NURS 111 Parkinson's Disease Final Exam Latest Questions with Answers

Parkinson's Disease Ray A. Hargrove­Huttel, PhD, RN Medications Leo was prescribed the antiparkinsonian medication carbidopa­levodopa (Sinemet) shortly after being diagnosed with Parkinson's disease. Before starting the medication, the nurse in the healthcare provider's office explained the action of Sinemet as part of medication teaching. 1. Which statement explains the mechanism of action of Sinemet in the treatment of Parkinson's disease? A) Sinemet counteracts the neurotransmitter acetylcholine and restores the natural balance of neurotransmitters in the CNS. INCORRECT This is not the mechanism of action for Sinemet. Anticholinergics such as benztropine (Cogentin) are used to block acetylcholine and restore neurotransmitter balance. B) Sinemet inhibits dopamine breakdown, leading to increased amounts of dopamine available in the CNS. INCORRECT This is not the mechanism of action for Sinemet. Monoamine oxidase (MAO) inhibitors, such as selegiline (Eldepryl, Carbex), inhibit dopamine degradation (breakdown), thus making more dopamine available in the CNS. C) Sinemet causes a release of dopamine from neuronal storage sites and blocks re­uptake of dopamine. INCORRECT This is not the mechanism of action for Sinemet. Indirect acting dopaminergics, such as amantadine (Symmetrel), cause the release of already present endogenous dopamine and prevent dopamine reuptake. D) Sinemet is converted to dopamine and provides an exogenous form of dopamine replacement. CORRECT Sinemet, a combination of levodopa and carbidopa, provides an exogenous source of dopamine to the CNS. Levodopa crosses the blood­brain barrier and is converted to dopamine. Carbidopa does not cross the blood­brain barrier. Its role is to prevent the breakdown of levodopa in the periphery, allowing more levodopa to cross the blood­brain barrier. This in turn allows lower doses of levodopa to be used and reduces the risk of side effects such as nausea and vomiting