Antihistamines
Learn about antihistamines: uses, dosage, side effects, warnings, and how they relieve allergy symptoms and other conditions.
Overview
Antihistamines are medications that block the action of histamine, a chemical released by the immune system during allergic reactions. They are commonly used to treat allergies, hay fever, and hives, and some types are also effective for motion sickness, nausea, and as sleep aids. Antihistamines are generally classified as first-generation (which tend to cause drowsiness) and second-generation (which are less sedating).
Common Symptoms
- Drowsiness and reduced alertness (especially first-generation)
- Dry mouth, nose, or throat
- Dizziness or headache
- Blurred vision
- Digestive upset such as nausea or constipation
Possible Causes
- • Relief of seasonal and perennial allergy symptoms
- • Treatment of hay fever (allergic rhinitis)
- • Reduction of hives and skin itching
- • Management of motion sickness and nausea
- • Use as a short-term sleep aid for some first-generation types
Lifestyle Tips
Avoid driving or operating machinery if the medication causes drowsiness
Do not combine with alcohol or other sedating medications
Consult a doctor before use if you have glaucoma, enlarged prostate, or thyroid disease
Use with caution in older adults due to increased sensitivity
Inform your doctor of all medications to avoid interactions
Some antihistamines are not recommended during pregnancy or breastfeeding without medical advice
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