Topic Overview

Oral
antihistamines are available without a prescription. Common types such as diphenhydramine (for example, Benadryl), chlorpheniramine (for example, Chlor-Trimeton), and loratadine (for example, Claritin) are used to treat
allergy symptoms and itching.

Look for generic or store brands,
which often cost less than name brands. For example, diphenhydramine is the
generic name for the brand name Benadryl.

Antihistamines that are
taken by mouth (oral) work better than those that are applied directly to the
skin (topical) because a pill or capsule contains a specific dose of medicine.
The dose in a cream or ointment depends on how much is applied at one time and
is harder to control. Too much antihistamine absorbed through the skin can be
toxic, especially to children. Don’t give any antihistamines to your child
unless you’ve checked with the doctor first. The use of cream or ointment
antihistamines is not reliable and not recommended.

Read and follow all instructions on the label. Be sure to
follow the
nonprescription medicine precautions.

Do
not take oral antihistamines when you are driving, are operating machinery, or need
to be alert because they can make you sleepy.

Use caution if you
have other health problems, such as glaucoma, epilepsy, or an enlarged
prostate. Antihistamines can cause your other health problems to get worse and
also may interact with other medicines, such as antidepressants, sedatives, and
tranquilizers. Read the package carefully, and ask your
pharmacist or doctor to help you choose
an antihistamine that will not cause problems.

Antihistamines are often combined with a decongestant in one product. These medicines may not be safe for young children or for people who have certain health problems. Read and follow all instructions on the label.

Side effects

  • In children:
    • Antihistamines may make young children
      sleepy or may stimulate the nervous system, causing hyperactivity. Don’t give
      antihistamines to your child unless you’ve checked with the doctor first.
    • In rare cases, diphenhydramine (especially forms of it that are
      applied to the skin) can cause severe side effects in children, such as
      hallucinations,
      tremors, and coma.
  • In older children and adults:
    • Antihistamines may cause
      drowsiness.
    • Weakness; blurred vision; dry nose, mouth, and throat;
      difficulty urinating; or stomach upset also can occur.

If you have side effects, stop taking the medicine and call
your doctor.

See Drug Reference for a full list of side effects.
(Drug Reference is not available in all systems.)

Credits

ByHealthwise Staff
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP – Emergency Medicine
Specialist Medical Reviewer Martin J. Gabica, MD – Family Medicine

Current as ofOctober 6, 2017