryl • Betablockers – decreases rigidity • Inderal • Monoamine oxidase inhibitor (MAOI): • Selegiline (Eldepryl ) • Catechol-O-Methyl Transferase (COMT) Inhibitor • Entacapone (Comtan)

17. CNS Antiparkinsonian Drugs • Drug Therapy • Sinemet early in disease becomes ineffective • Early: DA receptor agonist -- directly stimulate DA receptors • Parlodel, Requip, Mirapex • Moderate to severe symptoms: • Sinemet is added to therapy

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21. CNS -- Antiparkinsonian DrugsNursing Process • Assessment • Head-to-toe • Neuro • GI/GU • Ability to swallow • Psychological and emotional coping • Parkinson progression • Medication History • Length of time on medications • Changes in medications and effects • Safety • Ability to perform ADLs independently

22. CNS -- Antiparkinsonian DrugsNursing Process • Nursing Actions • Exact timing of medication – cannot be administered late • Oral doses given with food • Avoid foods in Vit B6 – reverse effects of levodopa • Wheat germ, whole grain cereals, muscle & glandular meats (particularly liver), legumes, green leafy vegetables, bananas • Force fluids >2,000 mL/day • High roughage, high fiber diet

23. CNS -- Antiparkinsonian Drugs Patient Education • “Wearing off” – “On-Off” phenomenon – gradual worsening of symptoms as medication begins to lose effectiveness, despite maximal doses • “Drug Holiday” when levodopa no longer working effectively (usually 10-day period of hospitalization) • Community resources to assist patient and family • Safety • Effect on blood pressure – • Hypotension • Hypertensive crisis of MAOI accidentally taken • “Sleep attacks” – newer dopamine agonists (pramipexole & ropinirole) • GI: Constipation – high fiber, high roughage, increased fluids • GU: urine color changes – brownish-orange (entacapone)

24. CNS – Antiparkinsonian DrugsMonitoring Therapeutic Effects • Therapeutic Response: • Improved sense of well being • Ability to perform ADLs • Ability to concentrate and think clearly • Less intense parkinsonian manifestations • Observe for Adverse Effects: • Confusion, anxiety, irritability, depression, paranoia, headache, weakness, lethargy, nausea, vomiting, anorexia, palpitations, postural hypotension, tachycardia, dry mouth, constipation, urinary retention, blurred vision, dark urine, difficulty swallowing, and nightmares

25. CNS – Antiparkinsonian Drugs • Carbidopa in Parkinson’s disease is to be used: • a. As successful monotherapy. • b. In conjunction with levodopa to block peripheral conversion to dopamine. • c. To decrease the incidence of gastrointestinal side effects associated with levodopa. • d. 2 and 3

26. CNS – Antiparksonian Drugs • Discuss the normal course of progression of Parkinson’s disease. Include the rationale for drug therapy to alleviate the symptoms.