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Antihistamines are one of the commonly used drugs in the treatment of allergies. However, the drug has many side effects and the abuse of antihistamines can lead to complications that affect the patient's health.1. Learn Antihistamines
1.1 Antihistamines Histamine is one of the mediators that play an important role in allergic reactions and anaphylaxis. Histamine is found throughout the tissues of the body, but is not evenly distributed. Histamine is most abundantly stored in secretory granules and basophils in mast cells.
When histamine binds to H1 receptors, it causes a number of reactions with the body as follows:
On the cardiovascular system: Histamine is vasodilating and increases capillary permeability leading to edema, inflammation, itching, rash, increased heart rate, increases myocardial contractility, and causes hypotension. On the respiratory system: causes runny nose, stuffy nose, can cause bronchial smooth muscle spasm, causing asthma-like shortness of breath. On the nervous system: Histamine stimulates sensory nerve endings causing itching and pain. When histamine binds to H2 receptors, especially in gastric parietal cells, it causes increased secretion of gastric acid, easily leading to peptic ulcers.
1.2 The effect of antihistamines Basically, antihistamines competitively antagonize histamine receptors at target cells, making histamine unable to bind to receptors, so it has no effect on cells. Antihistamines are divided into 2 types corresponding to 2 types of receptors, namely H1 antihistamines and H2 antihistamines. H2 antihistamines only compete with gastric parietal cells and reduce gastric secretion where histamine is present at the H2 receptor. Therefore, H2 antihistamines are used in the treatment of peptic ulcers. As for H1 antihistamines are used in the treatment of allergies, but they are divided into 2 main groups:
First generation H1 antihistamines: distributed throughout the body, causing inhibition of the central nervous system. It causes sluggishness, drowsiness, and decreased alertness. Therefore, it is often used for anti-emetics, anti-motion sickness but causes unwanted effects that are dry mouth, nose and throat. 2nd generation H1 antihistamines do not cause central nervous system depression due to difficulty in crossing the blood-brain barrier and do not cause unwanted effects. Some drugs such as loratidine, acrivastin, cetirizine hydrochloride, fexofenadin, ...
Thuốc kháng histamin H1 giúp người bệnh giảm tình trạng say tàu xe
2. Some notes when using antihistamines in the treatment of allergies
Antihistamines are drugs that have good effect in acute allergic reactions, with symptoms such as: allergic rhinitis, runny nose, erythema, urticaria, skin rash, allergic connective tissue inflammation allergic reactions, allergic capillaritis, atopic dermatitis, or cases of insect bites, .. Besides, the drug is also used in cases of motion sickness, airplanes, nausea and vomiting in pregnancy. morning sickness and used as a sedative to induce sleep.
2.1 Cannot treat the cause Antihistamines only help treat allergy symptoms and do not treat the root cause, so the patient will not be completely cured. Therefore, to treat the root cause of the disease, it is important to find and eliminate allergens such as changes in weather, drugs, cosmetics, smoke, food,... The use of drugs Antihistamines to treat allergies need to be patient and use many times to limit recurrence.
2.2 Use in combination with other drugs In case of severe allergies such as anaphylaxis, histamine will be released massively. At this time, using only H1 antihistamines alone will not be able to solve it, but it will need to be combined with other measures such as: emergency resuscitation, use of cardiovascular drugs (adrenalin), with oxygen breathing to respiratory support,...
2.3 Do not use in case of need to be awake Some antihistamines are commonly used in medicines to treat colds, runny nose, cough, ... but they have the undesirable effect of inhibiting the nervous system. central nervous system. Therefore, the drug should not be used for cases and jobs that require alertness such as when driving a car, working at height, ... Absolutely do not drink alcohol when taking drugs.
Antihistamines have the effect of causing drowsiness, so they can be used in case of insomnia. In particular, H1 antihistamines should only be used for a short time, when allergic symptoms have decreased, the drug should be stopped, should not be used for a long time to avoid drug dependence. It should be noted when using the drug for young children, do not use it for a long time, because it can cause fatigue and affect the child's intellectual development.
2.4 Notes when using the drug for special subjects For many women during pregnancy with allergic rhinitis, bronchial asthma, urticaria or severe eczema, it is necessary to use anti-allergic drugs. However, the use of drugs must absolutely comply with the doctor's prescription, should only use drugs with sufficient evidence of safety.
Antihistamines H1 and H2 both cause many undesirable effects, so it is necessary to consult a doctor, so that the correct use of the dose and duration of the drug is required. It is necessary to monitor drug reactions when used for special subjects such as: children, pregnant and lactating women, the elderly. Antihistamines have many brand names and are bought by many people arbitrarily in cases such as motion sickness, fever, or allergies to weather, food, etc. Medicines need to be kept out of reach. For children, if the pack is not used up, it should be discarded according to regulations. Especially do not arbitrarily use drugs unless absolutely necessary.
Người bệnh nên hỏi ý kiến bác sĩ trước khi sử dụng thuốc kháng histamin H1 và H2
In summary, antihistamines are widely used in the treatment of allergies. However, care should be taken when using the drug because the drug only treats the symptoms, not the cause, besides causing many unwanted effects. Therefore, it is necessary to take the drug as prescribed by the doctor, especially the sensitive group and keep it out of the reach of children.
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