NURSING PNN101Chapter 09: Drug Therapy for Central Nervous System Problems Visovsky: Introduction to Clinical Pharmacology, 9th Edition

1. Which neurotransmitter has an inhibitory action within the central nervous system? a. Epinephrine b. Acetylcholine c. Norepinephrine d. Gamma-aminobutyric acid ANS: D Neurotransmitters can be excitatory or inhibitory. Excitatory neurotransmitters include acetylcholine (Ach), epinephrine, and norepinephrine. Inhibitory neurotransmitters include dopamine, some types of serotonin, and GABA (gamma-aminobutyric acid). DIF: Cognitive Level: Knowing REF: p. 159 2. How does the drug tolcapone relieve the symptoms of Parkinson disease? a. Acts as a dopamine agonist, replacing the activity of dopamine b. Forces the substantia nigra to increase the production and release of natural dopamine c. Suppresses the activity of an enzyme that normally breaks down naturally occurring dopamine d. Increases the number of dopamine receptors sites throughout the central nervous system, thus increasing the effectiveness of dopamine and dopamine agonists ANS: C Catechol-O-methyltransferase (COMT) is an enzyme that breaks down (metabolizes) naturally occurring catecholamine-based neurotransmitters, including dopamine. It also breaks down dopamine agonist drugs. Catechol-O-methyltransferase (COMT) inhibitors are drugs that suppress the activity of the COMT enzyme so both naturally occurring dopamine and dopamine agonist drugs remain active in the body longer, helping to restore the acetylcholine–dopamine balance in the brain. Entacapone (Comtan) and tolcapone (Tasmar) are two COMT inhibitors that are used currently for PD. DIF: Cognitive Level: Understanding REF: p. 162 3. Why are carbidopa and levodopa usually given together? a. Carbidopa is a dopamine agonist and levodopa is a dopamine antagonist. b. Levodopa is a dopamine agonist and carbidopa is a dopamine antagonist. c. Carbidopa enhances the action of levodopa, and less drug is needed. d. Levodopa reverses or prevents the side effects of carbidopa.