What Are Antihistamines?
Antihistamines are medications that help relieve allergy symptoms by blocking histamine, a chemical your body produces during allergic reactions.
Types of Antihistamines
First-Generation (Older)
-
Examples:
- Diphenhydramine (Benadryl)
- Chlorpheniramine
-
Characteristics:
- Cause drowsiness
- Work quickly
- Last 4-6 hours
Second-Generation (Newer)
-
Examples:
- Cetirizine (Zyrtec)
- Loratadine (Claritin)
- Fexofenadine (Allegra)
-
Characteristics:
- Less sedating
- Last 24 hours
- Fewer side effects
Common Uses
- Seasonal allergies
- Hay fever
- Hives
- Pet allergies
- Dust allergies
- Mild allergic reactions
Side Effects
Common Side Effects
- Drowsiness (especially with first-generation)
- Dry mouth
- Blurred vision
- Constipation
When to Seek Medical Attention
- Severe dizziness
- Rapid heartbeat
- Difficulty urinating
- Confusion
Usage Guidelines
- Follow prescribed dosage
- Take at the same time daily for best results
- Avoid alcohol while taking antihistamines
- Don't operate heavy machinery if experiencing drowsiness
Special Considerations
Drug Interactions
- Inform your doctor about other medications
- Avoid combining with sedatives
- Use caution with antidepressants
Not Recommended For
- Some chronic health conditions
- Pregnancy (consult doctor)
- Young children (age restrictions vary)
When to Contact Your Healthcare Provider
- Symptoms don't improve
- Side effects are severe
- Allergic reaction to the medication
- Questions about long-term use