Benadryl General Information
Benadryl is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose, and sneezing. It is also used to prevent and treat nausea, vomiting and dizziness caused by motion sickness. Benadryl can also be used to help you relax and fall asleep.
Benadryl works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine).
Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Therefore, do not use Benadryl to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.
These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use Benadryl to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).
OTHER USES: This section contains uses of Benadryl that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use Benadryl for a condition that is listed in this section only if it has been so prescribed by your health care professional.
Benadryl is also used alone or with other medications to treat shaking (tremor) and muscle stiffness caused by Parkinson's disease. It may also be used to treat side effects of certain psychiatric drugs such as involuntary movements and muscle stiffness (such as EPS). It works by blocking acetylcholine (See also Uses section).
How to Use Benadryl
Follow all directions on the product package. If your doctor has prescribed Benadryl, take it as directed. If you are uncertain about any of the information, consult your doctor or pharmacist.
Take the tablet, capsule, or liquid form by mouth with or without food. Measure liquid forms of Benadryl using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If you have a single-dose form of Benadryl (such as a single-use whistle), you do not need to measure the dose.
The rapidly-dissolving tablet or strip should be allowed to dissolve on the tongue and then swallowed, with or without water. The chewable tablets should be chewed thoroughly before being swallowed.
The dosage is based on your age, medical condition, and response to treatment. There are many brands and forms of Benadryl available. Read the dosing instructions carefully for each product because the amount of Benadryl may be different between products. Do not increase your dose or take Benadryl more often than directed.
To prevent motion sickness, take your dose 30 minutes before starting activity such as travel. To help you sleep, take your dose about 30 minutes before bedtime. If you continue to have difficulty sleeping for longer than 2 weeks, contact your doctor.
Tell your doctor if your condition does not improve or if it worsens.
Benadryl Possible Side Effects
Drowsiness, dizziness, constipation, stomach upset, blurred vision, or dry mouth/nose/throat may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.
If your doctor has directed you to use Benadryl, remember that he or she has judged that the benefit to you is greater than the risk of side effects. Many people using Benadryl do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as restlessness, confusion), difficulty urinating, fast/irregular heartbeat.
Get medical help right away if you have any very serious side effects, including: seizures.
A very serious allergic reaction to Benadryl is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
Benadryl Precautions
Before taking Benadryl, tell your doctor or pharmacist if you are allergic to it; or to dimenhydrinate; or if you have any other allergies. Benadryl may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using Benadryl, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as asthma, emphysema), high pressure in the eye (glaucoma), heart problems, high blood pressure, liver disease, seizures, stomach/intestine problems (such as ulcers, blockage), overactive thyroid (hyperthyroidism), difficulty urinating (for example, due to enlarged prostate).
Benadryl may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Avoid alcoholic beverages.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Liquid products, chewable tablets, or dissolving tablets/strips may contain sugar and/or aspartame. Liquid products may also contain alcohol. Caution is advised if you have diabetes, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using Benadryl safely.
Children may be more sensitive to the side effects of Benadryl. Benadryl can often cause excitement in young children instead of drowsiness.
Older adults may be more sensitive to the side effects of Benadryl, especially drowsiness, dizziness, confusion, constipation, or trouble urinating. Drowsiness, dizziness, and confusion can increase the risk of falling.
During pregnancy, Benadryl should be used only when clearly needed. Discuss the risks and benefits with your doctor.
Benadryl passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.
Benadryl Possible Intercations
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with Benadryl include: antihistamines applied to the skin (such as Benadryl cream, ointment, spray).
Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, other antihistamines (such as chlorpheniramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine).
Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
Benadryl may interfere with certain laboratory tests (including allergy skin test), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use Benadryl.