Side Effects and Risks of Benadryl


Benadryl (diphenhydramine) is a common antihistamine medication used to treat allergies, rashes, and colds.

It comes in pills, capsules, liquids, and topical creams. It can be purchased over-the-counter or prescribed by your doctor.

Benadryl is generally considered safe and effective for most people when used as directed. However, there are some side effects and risks to be aware of.

Mild Side Effects

The most common side effects of Benadryl are relatively mild and don’t require medical attention. They include:

  • tiredness and sleepiness
  • headache
  • dry mouth
  • dry eyes
  • blurry vision
  • constipation
  • low blood pressure
  • dizziness

Many of these side effects are associated with the way Benadryl dries out your body and mucous membranes. To help reduce these side effects, drink plenty of fluids.

Older adults may be more susceptible to adverse side effects due to the slower rate at which their bodies process and eliminate the drug. The sleepiness and dizziness side effects can be hazardous for older adults, as they may increase the risk of falling.

Always read and follow the instructions carefully. Avoid operating heavy machinery or driving while you’re taking Benadryl.

Serious Side Effects

Although less common, some people may experience more severe side effects after taking Benadryl. If you experience any of the following side effects, stop taking Benadryl and call your doctor right away:

  • fast heartbeat
  • chest pain
  • heart rhythm problems
  • change in blood cell levels
  • confusion
  • memory loss
  • hallucinations
  • seizures
  • allergic reaction

These side effects are rare but can be very serious. If you experience any of them, it’s essential to seek medical attention.

Children under the age of 6 should not be given Benadryl, as side effects are more common and can be much more severe.

Other Risks Associated With Benadryl

Benadryl is intended to be a short-term solution for allergy symptoms. Taking it for long periods can lead to other problems, such as:

  • memory loss
  • dementia
  • anxiety
  • depression
  • psychosis

If you need treatment for an extended period, ask your doctor about other safer medications for long-term use.

Higher doses of Benadryl increase the risk of adverse side effects and can be life-threatening. Do not take more than the recommended dose or use more often than directed.

Benadryl is not recommended for people with certain medical conditions, such as:

  • history of allergic reaction to Benadryl
  • asthma or other respiratory conditions
  • dementia
  • heart problems
  • high blood pressure
  • kidney problems
  • liver problems

Do not drink alcohol while taking Benadryl. Alcohol can increase your risk of adverse side effects.