LEHNE’S PHARMACOTHERAPEUTICS FOR ADVANCED PRACTICE NURSES AND PHYSICIAN ASSISTANTS TEST BANK WITH CORRECT ANSWERS A nurse is teaching a group of students about how CNS drugs are developed. Which statement by a student indicates a need for further teaching? a. "Central nervous system drug development relies on observations of their effects on human behavior." b. "Studies of new central nervous system drugs in healthy subjects can produce paradoxical effects." c. "Our knowledge of the neurochemical and physiologic changes that underlie mental illness is incomplete." d. "These drugs are developed based on scientific knowledge of CNS transmitters and receptors." - -answer-ANS: D The deficiencies in knowledge about how CNS transmitters and receptors work make systematic development of CNS drugs difficult. Testing in healthy subjects often leads either to no effect or to paradoxical effects. Medical knowledge of the neurochemical and physiologic changes underlying mental illness is incomplete. The development of CNS drugs depends less on knowledge of how the CNS functions and how these drugs affect that process and more on how administering one of these agents leads to changes in behavior. A nurse is teaching a group of nursing students how the CNS adapts to psychotherapeutic medications. Which statement by a nursing student indicates a need for further teaching? a. "Adaptation can lead to tolerance of these drugs with prolonged use." b. "Adaptation helps explain how physical dependence occurs." c. "Adaptation often must occur before therapeutic effects develop." d. "Adaptation results in an increased sensitivity to side effects over time." - - answer-ANS: D With adaptation of the central nervous system to prolonged exposure to CNS drugs, many adverse effects diminish and therapeutic effects remain. Adaptation helps explain how tolerance and physical dependence occur, as the brain adapts to the presence of the drug. Therapeutic effects can take several weeks to manifest, because they appear to work by initiating adaptive changes in the brain. A psychiatric nurse is teaching a patient about an antidepressant medication. The nurse tells the patient that therapeutic effects may not occur for several weeks. The nurse understands that this is likely the result of: a. changes in the brain as a result of prolonged drug exposure. b. direct actions of the drug on specific synaptic functions in the brain. c. slowed drug absorption across the blood-brain barrier. d. tolerance to exposure to the drug over time. - -answer-ANS: A It is thought that beneficial responses to central nervous system (CNS) drugs are delayed because they result from adaptive changes as the CNS modifies itself in response to prolonged drug exposure, and that the responses are not the result of the direct effects of the drugs on synaptic functions. The blood-brain barrier prevents protein-bound and highly ionized drugs from crossing into the CNS, but it does not slow the effects of drugs that can cross the barrier. Tolerance is a decreased response to a drug after prolonged use. An infant who receives a drug that does not produce CNS side effects in adults exhibits drowsiness and sedation. The nurse understands that this is because of differences in which physiologic system in infants and adults? a. Blood-brain barrier b. First-pass effect c. Gastrointestinal absorption d. Renal filtration - -answer-ANS: A