Chapter 32: Histamine Effect

Question 1

Diphenhydramine (what)

Answer 1

prototype first-generation antihistamine

Inhibit smooth muscle constriction in blood vessels and the respiratory and GI tracts, decreasing capillary permeability

Indications for diphenhydramine include hypersensitivity reactions (allergic rhinitis, conjunctivitis, dermatitis), motion sickness, insomnia, and parkinsonism

Question 2

Diphenhydramine (side effects)

Answer 2

e usually causes CNS depression (drowsiness, sedation) in therapeutic doses

may cause CNS stimulation (anxiety, agitation) with excessive doses, especially in children

substantial anticholinergic effects
(e.g., dry mouth, urinary retention, constipation, blurred vision)

Question 3

Diphenhydramine (contraindications)

Answer 3

Don’t consume alcohol while taking medication

Question 4

Diphenhydramine (assessment)

Answer 4

The nurse observes for a verbal statement of therapeutic effect (relief of symptoms), For decreased nasal congestion when given for hypersensitivity, for
decreased dizziness and nausea when taken for motion sickness, and for drowsiness or sleep when given for insomnia

assesses changes in level
of consciousness; dryness of mouth, nose, and throat; blurred vision; urinary retention; and constipation

Question 5

Diphenhydramine (Pt teaching)

Answer 5

Do not take more than one
antihistamine at a time. Avoid prolonged exposure to sunlight, and use sunscreens and protective clothing, causes sun sensitivity

Antihistamines may dry and thicken respiratory tract
secretions and make them more difficult to remove

Question 6

Hydroxyzine (what)

Answer 6

injection for nausea and vomiting or to provide sedation but are not usually the first drugs of choice for these indications

Vistaril - prototype

Question 7

Hydroxyzine (contraindications)

Answer 7

< 2 years of age, Reyes syndrome, hepatic disease

Question 8

Antihistamines (contraindications)

Answer 8

second-generation antihistamines are much safer than first-generation agents for older adults because they are less likely to impair consciousness, thinking, or
ability to perform activities of daily living