Study Set Content:
Nonetheless, because of the continuing controversy, adverse
publicity, and lawsuits, the manufacturer of Bendectin (blank) the
product from the market.
withdraw
Several of these effects have been
used for therapeutic purposes, especially in over-the- counter
remedies.
(sedation, antimuscarinic action)
Less common toxic effects of systemic use includes:
excitation and convulsions in children
postural hypotension
allergic responses
is relatively common after topical use of H1
antagonists.
Drug allergy
The effects of severe systemic overdosage of the older agents
resemble those of atropine overdosage and are treated in the same
(blank)
way
(blank) occurred in several patients taking
either of the early second-generation agents, terfenadine or
astemizole, in combination with ketoconazole, itraconazole, or
macrolide antibiotics such as erythromycin.
Lethal ventricular arrhythmias
These antimicrobial drugs inhibit the metabolism of many
drugs by (blank) and cause significant increases in blood
concentrations of the antihistamines.
CYP3A4
The mechanism of this toxicity involves blockade of the potassium
channels in the heart that contribute to repolarization of the action
potential. Both (blank)were withdrawn from
the US market in recognition of these problems.
terfenadine and astemizole
also inhibits CYP3A4 and has been shown to
increase blood levels of terfenadine significantly.
Grapefruit juiceGrapefruit juice
For those H1 antagonists that cause significant sedation, concurrent
use of other drugs that cause(blank) produces additive effects and is contraindicated while
driving or operating machinery.
central nervous system
depression
Molecular manipulation of the histamine molecule resulted in drugs
that blocked acid secretion and had no H1 agonist or antagonist
effects. Like the other histamine receptors, the H2 receptor displays
constitutive activity, and some H2 blockers are
inverse agonists.
The high prevalence of peptic ulcer disease created great interest in
the therapeutic potential of the(blank) when first
discovered. Although these agents are not the most efficacious
available, their ability to reduce gastric acid secretion with very
low toxicity has made them extremely popular as over-the-counter
preparations.
H2 -receptor antagonists
H2-receptor antagonist drug ex:
: cimetidine, ranitidine, nizatidine,
famotidine
an
inverse H3 -receptor agonist, has been shown to reduce sleep cycles
in mutant mice and in humans with narcolepsy.
Tiprolisant,
have potential in chronic inflammatory conditions such
as asthma, in which eosinophils and mast cells play a prominent
role.
H4 blockers
No (blank) is available for use in humans.
selective H4 ligand
Several studies have suggested that (blank) may
be useful in pruritus, asthma, allergic rhinitis, and pain conditions.
H4-receptor antagonists
may be of value in sleep disorders, narcolepsy,
obesity, and cognitive and psychiatric disorders.
H3-selective ligands
