Quantcast Mechanism of Action of Antihistamines - Pharmacology V

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
e. Anaphylactic Shock. Anaphylactic shock is the most serious type of allergic
reaction. The antigen that produces the response can range from a bee sting toxin to
an antibiotic. Again, this response is produced by an antigen-antibody reaction
characterized by the sudden overwhelming release of histamine in the body. Therefore,
one would expect the effects of histamine on the body to be demonstrated. Two main
effects of anaphylactic shock on the body are severe drops in blood pressure and
impaired respiration. The drastic drop in blood pressure develops from the severe
peripheral vasodilation and the increased permeability of the capillaries. The impaired
breathing arises from bronchoconstriction. The anaphylactic reaction occurs very
rapidly after the introduction of the antigen into the patient. Unless prompt action is
taken by medically trained personnel, the patient will die in a matter of minutes.
f. Prevention or Control of Symptoms of Allergic Reactions. It is possible
to decrease or even prevent the symptoms of an allergic reaction. For a very severe
allergic reaction like anaphylactic shock, a drug that will stop the effects of histamine on
the body must be used. Moreover, the drug must produce positive physiological effects
on the body. The drug used for anaphylactic shock is epinephrine.
g. Desensitization. In some instances, it may be advantageous to prevent an
allergic reaction from occurring. Since the production of abnormal antibodies by the
plasma cells is the real beginning of the potential allergic reaction, it makes sense that if
the abnormal antibodies were not produced, a reaction would not occur when the
antigen again enters the body. The answer would then be to have only complete
(divalent) antibodies produced in the body. This is the basis of treatment to prevent an
allergic reaction. The treatment is referred to as desensitization. Here, extracts of
substances such as pollen or drugs are given to the patient in small, but increasing
doses. In time, the body produces complete antibodies, and the allergic reaction does
not occur.
4-6.
MECHANISM OF ACTION OF ANTIHISTAMINES
a. Antihistamines are drugs that compete with histamines for their receptor sites,
known as H1 and H2 receptor sites. These receptor sites are found in tissue cells, with
H1 receptors located throughout the body and H2 receptor sites found in the gastric
mucosa. The majority of available antihistamines are H1 antagonists.
b. H1 antagonists are believed to act not by opposing but by preventing the
physiologic action of histamine. This occurs because anti-histamine molecules are
chemically similar to histamine molecules. When the antihistamine binds itself to the H1
receptor site, it prevents histamine from doing the same, which effectively eliminates
histamine action.
MD0808
4-6



Medical News
Senegal monitors contacts of 1st Ebola patient
Senegalese authorities on Monday were monitoring everyone who was in...
medicalxpress.com
Snacking while watching action movies leads to overeating
Is television making us fat? An increasing amount of research...
medicalxpress.com
Quality of US diet shows modest improvement, but overall remains poor
Dietary quality in the U.S. has improved steadily in recent...
medicalxpress.com
Family dinners reduce effects of cyberbullying in adolescents
Sharing regular family meals with children may help protect them...
medicalxpress.com
Location of body fat can increase hypertension risk
People with fat around their abdominal area are at greater...
medicalxpress.com
ESC: Left or Right Nerve Stimulation Feasible in HF
BARCELONA (MedPage Today) -- Stimulation of either the right or...
medpagetoday.com
Reflections on Effect of Stand Up To Cancer
(MedPage Today) -- As Stand Up To Cancer approaches its...
medpagetoday.com
We’re taking a break for Labor Day
In honor of today’s holiday, Scope won’t be publishing today....
scopeblog.stanford.edu
We’re taking a break for Labor Day
In honor of today’s holiday, Scope won’t be publishing today....
scopeblog.stanford.edu
Can stem cells help mobility after stroke?
When Bruce Daily woke up after having lumbar surgery a...
medicalxpress.com
Gamers helping in Ebola research
Months before the recent Ebola outbreak erupted in Western Africa,...
medicalxpress.com
Police seize millions in huge fake Viagra swoop
Police in several European countries on Monday arrested 12 people...
medicalxpress.com
ESC: See It, Fix It Approach Superior in CvLPRIT
BARCELONA (MedPage Today) -- Moving beyond the lesion that triggers...
medpagetoday.com
ESC: More Ablation Not Better for Persistent Afib
BARCELONA (MedPage Today) -- Doing more radiofrequency ablation for atrial...
medpagetoday.com
Caffeine helps cancer survivors reach exercise goals
Caffeine may improve exercise capacity and reduce fatigue in cancer...
medicalxpress.com
Permanent AF doubles risk of stroke compared to paroxysmal AF
Permanent atrial fibrillation (AF) doubles the risk of stroke compared...
medicalxpress.com
Fruit consumption cuts CVD risk by up to 40 percent
Daily fruit consumption cuts the risk of cardiovascular disease (CVD)...
medicalxpress.com
Report highlights progress, challenges in health IT
(HealthDay)—Progress has been made toward widespread adoption of electronic health...
medicalxpress.com
Children's cancer death rates drop by more than 20 per cent in 10 years
The rate of children dying from cancer has dropped by...
medicalxpress.com
ESC: Heart Energy May Be Enough to Drive Pacemaker
BARCELONA (MedPage Today) -- The motion of the heart may...
medpagetoday.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +