Antihistamine (By mouth)

Introduction

Treats hay fever and other allergies, motion sickness, nausea and vomiting, or other medical conditions.

Brand Name(s)

Ala-Hist IR, Alavert, Aldex AN, Aler-Dryl, All Day Allergy, Allegra, Allegra Allergy, Allegra ODT, Aller-Chlor, Aller-G-Time, Allergy, Allergy Relief, Allergy Relief Medicine, Allermax, Anti-Hist

When This Medicine Should Not Be Used

How to Use This Medicine

Liquid, Tablet, Long Acting Tablet, Dissolving Tablet, Fizzy Tablet, Chewable Tablet, Capsule, Liquid Filled Capsule, Long Acting Capsule

  • Take your medicine as directed.
  • Follow the instructions on the medicine label if you are using this medicine without a prescription.
  • Drink plenty of fluids.
  • You may take this medicine with food to lessen stomach upset.
  • Swallow the extended-release tablet, extended-release capsule, or liquid-filled capsule whole. Do not crush, chew, or break it.
  • The chewable tablet must be chewed completely before you swallow it.
  • Make sure your hands are dry before you handle the disintegrating tablet. Peel back the foil from the blister pack, then remove the tablet. Do not push the tablet through the foil. Place the tablet in your mouth. After it has melted, swallow or take a drink of water.
  • Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup. You might need to shake the medicine before using it.

If a dose is missed:

  • May be taken as soon as possible.
  • Skip the missed dose if it is almost time for your next dose.
  • You should not use two doses at the same time.

How to Store and Dispose of This Medicine

  • Store at room temperature, away from heat, direct light, and moisture. Do not freeze.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Avoid drinking alcohol while taking this medicine.
  • Avoid taking this medicine with other antihistamines.
  • Make sure your doctor knows if you are taking any medicine that makes you sleepy, such as sedatives, narcotic pain killers, or antidepressants while you are receiving this medicine.

Warnings While Using This Medicine

  • Ask your doctor before taking this medicine if you are pregnant or breastfeeding, or if you have glaucoma or trouble urinating.
  • This medicine might contain phenylalanine. This is only a concern if you have a disorder called phenylketonuria (a problem with amino acids). Talk to your doctor before using this medicine.
  • Side effects of this medicine may occur more frequently in young children and older adults.
  • Some antihistamine syrups contain alcohol.
  • This medicine may cause drowsiness. If it does, avoid driving a car or using machinery.
  • This medicine may cause a skin rash when you are out in the sun. Use a sunscreen when you are outside, and try not to spend long periods in direct sunlight.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Severe drowsiness, clumsiness, or confusion
  • Faintness
  • Fast heartbeat
  • Shortness of breath or trouble breathing

If you notice these less serious side effects, talk with your doctor:

  • Drowsiness or dizziness
  • Upset stomach
  • Reduced appetite
  • Irritability or excitement
  • Nervousness
  • Changes in vision, such as trouble focusing

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 7/4/2015

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