What is Histamine?
Histamine is a protein used by the immune system to help protect the body’s cells from infection. If the immune system detects a harmful foreign organism, such as bacteria or a virus, histamine is released into nearby cells. Histamine causes small blood vessels to dilate and the surrounding skin to swell, a condition known as inflammation.
Why should I take antihistamines?
You can take antihistamines if you have allergy symptoms, such as hay fever, allergic skin rash, and skin itching. Some antihistamines block histamine receptors in the brain. They can be very beneficial for treating travel fatigue, dizziness, or nausea related to migraines.
What are the main types of antihistamines?
There are two types of antihistamines: sedating and non-sedating.
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Sedating Antihistamines: They work in the brain as well as the rest of the body, and can cause drowsiness. Examples include Chlorphenamine, Loratadine, or Cetirizine.
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Non-sedating Antihistamines: They do not easily cross into the brain, so they do not cause drowsiness, meaning they do not relieve fatigue. This type includes medications such as Cetirizine and Desloratadine.
Which type of antihistamine should be used?
Second-generation antihistamines are generally recommended, although sometimes and in certain circumstances they may cause drowsiness similar to that caused by first-generation antihistamines. For example, if you have trouble sleeping because of itchy skin.
What forms are antihistamines available in?
Antihistamines are available as tablets, creams, or nasal sprays.
What are the main indications for using an antihistamine?
Allergic conditions that can benefit and improve from the use of antihistamines include:
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Allergic Rhinitis
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Atopic eczema
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Urticaria (hives)
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Allergic Conjunctivitis
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Allergic reactions resulting from insect bites and stings
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Allergic reactions to certain types of foods and drinks
Can I take antihistamines during pregnancy?
As a general rule, no medication should be taken during pregnancy unless there is a clear medical need. You should always check with your doctor before taking any medication. If your doctor believes there is a need to take them, the antihistamines considered safest during pregnancy are Chlorphenamine and Loratadine. Short-term medical trials suggest that Chlorphenamine is suitable for use during pregnancy. They should be prescribed only when absolutely necessary and avoided in the first trimester of pregnancy.
Who should not take antihistamines?
Caution should be exercised when using sedating antihistamines in the following cases:
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Benign Prostatic Hyperplasia and Urinary Retention
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Acute Glaucoma
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Epilepsy: Precautions should be taken when using it.
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Hepatic & Renal Impairment
What are the main side effects of antihistamines?
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Sedation: This is one of the problems associated with first-generation antihistamines, although it may also affect some patients taking second-generation ones.
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Dizziness tends to disappear over time.
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Less common side effects include: blurred vision, difficulty urinating, dry mouth, vomiting, constipation or diarrhea, skin or eye irritation (from preparations, creams, and eye drops).
