What kinds of antihistamines should be used to treat allergies?
There are 2 types of antihistamines available in Australia:
- First-generation (sedating) antihistamines often cause sleepiness. Examples of sedating antihistamines include Phenergan® and Polaramine®.
- Second-generation (less sedating or non-sedating) antihistamines that usually do not cause sleepiness. Examples include Claratyne®, Desonex®, Telfast® and Zyrtec®.
Antihistamines available in Australia
| Examples of less or non-sedating antihistamines Active ingredient and example brand | Examples of sedating antihistamines Active ingredient and example brand |
| Cetirizine (eg: Zyrtec®) | Dexchlorpheniramine (eg: Polaramine®) |
| Desloratadine (eg: Desonex®) | Promethazine (eg: Phenergan®) |
| Fexofenadine (eg: Telfast®) | |
| Loratadine (eg: Claratyne®) |
Antihistamines for allergic reactions
It is recommended that sedating antihistamines should not be used to treat allergic reactions. Sedating antihistamines can make people drowsy (sleepy) which makes it hard to know whether the person is drowsy because of the antihistamine or because of a drop in blood pressure due to a severe allergic reaction (anaphylaxis).
Less sedating or non-sedating antihistamines are recommended to manage signs and symptoms of mild to moderate allergic reactions, such as hives, welts or body redness, swelling of the face, lips, eyes, tingling of the mouth.
Antihistamines (sedating or non-sedating) DO NOT prevent or treat severe allergic reactions (anaphylaxis), which involves the following signs and symptoms: difficult or noisy breathing, swelling of tongue, swelling or tightness in throat, wheeze or persistent cough, difficulty talking or hoarse voice, persistent dizziness or collapse and pale and floppy (young children).
Anaphylaxis must be treated promptly with adrenaline (epinephrine) using an adrenaline injector, such as an EpiPen® or Anapen®, following instructions on the ASCIA Action Plan for Anaphylaxis.
Age recommendations for type of antihistamine
First-generation sedating antihistamines – Since 1 September 2020, all over-the-counter first-generation sedating antihistamines have been required to carry the warning ‘Do not give to children under 2 years of age’. The Therapeutic Goods Administration (TGA) has updated its advice for promethazine hydrochloride, sold as Phenergan® and other generic brands in November 2024
A MEDICATION SAFETY ALERT states that promethazine hydrochloride (Phenergan®) should not be used in children under six years of age as it has been found to cause a range of side effects such as hyperactivity, aggression and hallucination.
Second generation less or non-sedating antihistamines – Some of the less or non-sedating antihistamines are registered for use in infants 6 months and older, whilst others can be used from 12 months of age.
Always read the label and talk with your pharmacist or doctor about the right antihistamine for you or your child.
Antihistamines are available in different forms: tablet, liquid or chewable tablet.
Tablet
- Designed to be swallowed
- Easy to carry and pack in medicine kits
For people who are unable to swallow a tablet due to their age, medical condition or a disability, antihistamines that come as a liquid or chewable tablet form could be considered. Both liquid and chewable antihistamines work effectively.
Chewable tablets
- Made to be chewed and don’t require water to swallow them
- Easy to carry and pack in medicine kits
- Available for children over 2 years of age
- Worth checking that your family member is able to chew the tablet before relying on it during an allergic reaction.
Liquid antihistamine
- Liquid is easy to swallow
- Taste varies depending on brand and flavour
- More difficult to carry as the bottle is bulky and there is a risk of leakage
You may wish to have the liquid at home and the chewable tablets when out and about if your child is old enough for the chewable tablets.
Ask your pharmacist or doctor about the best choice of antihistamine for you or your family member.
More about allergy treatments
Related information
Types of allergies
Learn more about the different types of allergic disease including diagnosis, triggers and treatments and about allergic reactions.
Living with allergies
Learn more about daily life with allergies – including reading labels and ingredients, managing different environments and what to do if you or a loved one has an an allergic reaction.