Questions and Answers with Detailed
Rationales | 100% Accurate
• What are H1 antagonists used to treat in allergic disorders? -✓✓Mild allergic
reactions, such as allergic rhinitis and urticaria.
• What are the anticholinergic adverse effects of H1 antagonists? -✓✓Dry mouth
and urinary retention
• What depressive effects can H1 antagonists cause? -✓✓Sedation and impaired
ability, more common in FGA due to crossing the BBB
• What behavioral adverse effects are associated with H1 antagonists? -
✓✓Confusion and apathy
• What stimulatory effects can H1 antagonists have? -✓✓Muscle spasm and
appetite stimulation
• What gastrointestinal adverse effects can occur with H1 antagonists? -
✓✓Discomfort
• What can happen at high doses of H1 antagonists? -✓✓CNS seizures and
hallucinations
• In which populations are H1 antagonists contraindicated? -✓✓Newborns,
children under the age of 2, and women who are breastfeeding.
,• What conditions contraindicate the use of H1 antagonists? -✓✓Narrow-angle
glaucoma, prostatic hypertrophy, and acute exacerbation of asthma.
• What is the effect of H1 antagonists on allergic rhinitis? -✓✓Reduces sneezing,
nasal discharge, and irritation of the eyes, nose, and throat.
• What is the mechanism of action (MOA) of H1 antagonists? -✓✓H1 antagonists
work by blocking H1 histamine receptors.
• What effect do H1 antagonists have on histamine in the body? -✓✓They help to
reduce the effects of histamine in the body.
• How does blocking histamine action affect wakefulness? -✓✓Blocking
histamine action can lead to sedation and help induce sleep.
• What is a common side effect of H1 antagonists when used as a sleep aid? -
✓✓Daytime Drowsiness: Users may experience lingering sedation the next day.
• What are some anticholinergic effects of H1 antagonists? -✓✓Dry mouth,
blurred vision, constipation, and urinary retention.
• What CNS effects can H1 antagonists cause, particularly in older adults? -
✓✓Dizziness, confusion, and incoordination.
• What is the effect of H1 antagonists on urticaria? -✓✓Diminishes redness,
itching, and swelling.
,• Which first-generation H1 antagonists are effective for motion sickness? -
✓✓Promethazine and dimenhydrinate.
• How do certain H1 antagonists help with motion sickness? -✓✓They inhibit
muscarinic receptors.
• Why are first-generation H1 antagonists included in sleep aids? -✓✓For short-
term management of sleep disturbances.
• What are the anticholinergic effects that older adults are more susceptible to? -
✓✓Dizziness, confusion, and sedation.
• Why should first-generation antihistamines be used cautiously in older adults? -
✓✓They can increase sedation and anticholinergic effects, raising the risk of falls
and accidents.
• What criteria advises against the use of first-generation antihistamines in older
adults? -✓✓Beers Criteria.
• What is a concern regarding polypharmacy in older adults? -✓✓Increased risk of
drug interactions and cumulative side effects.
• What effect can first-generation antihistamines have on children? -✓✓They can
cause paradoxical excitation, leading to increased agitation or insomnia.
• What is advised for the use of antihistamines in infants? -✓✓Over-the-counter
cold remedies should generally be avoided in children under four years old.
, • What is the Pregnancy Risk Category for antihistamines? -✓✓Category C,
meaning they should only be used if benefits outweigh risks.
• Which type of antihistamines are often preferred during pregnancy? -✓✓Second-
generation antihistamines due to a better safety profile.
• What should be considered regarding antihistamines and breastfeeding? -
✓✓Caution is advised as they can pass into breast milk; consultation with a
healthcare provider is recommended.
• How can age-related changes affect the use of antihistamines? -✓✓They can
alter pharmacokinetics, affecting metabolism and excretion.
• What should be considered regarding family support in medication management?
-✓✓The ability of the family to manage medication regimens, especially in older
adults and children.
• What is a key difference in sedation between 1st and 2nd generation H1
antagonists? -✓✓First-generation causes significant sedation; second-generation is
less sedating.
• How do the mechanisms of 1st and 2nd generation H1 antagonists differ? -
✓✓First-generation affects both H1 and muscarinic receptors; second-generation
primarily targets H1 receptors.
• What are the primary use cases for 1st generation H1 antagonists? -✓✓Used for
a broader range of conditions, including insomnia and motion sickness.