PC707 Module 6 Respiratory 2026 Exam
Questions and Correct Answers | New
Update
What are H1RAs - 🧠 ANSWER ✔✔-H1 receptor is the main receptor that
involves creating symptoms during allergic reactions.
-H1 receptors are observed in the periphery of the body, especially in the
smooth muscles. Apart from the periphery, H1 receptors reside in the
adrenal medulla, vascular endothelium, heart, and central nervous system.
-The functions mediated by H1 receptor bindings are a contraction of
smooth muscles, an increase in capillary permeability, mediating
neurotransmission in the central nervous system, among other necessary
functions.
,-H1 receptors are used to treat mild allergic disorders.
What are H2RAs - 🧠 ANSWER ✔✔-H2 receptor is another histamine
binding receptor. The wide distribution of H2 receptors can be seen in the
central nervous system especially in the brain.
-Receptor concentration is high in the basal ganglia, hippocampus,
amygdala, and cerebral cortex. H2 receptors are also present in the
parietal cells located in the stomach. They are responsible for regulating
the gastric acid level. H2 receptors can be seen in the heart, uterus, and
vascular smooth muscle cells.
-The binding of histamine blockers to H2 receptors can reduce the amount
of acid produced by the stomach. Hence, H2 receptor blockers are used to
treat duodenal ulcers, gastric ulcers, and Zollinger -Ellison disease (among
other gastric-acid mediated conditions).
Which histamine receptor antagonist has generations? - 🧠 ANSWER ✔✔-
The H1 receptor antagonists are broken down to 1st generation
antihistamines and 2nd generation antihistamines.
-Antihistamines will not treat the cause of rhinorrhea and sneezing with a
cold, as symptoms are not related to an allergen. In fact, it's their
,secondary effect (the anticholinergic side effect of antihistamines) that may
provide relief by drying the mucous membranes and nasal secretions.
-1st generations are HIGHLY sedative compared to 2nd generation.
1st generation H-1 antagonist antihistamines: - 🧠 ANSWER ✔✔relatively
quick onset of action of about 15 minutes to 30 minutes. With regular use,
tolerance or drug failure occurs after several weeks to months. This is
because antihistamines can induce the production of hepatic enzymes that
actually break them down (they help with their own destruction).
-The older or 1st generation crosses the blood-brain barrier, hence the
sedative effects. As these drugs block the histamine receptors (remember,
they are located in the central nervous system), they also end up slowing
down neuronal firing and the production of neurotransmitters, resulting in
sedative effects. The sedation can lead to impaired learning and memory;
use sparingly if at all.
2nd generation H-1 antagonists antihistamines: - 🧠 ANSWER ✔✔act
peripherally, so these H1 receptor blockers are less sedating. Why don't
the 2nd generation antihistamines exert sedative effects? These drugs are
large molecules, have low lipid solubility, and can't cross the blood-brain
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, barrier. They have a low affinity for the histamine receptors in the brain. If
they do cross the blood-brain barrier, it is in negligible amounts.
**The only exception is cetirizine/Zyrtec, as it's the one 2nd generation with
a long half-life and sedative effects.
-Be cautious recommending in those for whom sedation could impair their
functioning (e.g., pilots).
-As a class, the onset is about 1-2.5 hours. To reach a steady-state it takes
1-3 days, but food can impair their absorption.
-The 2nd generation H1 receptor antagonists are generally, well-tolerated,
but a headache, dry mouth, dyspepsia, nausea, and fatigue may occur.
-Fexofenadine (Allegra) may interact with antifungals, causing
concentrations of this antihistamine to become increased. ***Fexofenadine
(Allegra) can also prolong QT intervals if combined with other drugs that
prolong the QT interval.
What are anticholinergic side effects with antihistamines - 🧠 ANSWER
✔✔·antihistamines have low receptor specificity and interact with both
peripheral and central histamine receptors and readily cross the blood-
brain barrier. This leads to significant central nervous system side effects,
Questions and Correct Answers | New
Update
What are H1RAs - 🧠 ANSWER ✔✔-H1 receptor is the main receptor that
involves creating symptoms during allergic reactions.
-H1 receptors are observed in the periphery of the body, especially in the
smooth muscles. Apart from the periphery, H1 receptors reside in the
adrenal medulla, vascular endothelium, heart, and central nervous system.
-The functions mediated by H1 receptor bindings are a contraction of
smooth muscles, an increase in capillary permeability, mediating
neurotransmission in the central nervous system, among other necessary
functions.
,-H1 receptors are used to treat mild allergic disorders.
What are H2RAs - 🧠 ANSWER ✔✔-H2 receptor is another histamine
binding receptor. The wide distribution of H2 receptors can be seen in the
central nervous system especially in the brain.
-Receptor concentration is high in the basal ganglia, hippocampus,
amygdala, and cerebral cortex. H2 receptors are also present in the
parietal cells located in the stomach. They are responsible for regulating
the gastric acid level. H2 receptors can be seen in the heart, uterus, and
vascular smooth muscle cells.
-The binding of histamine blockers to H2 receptors can reduce the amount
of acid produced by the stomach. Hence, H2 receptor blockers are used to
treat duodenal ulcers, gastric ulcers, and Zollinger -Ellison disease (among
other gastric-acid mediated conditions).
Which histamine receptor antagonist has generations? - 🧠 ANSWER ✔✔-
The H1 receptor antagonists are broken down to 1st generation
antihistamines and 2nd generation antihistamines.
-Antihistamines will not treat the cause of rhinorrhea and sneezing with a
cold, as symptoms are not related to an allergen. In fact, it's their
,secondary effect (the anticholinergic side effect of antihistamines) that may
provide relief by drying the mucous membranes and nasal secretions.
-1st generations are HIGHLY sedative compared to 2nd generation.
1st generation H-1 antagonist antihistamines: - 🧠 ANSWER ✔✔relatively
quick onset of action of about 15 minutes to 30 minutes. With regular use,
tolerance or drug failure occurs after several weeks to months. This is
because antihistamines can induce the production of hepatic enzymes that
actually break them down (they help with their own destruction).
-The older or 1st generation crosses the blood-brain barrier, hence the
sedative effects. As these drugs block the histamine receptors (remember,
they are located in the central nervous system), they also end up slowing
down neuronal firing and the production of neurotransmitters, resulting in
sedative effects. The sedation can lead to impaired learning and memory;
use sparingly if at all.
2nd generation H-1 antagonists antihistamines: - 🧠 ANSWER ✔✔act
peripherally, so these H1 receptor blockers are less sedating. Why don't
the 2nd generation antihistamines exert sedative effects? These drugs are
large molecules, have low lipid solubility, and can't cross the blood-brain
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, barrier. They have a low affinity for the histamine receptors in the brain. If
they do cross the blood-brain barrier, it is in negligible amounts.
**The only exception is cetirizine/Zyrtec, as it's the one 2nd generation with
a long half-life and sedative effects.
-Be cautious recommending in those for whom sedation could impair their
functioning (e.g., pilots).
-As a class, the onset is about 1-2.5 hours. To reach a steady-state it takes
1-3 days, but food can impair their absorption.
-The 2nd generation H1 receptor antagonists are generally, well-tolerated,
but a headache, dry mouth, dyspepsia, nausea, and fatigue may occur.
-Fexofenadine (Allegra) may interact with antifungals, causing
concentrations of this antihistamine to become increased. ***Fexofenadine
(Allegra) can also prolong QT intervals if combined with other drugs that
prolong the QT interval.
What are anticholinergic side effects with antihistamines - 🧠 ANSWER
✔✔·antihistamines have low receptor specificity and interact with both
peripheral and central histamine receptors and readily cross the blood-
brain barrier. This leads to significant central nervous system side effects,
