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Benadryl Injection

Last reviewed on RxList: 1/11/2017

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Benadryl Injection Overview & Usage

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

DIPHENHYDRAMINE - INJECTION

(dye-fen-HI-druh-meen)

COMMON BRAND NAME(S): Benadryl

USES: Diphenhydramine injection is an antihistamine used to treat life-threatening allergic reactions (anaphylaxis) along with epinephrine and other treatments. It is also used to relieve symptoms of household allergies, hay fever and the common cold when medication cannot be given by mouth. Common allergy symptoms relieved by antihistamines include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose and sneezing.

It is also used to treat nausea, vomiting and dizziness caused by motion sickness when medication cannot be given by mouth. Diphenhydramine 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).

Diphenhydramine should not be used in newborns or premature infants because of an increased risk of side effects.

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

Diphenhydramine injection is also used alone or with other medications to treat shaking (tremor) and muscle stiffness caused by Parkinson's disease when medication cannot be given by mouth. It may also be used to treat side effects of certain psychiatric drugs such as involuntary movements and muscle stiffness (e.g., EPS). It works by blocking acetylcholine. (See also Uses section.)

HOW TO USE: This medication is injected into a vein (IV) no faster than 25 milligrams per minute, or deeply into a muscle as directed by your doctor. Be very careful to inject into a vein or muscle and not into the skin or just under the skin. If this medication is injected into or just under the skin, it can destroy the skin and tissues around the injection site (necrosis).

If you are giving this medication to yourself at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.

Do not use this medication more often than prescribed. Your dosage is based on your medical condition and response to therapy. Inform your doctor if your condition does not improve or if it worsens.

Benadryl Injection Side Effects & Precautions
SIDE EFFECTS: Drowsiness, dizziness, headache, irritability, stomach upset, vision changes (e.g., blurred vision), decreased coordination, constipation, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If they persist or become bothersome, inform your doctor.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute. Diphenhydramine can dry up and thicken the mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, be sure to drink plenty of fluids unless otherwise directed by your physician.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication 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), pounding/irregular heartbeat, ringing in the ears, seizure, difficulty urinating.

A very serious allergic reaction to this drug is unlikely, but get medical help right away if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

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

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the Benadryl Injection (diphenhydramine injection) Side Effects Center for a complete guide to possible side effects

PRECAUTIONS: Before using diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or to dimenhydrinate; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (e.g., asthma, emphysema), glaucoma, heart problems, high blood pressure, liver disease, mental/mood disorders, seizures, stomach problems (e.g., ulcers, obstruction), overactive thyroid, difficulty urinating (e.g., enlarged prostate, urinary retention).

This drug 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. Limit the use of alcohol and certain other medications that cause drowsiness. (See also Drug Interactions.)

To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position.

Caution is advised when using this drug in children because they are more sensitive to the effects of antihistamines. This drug can often cause excitement in young children instead of drowsiness.

Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, low blood pressure, confusion, constipation, or trouble urinating. Drowsiness, dizziness, and confusion can increase the risk of falling.

This medication should be used only when clearly needed during pregnancy. Tell your doctor if you are pregnant before using this medication.

This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

Benadryl Injection Missed Dose
SIDE EFFECTS: Drowsiness, dizziness, headache, irritability, stomach upset, vision changes (e.g., blurred vision), decreased coordination, constipation, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If they persist or become bothersome, inform your doctor.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute. Diphenhydramine can dry up and thicken the mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, be sure to drink plenty of fluids unless otherwise directed by your physician.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication 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), pounding/irregular heartbeat, ringing in the ears, seizure, difficulty urinating.

A very serious allergic reaction to this drug is unlikely, but get medical help right away if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

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

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the Benadryl Injection (diphenhydramine injection) Side Effects Center for a complete guide to possible side effects

PRECAUTIONS: Before using diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or to dimenhydrinate; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (e.g., asthma, emphysema), glaucoma, heart problems, high blood pressure, liver disease, mental/mood disorders, seizures, stomach problems (e.g., ulcers, obstruction), overactive thyroid, difficulty urinating (e.g., enlarged prostate, urinary retention).

This drug 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. Limit the use of alcohol and certain other medications that cause drowsiness. (See also Drug Interactions.)

To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position.

Caution is advised when using this drug in children because they are more sensitive to the effects of antihistamines. This drug can often cause excitement in young children instead of drowsiness.

Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, low blood pressure, confusion, constipation, or trouble urinating. Drowsiness, dizziness, and confusion can increase the risk of falling.

This medication should be used only when clearly needed during pregnancy. Tell your doctor if you are pregnant before using this medication.

This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

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