- Antihistamines: how to neutralize the negative effects of histamine?
- Blockers of histamine H2-receptor
- Nizatidine and ranitidine
- Side effects when taking H2-blockers of histamine receptors
- Antagonists of histamine H2 receptor
Antihistamines - a group of drugs that suppress the action of histamine receptors in the body. Antihistamines relieve spasm induced by histamine bronchial smooth muscle and intestine, reducing capillary permeability, prevent the development of edema
Prevention and treatment of edema - it is important to understand the root cause
tissues and facilitates the allergic reactions.
Many antihistamines are available without a prescription, such as drugs of the first generation: brompheniramine (dimetapp, bromfen, dimethano, nazahist), chlorpheniramine (chlor-trimeton), clemastine (allergist, tavist) and diphenhydramine (Benadryl) and an antihistamine of the second generation loratadine (Claritin). One of the main advantages of Loratadine (Claritin) that it does not cause drowsiness.
By antihistamines, prescription (drugs is a second-generation) include cetirizine (Zyrtec), desloratadine (klarineks) and fexofenadine (Allegra). These antihistamines (and loratadine) have less side effects, in particular, does not cause drowsiness and dry mouth.
Some antihistamines, nasal sprays (e.g., azelastine), are also suitable for the treatment of symptoms such as runny nose, sneezing, and itchy nose.
Antihistamines for the first time have been used successfully to treat people in 1942. First antihistamine developed Bernard Halpern. In 1944, the drug has been improved, and in 1946 went on sale in the US as diphenhydramine and tripallanamin. With the introduction of the first generation antihistamines - ethylene diamine, ethanolamines, alkylamines, piperazine, tritsiklidov - by 1950 the ninth year antihistamines have gained immense popularity worldwide.
Types of antihistamines
Ethylenediamine - the first clinically effective group of antihistamines. On this basis, they developed ethanolamines, which, in turn, became the basis for benedrila, OTC that cause drowsiness, but was considered very effective.
Ethanolamines were also used in the popular medicines for hay fever, intended for children, because they had a pleasant taste. Molecular variation of ethanolamines was the basis for SNCR.
Alkyl amines have been designed in such a way to reduce sleepiness. This non-prescription drugs, which are used to treat colds, ie, elimination of their symptoms: sneezing, runny nose and watery eyes. Alkylamino - antihistamine component in Visine-A. Piperazine - an antihistamine developed for the impact on parts of the brain that are responsible for the occurrence of nausea and vomiting, dizziness,
Dizziness - if the ground is slipping from under his feet
and motion sickness. Tritsiklidy - antihistamines, antidepressants are meant to be, but now used mainly to eliminate toxicity, nausea and sedation.
Antihistamines are the second generation
Antihistamines are the second generation does not have a sedative action and have fewer side effects. They also differ in their structure and effect. These antihistamines were introduced in 1981. The first second-generation drugs became ranitidine
Ranitidine - help in the prevention of relapse of peptic ulcer
And by the end of the 1980s it ranked first among the prescription drugs.
Antihistamines are the third generation
Third generation of antihistamines have been developed in the 1990s and has a greater efficiency and almost complete lack of side-effects including drowsiness. This generation of drugs developed for the potential treatment of Alzheimer's disease. Further studies are directed at improving the efficiency of antihistamines and reducing their side effects.
The mechanism of action of antihistamines
Antihistamines displace histamine from biochemical tissue systems and block the receptors of smooth muscle cells and glands, thereby preventing occurrence of allergic symptoms. Antihistamines are most effective if taken continuously throughout the season (for seasonal allergies).
Who are counter antihistamines
Antihistamines are contraindicated in case of hypersensitivity to its active components. They can cause unwanted side effects in the following cases:
- when taken with monoamine oxidase inhibitors (MAOIs);
- in patients with glaucoma
Glaucoma - a perspective possible blindness
- in nursing mothers.
The use of antihistamines
Antihistamines are produced in the form of tablets, chewable tablets, capsules and liquids. The frequency of dosing depends on the specific characteristics and type (its dosage forms and dosage).
Reaction with Food and Drug Administration
Do not take other drugs and foods that cause drowsiness, such as alcohol, sedatives or tranquilizers when using antihistamines. Also, do not take MAO inhibitors (eg, isocarboxazid [Marplan], phenelzine sulfate [Nardil], or tranylcypromine [Parnat]) within fourteen days after the completion of antihistamines.
Side effects of antihistamines
Many antihistamines (particularly first-generation drugs) may cause the following side effects:
- dry mouth;
- urinary retention;
- loss of visual acuity.
Before taking antihistamines, consult your doctor.