Preparations from an allergy
Treatment of all allergic diseases is carried out in almost the same way and consists in the obligatory isolation of the patient from contact with the provoking substance-allergen; in the conduct of specific immunotherapy, which helps to teach the body do not show hyperreaction to the ingested allergen; in nonspecific therapy, which consists in taking anti-inflammatory non-steroid drugs, corticosteroids and antihistamines
Antihistamines from allergies
Antihistamines are medicines, the main action of which is aimed at blocking H1-histamine receptors. Also, there are drugs that block H2-histamine receptors, which are often used as antiulcer drugs, because they reduce secretion.
Thanks to numerous studies, it was found that histamine, affecting the receptors of the skin, eyes and respiratory system, causes allergy symptoms that antihistamines stop or prevent. Antihistamines prevent the bronchospasm caused by histamine-like substances and the histamine itself and have local anesthetic, sedative, antiserotonin, anticholinergic, antispastic, anti-edematous and antipruritic actions.
By the time of creation, antihistamines are divided into preparations of I, II and III generations. Preparations of the first generation - sedatives, preparations of the second generation - non-sedatives, third generation drugs - active metabolites without cardiotoxic and sedative effects
Antihistamines of the first generation
Preparations of the first generation are reversibly linked to H1-receptors, as a result of which they must be administered frequently, in sufficiently large dosages. The main pharmacological properties of these drugs: hypnotic, sedative, anticholinergic action and a decrease in muscle tone. Also, these drugs can potentiate the effects of alcohol. They have a protivogistaminny effect for about five hours (Tavegil drug - about eight hours).
The sedative effect arises from the fact that practically all preparations of the first generation are fat-soluble, easily penetrate the blood-brain barrier, linking to the H1-receptors of the brain. In the case of combination with psychotropic drugs and alcohol, the sedative effect is enhanced. In some cases, there may be a psychomotor agitation. It is because of the sedative effect of most first-generation drugs that it is forbidden to use it when carrying out actions requiring increased attention. All without exception preparations of the first generation enhance the effect of alcohol, monoamine oxidase inhibitors, non-narcotic and narcotic analgesics, hypnotics and sedatives.
Anticholinergic action of these drugs causes atropine-like reactions, manifested by visual impairment, tachycardia, constipation, urinary retention, dryness in the nasopharynx and mouth. In rhinitis, these properties can be useful, and in bronchial asthma, they can only increase airway obstruction, cause an exacerbation of prostate adenoma and glaucoma.
Due to holinoliticheskomu action, the drugs have anti-soothing and antiemetic effects, which significantly reduces the symptoms of Parkinsonism.
For most antihistamines, cocaine-like (local anesthetic) action is characteristic.
In the case of long-term use, antihistamine activity may decrease, therefore it is recommended to change the drugs every two to three weeks. After taking medications, the medical effect is observed almost immediately, however, its effect is quite short-lived.
Several antihistamine preparations of the first generation, because of their hypnotic and soothing effect, are part of the combined preparations used for motion sickness, migraine and cold.
The first generation of antihistamines have such a wide range of side effects that they are often rejected for allergic diseases, and in some European countries, their implementation is generally prohibited.
Below we will present the most frequently used antihistamine preparations of the first generation:
. • Dimedrol . Reduces the severity of pseudoallergic and allergic reactions, has a high antihistaminic activity. Due to its anticholinergic effect, anti-emetic and antitussive effects, while often causing a delay in urination and dry mucous membranes. In addition, diphenhydramine has a strong hypnotic and sedative effect and is often used as a normal sleeping pill. In case of individual intolerance of lidocaine or / and novocaine, diphenhydramine is their alternative in terms of local anesthetic effect. In this case, this drug is characterized by unpredictable effects on the central nervous system and a fairly wide range of side effects
. • Diazolin . In this drug, the sedative effect is much weaker than that of dimedrol, and it often causes CNS excitement and such side effects as inhibition of mental and motor reaction, drowsiness, dizziness , impaired urination, irritation of the gastrointestinal mucosa. Some researchers argue that diazoline has a toxic effect on nerve cells
. • Suprastin . The most used sedative antihistamine drug, which has moderate antispasmodic and peripheral anticholinergic action, as well as significant antihistaminic activity. Suprastin most effectively proved itself in the treatment of such diseases as year-round and / or seasonal allergic rhinoconjunctivitis, atopic dermatitis , eczema, Quincke's edema and urticaria . Due to the fact that this drug does not accumulate in the blood serum, it can be used for a long time without the threat of overdose. The therapeutic effect occurs quickly enough, however, it does not last long, therefore, to increase its duration, its combined administration with non-sedative H1-blockers
. • Tavegil . By its action, a dimedrol-like highly effective antihistamine with high anticholinergic activity. Sometimes, as an additional remedy, it is injected with angioedema and anaphylactic shock. According to the indications it can be used to treat pseudoallergic and allergic reactions. However, sometimes there is an allergy to Tavegil himself
. • Peritol . In addition to antihistamine, this drug has a considerable antiserotonin effect, significantly increases appetite and is often used for migraines
• Fenkarol. Despite the fact that this drug antihistamine activity is less than that of dimedrol, it has a lower severity of sedative properties. In addition to reducing histamine in tissues, Fenkarol blocks H1-receptors. This drug serves as a good substitute in case of getting used to other antihistamines
. • Pipolphen . It is used to potentiate anesthesia and as an antiemetic. Has a pronounced effect on the central nervous system
Antihistamines of the second generation
Antihistamines from allergy of the second generation, in contrast to their predecessors, do not have cholinolytic and sedative effects, do not reduce physical and mental activity, do not penetrate the blood-brain barrier, do not adsorb with products in the digestive tract, have a rapidly advancing therapeutic effect. However, despite their clear advantage over preparations from allergies, generations have passed, second-generation drugs have cardiotoxic effect of varying degrees, therefore their reception requires a constant outpatient control of cardiac activity. These drugs are banned for use by the elderly and patients with any disability in the work of the cardiovascular system.
The effect of these drugs lasts longer and comes faster. In the case of the use of drugs in the recommended therapeutic dosage, the sedative effect is minimal. Moderate drowsiness can occur only in people with heightened sensitivity, however, this does not require drug withdrawal. With prolonged use, antihistamine activity does not decrease.
Side-effect cardiotoxic effect arises due to blocking the potassium channels of the cardiac muscle with the drug. The risk of developing a cardiotoxic effect is significantly increased in the case of combination of antihistamines with antidepressants (paroxetine, sertraline, fluoxetine), macrolides (clarithromycin, erythromycin) and antifungal agents (intraconazole, ketoconazole).
The most used antihistamines are the second generation:
. • Trexyl (Terfenadine) . This drug for allergies is the first drug of this generation. Despite the fact that it does not have a depressant effect on the part of the central nervous system, it has an increased ability to provoke the development of fatal arrhythmias and a significant cardiotoxic effect
. • Histalong (Astemizole) . The most long-acting (about 20 days) drug from this group. Gistalong does not interact with alcohol, the sedative effect is almost completely absent. The most effective has proved itself in the treatment of chronic allergic diseases. When the acute process proceeds, its use is considered impractical. The main serious contraindication is the risk of development (sometimes even fatal) of cardiac arrhythmias
. • Semprex (Acryvastin) . The therapeutic effect with the use of this drug is short-lived, but it is achieved very quickly. This drug with minimal anticholinergic and sedative effects with high antihistamine activity
. • Fenistil (Dimetenden) . By its composition is the closest to the drugs from the allergy of the last generation, but it differs markedly from them by a much smaller degree of sedation, longer duration of action and higher antiallergic activity. Practice is the release form in the form of a gel for external use
. • Claritin (Loratadin) . The most purchased drug of the second generation. Due to greater binding strength to H1 receptors, antihistamine activity is higher in him than in Terfenadine and Astemizol. The drug does not potentiate the effect of alcohol, the sedative effect is absent, cardiotoxic effect does not possess, with other medicinal products practically does not interact. Claritin can be taken to children after a year and drivers
Metabolites (3rd generation antihistamines)
New drugs from the third generation allergy do not have cardiotoxic and sedative effects, which is why they are allowed to be consumed by people employed in industries that require increased attention.
The most used new drugs for allergy of the third generation:
. • Telfast (fexofenadine) . The drug does not interact with other drugs, does not affect the psychomotor activity, does not have a sedative effect. Among all antihistamines, Telfast can be considered the most effective and safest
. • Cetrine, Zirtek . In the body, the drug is not practically metabolized, the rate of its withdrawal directly depends on the function of the kidneys. Well established itself with skin allergic manifestations, tk. very easily penetrates into the skin. The therapeutic effect manifests itself within two hours from the moment of taking the drug and lasts for about a day. When taken in average therapeutic doses, cardiotoxic and sedative effects are absent. In the case of impaired renal function, the drug should be taken with extreme caution
Nasal decongestants from allergies
Most antiallergic drugs contain such amphitamin-like substances as pseudoephedrine hydrochloride or components found in cold medicines used for colds. Such side effects as cardiovascular disorders, insomnia and nervousness usually arise when allergic reactions are treated with these drugs. In addition, decongestant nasal preparations are allergic symptomatology (sore throat, cough, sneezing, watery and itchy eyes, runny nose) do not remove, but are able to cure only the stuffiness of the nose, which is by no means the main annoying allergic symptom.
Nasal decongestants recommended by manufacturers without the effect of "drowsiness": Sudafed and Afrinol. However, for allergies, it is not recommended to use them.