Antihistamines - Interactions

Authored by Dr Mary Harding, 05 Jul 2017

Patient is a certified member of
The Information Standard

Reviewed by:
Dr Helen Huins, 05 Jul 2017

Alcohol interacts with antihistamines. Probably the effect is greater for the sedative antihistamines, but it can occur with either type. Alcohol and an antihistamine in combination are more likely to make you feel sleepy than either on its own. So the answer is be wary and don't overdo it!

Some medicines may interact with antihistamines, increasing the side-effects of either or both medicines. Usually it is better to avoid taking antihistamines at the same time as certain medicines, including:

  • Certain types of antidepressants. Tricyclic antidepressants such as amitriptyline and lofepramine may interact with antihistamines. Other antidepressants such as moclobemide.
  • Antacids, which may interfere with the way the antihistamine is absorbed, thus making it less effective.
  • Other tablets which make you drowsy, as the combination may be too much. For example opioid painkillers or benzodiazepines and Z drugs.
  • A group of medicines called antimuscarinics. This includes medicines such as hyoscine, oxybutynin, propantheline and tolterodine. Because these medicines can give you similar side-effects, such as a dry mouth or problems passing urine, the combination may make the side-effects more serious.

If you are buying your antihistamine from a pharmacy, make sure you tell the pharmacist if you take other medicines so they can advise accordingly.

Also watch the ingredients in other over-the-counter treatments. For example, remedies for coughs and colds may contain antihistamines, in which case you might end up taking double the dose by mistake.

Further reading and references

I get an awful itch on the top of my mouth near the back...i find myslef subconsciously itching this day and night. It does get better with half ever tablets sometimes but comes back and it comes at...

sara89022
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