Benadryl Side Effects

Benadryl is a common drug used in relieving the symptoms of allergies. The symptoms include sneezing, runny nose and coughing. You can also purchase topical Benadryl for the relief of rashes. Products like Benadryl, including generic brands with the same ingredients, are available from various companies that may have different dosages and capsule/tablet sizes. Be sure to read all instructions before you use Benadryl.


When Benadryl is dosed, it is typically done in tablets. There are also liquid and chewable versions of this drug available. The dose size is largely based on how much the patient weighs.

You can take Benadryl without drinking or eating, but sometimes this can lead to stomach ache. Take your dose with something to eat or drink, if you can. Benadryl was not developed to be used all the time. Speak with your physician if you plan to take the drug on a regular basis, to find the safest dosage you can use. You should never take any more than one dose for every 4-6 hours.

Benadryl Dosing Information

BENADRYL® Allergy Tablets

These can be taken by anyone older than 12 years of age. Take 1-2 tablets every four to six hours or as your physician directs. For children ages 6 to 12, take just one tablet every four to six hours or as direction by your physician. Do not use for children under six years of age.


These can also be taken in regular dosage by adults and children older than 12 years. Take one – two capsules every four to six hours, or as your physician directed you. Children ages 6 to 12 can take one capsule every four to six hours or as their physician directs. Liqui-Gels cannot be given to children under the age of six.

Children’s BENADRYL® Allergy Liquid

This formula was developed for children between the ages of six and 11. Give them one to two teaspoons every four to six hours unless directed differently by their pediatrician. Do not use in children five years of age or younger.

Benadryl’s most Common Side Effects

Drowsiness is the most common side effect of Benadryl. One percent or more of patients who use Benadryl have reported drowsiness. This does not USUALLY interfere with the patient’s ability to drove or work, but it can. Make sure that you don’t drive or operate machinery after taking Benadryl, if you’ve not taken it often before. Benadryl can cause you to lose your focus or cause issues that could affect your daily activities.

Heartburn is also a common Benadryl side effect. About one percent of patients who take Benadryl experience this. It may include indigestion, though this is usually mild. You can eliminate or relieve heartburn if you eat food when you take Benadryl. As your system adjusts to Benadryl if you take it frequently, the heartburn usually will become less frequent.

Treating allergies with Benadryl may lead to dryness in your throat, nose and mouth. It dries up the mucus in your body, and your sinuses. This does not occur every time someone uses the product, but it is fairly common.

Be sure to drink lots of liquids when you’re taking Benadryl. Remaining well-hydrated will help your body to get rid of excess mucus that contributes to your symptoms. You can chew gum or candy or suck on ice cubes if you like, for relief from the dryness in the mouth.

Rare Benadryl Side Effects

Some patients may have allergic reactions to this medication. They include itchiness or rashes. You may also develop hives from a reaction to Benadryl. Some people who have reactions to Benadryl have even experienced difficulty in breathing or chest tightening. This is usually caused by facial or throat swelling. This puts undue pressure on your airway. If you experience any of these symptoms, stop using Benadryl and call your physician or emergency care clinic.

Some users of Benadryl may experience loss of appetite, nausea or vomiting. If you take Benadryl regularly, you are more likely to experience these side effects. You may also develop constipation from antihistamines. These side effects are usually minor, but if you have a serious reaction, speak to your physician about a dosage adjustment.

If you become severely fatigued from Benadryl, you may become nervous, restless, shaky or irritable. You may also experience room spinning or disorientation. If you experience these side effects, don’t drive or use machinery.

If you take Benadryl regularly, your body may develop a tolerance to it. This takes time, though. Speak to your physician if you have a serious reaction, or one that limits your ability to properly function. They may choose an alternate medicine for you to take.

Side Effects in Seniors, Children and Pregnant Women

Infants and very young kids shouldn’t be given Benadryl. Their bodies cannot yet handle the side effects and reactions that could occur. If your child ingests the medicine accidentally, immediately call a poison control hotline.

Pregnant women should only use Benadryl with a physician’s supervision, and it should be taken sparingly. However, no studies have found significant fetal damage caused by the use of Benadryl. It may not work without incident with any other medications you might take during pregnancy, though.

Seniors can use Benadryl safely, although the side effects may be more serious for them. If you’re a senior, consult your physician before you start taking Benadryl. If seniors have conditions like heart problems or ulcers, these can become worse when taking Benadryl. People with liver issues should speak to their physicians to determine the best dosage for them.

Benadryl Interactions with other Substances & Medicines

Never use Benadryl if you’re drinking alcohol. The drowsiness and dizziness that are already common Benadryl side effects are worsened with alcohol.

You can take Benadryl with many other medicine types, as long as they’re not also antihistamines. If you take tranquilizers, they may increase your drowsiness. Nausea may mask a more serious condition you may have. Speak to your physician about any medications you take or any underlying conditions you have.

If you take Benadryl for a long time period, you could become chemically dependent on it. Don’t take it for 10 days in a row or more without physician supervision. If you’ve taken Benadryl for a long time and it hasn’t improved your allergy symptoms, seek out medical attention.


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