Benadryl (diphenhydramine)

Benadryl (diphenhydramine) is a brand-name, over-the-counter medication that’s classified as an antihistamine. It’s used to help relieve symptoms of hay fever (seasonal allergies), other allergies, and the common cold, as well as itchy skin due to insect bites, hives, and other causes.

Benadryl is effective for decreasing itchy skin from hives. It’s often considered a first-choice treatment for hives. But although it’s effective for decreasing symptoms of seasonal allergies, Benadryl isn’t often used for this purpose. This is due to side effects such as sleepiness.

Benadryl comes in many different forms. Some are oral (taken by mouth), and some are topical (applied to the skin). Examples include:

• oral tablets
• oral liquid-filled capsules (liqui-gels)
• oral chewable tablets
• oral liquid solution
• topical cream
• topical gel
• topical spray
• topical stick

Benadryl is available in generic forms, which are often store-brand products. The generic name of Benadryl is diphenhydramine. There are many different Benadryl-branded products. Some of these products contain just one ingredient, while others contain two ingredients. Examples of different Benadryl products and their ingredients include:

• Benadryl Allergy. This product contains one active ingredient, diphenhydramine, which is an antihistamine.
• Benadryl Allergy Plus Congestion. This product contains two active ingredients:
  • diphenhydramine, an antihistamine
  • phenylephrine, a decongestant
  • the type of condition you’re using Benadryl to treat
  • your age
  • the form of Benadryl you’re takingBenadryl Itch Stopping Cream. This product contains two active ingredients:
    • • diphenhydramine, an antihistamine
      • zinc, a skin protectant
    • Benadryl Itch Cooling Gel. This product doesn’t contain the usual antihistamine, diphenhydramine. It only contains camphor, which is a type of pain reliever that’s applied to the skin.

    When people say the name “Benadryl,” they usually mean the products that contain diphenhydramine. Because ingredients vary from one Benadryl product another, be sure to read the label closely before buying or using a Benadryl product. That way you’ll know what ingredients it contains. Benadryl dosage will depend on several factors. These include:

  • Typical dosage for adults: 25 to 50 mg, every 4 to 6 hours.

    Benadryl can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking Benadryl. This list doesn’t include all possible side effects.

    For more information on the possible side effects of Benadryl or tips on how to deal with a troubling side effect, talk with your doctor or pharmacist.

    More common side effects

    The more common side effects of Benadryl include:

    • sleepiness
    • dry mouth
    • weakness
    • dizziness
    • headache

    Some of these side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

    Serious side effects

    Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

    • decreased memory
    • impaired thinking
    • dementia
    • confusion
    • fast heartbeat
    • seizures

    Long-term side effects

    Over-the-counter Benadryl is approved for temporary or short-term use and isn’t intended for long-term use. There is very little scientific research about the long-term effects of Benadryl.

    Some side effects that may occur with long-term use include:

    • constipation
    • blurred vision
    • memory problems and dementia (especially in seniors)
    • anxiety
    • dependence

    Talk to your doctor about how often you have allergy symptoms. If you have symptoms frequently (more often than about four days per week), there may be a safer, more effective medication for you than Benadryl.