How allergies are caused?
People get allergic reactions when they are exposed to allergens. Allergens are substances that cause abnormal secretion of histamines from the immune system. However, types of allergens can be varied from person to person. For an example some people may be allergic to tomatoes and others may be allergic to tuna fish, but not allergic to tomatoes.
Histamine is a naturally occurring chemical that is secreted from the immune system. Histamine acts on various tissues which cause the symptoms of allergy. Medications that are prescribed in allergies inhibit the action of histamine or lower the potency of the immune system in general.
What are the medications prescribed in allergy?
There are numerous anti-allergy medications available as over the counter or prescription only form. However, most over the counter medications such as Diphenhydramine can cause drowsiness. They can even cause weight gain in long term use. It is because they cross the blood brain barrier and enter into the brain in large amounts.
What are the best drugs that are prescribed for allergies?
However, newer antihistamines do not cross the blood brain barrier in large amounts. Therefore they cause less drowsiness. In addition they cause less weight gain. Following drugs are prescribed commonly in allergies.
Cetirizine (Zyrtec®)
Cetirizine is categorized as a non-sedating antihistamine. However, it can cause some sedation in practice. It is usually available as tablets and syrups. In addition, it is usually prescribed once a day.
Levocetirizine (Xyzal®)
This is an isomer of the drug cetirizine. It is similar to cetirizine. Therefore it can also cause some sedation. Levocetirizine is available as tablets and syrups.
Loratidine (Claritin®)
This medication is a non-sedating antihistamine. Compared to cetirizine, it produces minimal or no drowsiness. It is also given in convenient once daily dosage.
Desloratidine (Clarinex®)
This is a derivative of the drug Loratidine. It also causes minimal drowsiness. This medication is available as tablets and syrups.
Fexofenadine (Allegra® or Telfast ®)
Compared to other allergy medications fexofenadine is a rather newer drug. It causes minimal drowsiness and sedation. Similar to above drugs, this is also given once a day.
Steroids
Sometimes steroids are prescribed to treat allergies. In addition, they are usually given in life threatening anaphylactic reactions. Steroids are also given in resistant allergies that do not respond to antihistamines.
Montelukast (Singulair®)
This medication acts by inhibiting the leukotriene receptors and preventing the action of naturally occurring interleukins. Recent studies have found that it is quite effective in people with allergies associated with bronchial asthma [2]. This medication is usually given to patients with long term allergies.
Summary
Allergic symptoms are common in primary care. However some medications that are available for this condition can cause drowsiness and weight gain. But newer medications can be taken once daily and they cause fewer side effects.
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