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Is it OK to take antihistamines every day?

Medically reviewed by Melisa Puckey, BPharm. Last updated on Aug 26, 2022.

Official answer


Yes, most people can take antihistamines every day, if they have daily symptoms of their allergies. The number of times you take an antihistamine each day depends on the type of antihistamine.

Some antihistamines are taken every 4 to 6 hours, and some are longer-lasting antihistamines that are taken every 12 to 24 hours.

Consult the drug label and ask your health care provider how long and how often you should take an antihistamine.

How to take Antihistamines:

Occasional use when you have symptoms:
When you have an allergy that you only have occasionally you can take the antihistamine just when needed, once you have the symptoms.

Occasional use to prevent symptoms when you know your allergy triggers.
This is when you know you are going to encounter something that sets off your allergies, so you take your antihistamines as a preventative before you are exposed to the allergan that triggers your allergy.

Regular use for chronic allergies
You may take an antihistamine every day to keep long-term allergy symptoms under control.

Types of antihistamines

Second-generation antihistamine.
If you take an antihistamine frequently or daily, your health care provider may recommend a second-generation antihistamine as they are less likely to cause side effects like sleepiness and fatigue. Example of second-generation antihistamine are:

Second-generation antihistamines may be used to treat long-term conditions such as:

  • Allergic rhinitis
  • Sinusitis
  • Atopic dermatitis
  • Chronic urticaria

First generation antihistamines
The effects of first-generation antihistamines—such as Benadryl (diphenhydramine) or Chlor-Trimeton (chlorpheniramine), among others— they may cause drowsiness or sedation so are often taken at night.
These first-generation antihistamines are often used for short periods to treat or prevent:

  • Common colds
  • Seasonal allergies
  • An allergic reaction
  • Motion sickness
  • Dizziness
  1. U.S. National Library of Medicine MedlinePlus. Antihistamines for allergies. May 2020. Available at: [Accessed September 4, 2021].
  2. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012. Antihistamines. [Updated 2017 Jan 16].

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