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Antihistamine tablets (sedating)

Patient information A-Z


The following are some examples of brand names of sedating antihistamine tablets:

  • Chlorphenamine (Piriton® )
  • Hydroxyzine (Atarax® )

What are antihistamine tablets and what do they do?

Antihistamine tablets work to reduce itching which many people with kidney diseases find to be a problem, especially at night when they are trying to get to sleep.

Antihistamine tablets such as chlorphenamine are known as sedating antihistamines as they not only reduce itching but also make people drowsy which can be beneficial if the itching is leading to a loss of sleep.

How do I take my antihistamine tablet?

Chlorphenamine tablets (4mg) can be taken up to four times daily. Hydroxyzine tablets can also be taken up to four times daily.

Both tablets should be taken when needed but not exceeding the dose stated on the label.

Both chlorphenamine and hydroxyzine can cause drowsiness and so often patients find taking a dose at bedtime is beneficial if itching is a problem overnight and disturbs their sleep.

Are there any side effects?

The main adverse effects seen with antihistamine tablets include:

  • Drowsiness
  • Dry mouth
  • Blurred vision

These side effects should be mild but if you have any concerns about these or any other side effects please contact your doctor or specialist nurse for advice. If you are affected with drowsiness when taking these tablets you should avoid driving or operating heavy machinery.

Are there any problems taking antihistamine tablets with any other medications?

Antihistamine tablets such as chlorphenamine and hydroxyzine can make the effects of alcohol stronger (such as you may feel more sleepy than usual) and so you may feel drowsy if you drink alcohol when taking these tablets.

Other tablets which cause you to become sleepy such as sleeping tablets and some antidepressant tablets may also enhance the sedative effect of the antihistamine making you more drowsy than normal.

Only take tablets prescribed for you by your doctor and check with your pharmacist before taking any new medicines.

Further information

Further information about your tablet can be found in the patient information leaflet found in the tablet/capsule box or on the container.

If you have any other questions about your medication, please contact the medicine helpline on 01223 217502.

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Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

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Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151