Study Set Content:
A few (blank) (eg, terfenadine, acrivastine)
have been shown to inhibit the P-glycoprotein
transporter found in cancer cells, the epithelium of the gut,
and the capillaries of the brain. The significance of this
effect is not known.
H1 antagonists
are often the first drugs used to
prevent or treat the symptoms of allergic reactions.
H1 antihistaminic agents
In allergic rhinitis (hay fever), the H1 antagonists are second-
line drugs after (blank) administered by nasal spray.
glucocorticoids
in which histamine is the primary mediator, the H1
antagonists are the drugs of choice and are often quite effective
if given before exposure.
urticaria,
However, in bronchial asthma, which
involves several mediators, the H1 antagonists are largely
ineffective
may be precipitated by histamine release but appears
to be maintained by peptide kinins that are not affected by
antihistaminic agents.
Angioedema
For (blank), antihistaminic drugs such as
diphenhydramine are used mostly for their sedative side effect,
which reduces awareness of itching.
atopic dermatitis
The H1 antihistamines used for treating allergic conditions such as
hay fever are usually selected with the goal of minimizing sedative
effects; in the US, the drugs in widest use are the
alkylamines and
the second-generation nonsedating agents.
Sedative effects and
the therapeutic efficacy of different agents vary widely among
individuals
The second-generation H1 antagonists are used mainly for the
treatment of
allergic rhinitis and chronic urticaria.
Several double-blind comparisons with older agents (g,
chlorpheniramine) indicated about
equal therapeutic efficacy.
However, sedation and interference with safe operation of
machinery, which occur in about 50% of subjects taking first- generation antihistamines, occurred in only about(blank) of subjects
taking second-generation agents.
7%
and certain first-generation H1 antagonists are the
most effective agents available for the prevention of motion
sickness.
Scopolamine
The antihistaminic drugs with the greatest effectiveness in this
application are
diphenhydramine and promethazine.
which is promoted almost exclusively for the
treatment of motion sickness, is a salt of diphenhydramine and has
similar efficacy.
Dimenhydrinate,
also have significant
activity in preventing motion sickness and are less sedating than
diphenhydramine in most patients.
The piperazines (cyclizine and meclizine)
Both scopolamine and the H1 antagonists are more effective in
preventing motion sickness when combined with
ephedrine or
amphetamine.
The (blank) were withdrawn from such use when it
was demonstrated that they have teratogenic effects in rodents.
piperazine derivatives
an ethanolamine H1 antagonist, was promoted for
this NAUSEA AND VOMITING OF PREGNANCY as a component of Bendectin, a prescription
medication that also contained pyridoxine.
Doxylamine,
Possible (blank) of doxylamine were widely publicized in
the lay press after 1978 as a result of a few case reports of fetal
malformation that occurred after maternal ingestion of Benedictin
teratogenic effects
