Chapter 30 Agents Used to Treat Parkinson’s Disease

2 Parkinson’s Disease A neurological disorder characterized by: Muscle tremors Muscle rigidity Lack of coordination Drooling Shuffling gait Postural changes

3 Parkinson’s Disease Slow onset – several months to years Approximately 1 million Americans affected Usually develops between the ages of Women and men equally affected Family history not a factor Progressive disease, if not treated causes death Cause is not completely understood

4 Parkinson’s Disease Imbalance of dopamine and acetylcholine levels in the brain Levels of other neurological chemical decrease: Gamma-aminobutyric acid (GABA) Serotonin Norepinephrine

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6 Classes of Anti-Parkinson Agents Dopaminergic agents Catechol-O-methyltransferase inhibitors Cholinesterase inhibitors Anticholinergic agents

Classes of Anti-Parkinson Agents Non-ergot dopamine agonists (direct- acting dopamine receptor agonists) May be classified as “dopaminergic” Indirect-acting dopamine receptor agonists (monoamine oxidase inhibitors, or MAOIs) Also can be classified as “dopaminergic” 7

8 Dopaminergic agents Levodopa prototype Most effective drug treatment Acts peripherally Rapidly converts to dopamine Symptoms subside or disappear

9 Levodopa Therapeutic effects Therapeutic intensity varies Dosage dependent Adverse effects Nausea and vomiting Orthostatic hypotension Cardiac arrhythmias

10 Carbidopa/Levodopa (Sinemet) Carbidopa prevents levodopa from being broken down in the peripheral circulation Improves neurological-skeletal muscle activity Combining these agents reduces the required Levodopa dose by 25% Carbidopa, 10 mg / Levodopa,100 mg dose

11 Amantadine (Symmetrel) Anticholinergic/dopaminergic in action Treats viral disorders such as influenza Acts as an anti-Parkinson agent; it exerts an additive effect on Levodopa Increases CNS dopamine concentration

Other dopaminergic anti-PD drugs Parlodel (bromocriptine mesylate) Ergot derivative; may allow reduced maintenance levodopa dosage Mirapex (pramipexole dihydrochloride) Nonergot; treats tremors, shaking, slow movements Also treats restless leg syndrome Can cause hypotension – teach slow position transition 12

Other dopaminergic anti-PD drugs Requip and RequipXL (ropinirole) Also treats RLS Lowers B/P Neupro (rotigotine) patch Nonergot; treats early-stage PD Sleep attacks 13

Other dopaminergic anti-PD drugs Zelapar (selegiline HCl) Indirect-acting dopamine receptor agonist /monoamine oxidase inhibitor Patch developed for antidepressant (Emsam) MAOIs – high risk of interaction with other medications Check for contraindications 14

15 Newest class of anti-Parkinson drug agents Treats clients with history of poor response to levodopa Sustains dopaminergic levels Brain remains stimulated Catechol-O-Methyltransferase Inhibitors

16 Catechol-O-Methyltransferase Inhibitors Adverse effects Liver failure Dyskinesia Orthostatic hypotension Dystonia Somnolence GI irritation Note interactions with other drugs

Catechol-O-Methyltransferase Inhibitors Adjuncts to levodopa Comtan (entacapone) Many interactions with other drugs Tasmar (tolcapone) Liver damage 17

Cholinesterase inhibitors Exelon (rivastigmine) – origin as Alzheimer’s drug (see Ch. 28) Apokyn (apomorphine HCl) SQ “rescue” drug for undermedicated, “frozen” state. Four- to eight-minute onset give with antiemetic r/t morphine; not analgesic, no dependency risk 18

19 Anticholinergic Agents Reduces excessive cholinergic brain activity Example: trihexyphenidyl (Artane) Used for clients with minimal symptoms Adjunct with other agents  Caution: narrow-angle glaucoma

Anticholinergic Agents Inhibit acetylcholine in PNS Cogentin (benztropine mesylate) Akineton (biperiden HCl) Kemadrin (procyclidine) Adjunct agents Use with minimal symptomsS 20

21 Adverse Effects of Anticholinergics Dry mouth Urinary retention Constipation

22 Nursing Considerations Patients on levadopa (not Sinemet) should not take vitamin B6 Educate patient on disease process, medication therapy goals, and adverse effects and what to do about them Assure adequate fluids Counsel patients to be careful when doing activities that require alertness

Nursing Considerations Assess for need for other supportive therapies such as physical, occupational, and speech High protein food may decrease absorption of levadopa Assess patients self care abilities on an ongoing basis Assess fall risk on an ongoing basis 23