Antihistamines.
Antihistamines are a family of drugs that interfere with the action of histamine and prevent the appearance of the effects of this biochemical compound by blocking the relevant receptors. During an allergic episode, the immune system reacts and histamine is secreted and binds to the surface of cells. This may result in rash, pain, constriction of bronchi, headache, vascular permeability. The allergic reaction may also lead to vasodilatation which, in turn, causes drop of blood pressure, increased heart beat and flushes. The severity of these symptoms varies, depending on the body sensitivity against an allergenic. In many cases, such an immune reaction is just annoying but occasionally it may get life-threatening, especially if it causes major breathing difficulties. Antihistamines are the primary medications used to prevent or control allergic reactions, like hives, hey fever, rhinitis, angioedema, conjunctivitis, and certain dermatologic symptoms, such as severe itching, caused by conditions like eczema.
Depending on when the drug has been released, antihistamines are classified as older and newer ones.
The antihistamines included in the former category, apart from the anti-allergic properties, present sedative action and they are mainly used to minimize or eliminate severe itching. In fact, because of this sedative action such antihistamines are contained in numerous sleeping-aid preparations. However, in some people insomnia can be an unexpected aftermath of the use of first generation antihistamines. Certain antihistamines, such as Gravol or Dramamine, are available over-the-counter and they are taken to prevent travel sickness. Other side-effects of antihistamines include blurred vision, impaired coordination, palpitations, tremor, anxiety, reduced saliva secretion, headache, constipation and diarrhea. Older antihistamines should never be taken in combination with tranquilizers or alcohol, because the sedative result will be maximized and the blood pressure may drop at very dangerous levels. In any case, the first generation antihistamines should never be taken before tasks that require the person to be alert.
Antihistamines of newer versions have less or do not have any sedative properties at all and they present far fewer side-effects. The latest can be headache, tiredness and nausea.
In the table below, you can find the most commonly used antihistamines. If you have been prescribed any of them, you will be able to find it online by trying the relevant link in the right column.
You may need a valid prescription for your medication purchase.
We strongly recommend generic forms of a medicine, whenever they are available, rather than brand-names. A generic drug is a copy that is the same as a brand-name one in dosage, safety, strength, the way it is taken, quality, performance and intended use. The big advantage is that a generic drug can be up to 80% less expensive in comparison to an equivalent brand-named counterpart. Today almost half of all prescriptions are filled with generic medicines. For more information about generic drugs you can visit the Frequently Asked Questions page on this site.
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