The mechanism of action of antihistamines
Allergic reaction with various symptoms, causes Allergy, affects in the body begins to produce biologically active substances, the excess of which leads to allergic inflammation. These substances are many, but the most active is histamine, which in its ordinary state contains in fat cells and is biologically neutral. Becoming active under the action of the allergen, histamine causes appearance of such irritating and discomforting symptoms, such as skin rashes and itching, swelling and runny nose, conjunctivitis and redness of the eyes, spasm of the bronchi, lowering blood pressure, etc. Antihistamines prevent, reduce or eliminate symptoms of allergies by reducing the histamine release in blood or neutralizing it.
What are antihistamines
These drugs are divided into two groups. The first is traditionally used for the relief of allergic symptoms diphenhydramine, promethazine, suprastin, tavegil, diazolin and fenkarol, they are called preparations of the old generation. They all usually have one thing in common a side effect – cause drowsiness. The new generation of drugs include, for example, astemizole (hismanal) and claritin (loratadine). The main difference between these two groups of antihistamines that new generation drugs do not have a sedative effect and should take them once a day. True, the cost of these drugs is much higher than "classic".
Other pharmacological properties of antihistamines
In addition to the suppression and neutralization of histamine, these drugs possess other pharmacological properties that should be considered if you're buying them without a prescription. So, most of them have the ability to enhance the action of other drugs, so often as the gain of the anesthetic effect is used, for example, such a combination as analgin and Dimedrol. These drugs also enhance the effectiveness of drugs affecting the Central nervous system, so their joint reception can cause overdose and have unpredictable consequences.
Acute respiratory diseases of not recommended to take Allergy medications like diphenhydramine, promethazine, suprastin or tavegil. They also dry mucous membranes and make it more dense and viscous mucus produced in the lungs, not allowing her to cough up, which may increase the risk of developing pneumonia. There are other side effects of antihistamines, which are known only to specialists, so before you take something, consult your doctor.
Advice 2: How to choose an antihistamine
The right choice of antihistamines helps to get rid of unpleasant symptoms of allergies to prevent allergic reactions and deal with a lot of associated with the occurrence of allergic diseases. Despite the huge variety of this type of drugs on the shelves of pharmacies, to choose the most suitable and really good but not so difficult.
The effectiveness of antihistamines first-generation in the presence of already developed pronounced symptoms of allergies low. However even this circumstance did not affect the popularity of their use. Antihistamines of the first generation are required components of many complex preparations aimed at treating colds and strengthening the effectiveness of local anesthetic drugs.
A significant drawback of antihistamines first-generation is that they have such side effects as drowsiness.
As an independent drug they used most often to eliminate discomfort and pain from burns, insect bites, minor injuries and cuts. They are frequently used to help people affected by motion sickness in the transport and seasickness. The use of antihistamines first-generation allows to prevent the occurrence of episodic, seasonal allergic reactions, to exclude the development of food and drug allergies, and to eliminate the symptoms of urticaria, angioedema and anaphylactic shock.
The most popular and effective antihistamines first-generation is defined as: "Suprastin", "Tavegil", "Help", "Core" and "Diphenhydramine".
Antihistamines second generation
Antihistamines second generation, such as "Ketotifen" and its analogues are prescribed by the doctors extremely rare and is most often used to treat such diseases as bronchial asthma and atopic dermatitis. Most doctors are trying to replace this group of drugs antihistamines third-generation.
According to experts and responses of patients, antihistamines third-generation lack many of the shortcomings of the available drugs first and second generation, therefore you can use them for the prevention of allergic reactions, and long-term treatment of allergies.
The main advantage of antihistamines third-generation is the lack of side effects from the nervous system.
Often antihistamines third-generation are used for the treatment of asthma, chronic contact dermatitis, urticaria, hay fever and autoimmune diseases. Also experts recommend the use of antihistamines third-generation people, important role in professional activities which are concentration, clarity of thinking and speed of reaction.
The most popular antihistamines in this group are: "claritin", "Castin", "Zyrtec", "Allergodil", "Telfast" and "Liebsten".