Why is this drug prescribed?

Benadryl is an antihistamine with drying and sedative effects. It relieves red, inflamed eyes caused by food allergies and the itching, swelling, and redness from hives and other rashes that are caused by mild allergic reactions. It also relieves the sneezing, coughing, runny or stuffy nose, and red, teary, itching eyes caused by seasonal allergies (hay fever) and the common cold. Antihistamines work by decreasing the effects of histamine, a chemical released in the body that narrows air passages in the lungs and contributes to inflammation. Antihistamines reduce itching and swelling and dry up secretions from the nose, eyes, and throat.

Benadryl is also used to treat allergic reactions to blood transfusions, to prevent and treat motion sickness, and, with other drugs, to treat anaphylactic shock (severe allergic reaction) and Parkinson's disease, a nerve disorder characterized by tremors, stooped posture, shuffling walk, muscle weakness, drooling, and emotional instability.

Most important fact about this drug

Antihistamines may produce excitability in children. In the elderly they may cause dizziness, excessive calm, or low blood pressure.

How should you take this medication?

Benadryl should be taken exactly as prescribed, or follow instructions on the label.

--If you miss a dose...

Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.

--Storage instructions...

Store at room temperature. Protect from moisture.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Benadryl.

• More common side effects may include:
  Disturbed coordination, dizziness, excessive calm, increased chest congestion, sleepiness, stomach upset

• Less common or rare side effects may include:
  Anaphylactic shock (extreme allergic reaction), anemia, blurred vision, chills, confusion, constipation, convulsions, diarrhea, difficulty sleeping, double vision, dry mouth, nose, throat, early menstruation, excessive perspiration, excitation, fast, fluttery heartbeat, fatigue, frequent or difficult urination, headache, hives, inability to urinate, increased sensitivity to light, irregular heartbeat, irritability, loss of appetite, low blood pressure, nausea, nervousness, rapid heartbeat, rash, restlessness, ringing in the ears, stuffy nose, tightness of chest and wheezing, tingling or pins and needles, tremor, unreal or exaggerated sense of well-being, vertigo, vomiting

Why should this drug not be prescribed?

Benadryl should not be used in newborn or premature infants, or if you are breastfeeding your infant.

Do not take this medication if you are sensitive to or have ever had an allergic reaction to diphenhydramine hydrochloride or other antihistamines.

Special warnings about this medication

In general, you should use antihistamines very cautiously if you have the eye condition called narrow-angle glaucoma, narrowing of the stomach or intestine because of peptic ulcer or other stomach problems, intestinal blockage, symptoms of an enlarged prostate, or difficulty urinating due to obstruction in the bladder.

Antihistamines can make adults and children less alert and, in young children, may cause excitability.

Elderly people (60 years or older) are more likely to experience dizziness, extreme calm, and low blood pressure.

Use Benadryl cautiously if you have a history of asthma or other chronic lung disease, an over-active thyroid, high blood pressure, or heart disease.

This medication can cause drowsiness. Driving or operating dangerous machinery or participating in any hazardous activity that requires full mental alertness is not recommended until you know how you react to Benadryl.

Possible food and drug interactions when taking this medication

Benadryl may increase the effects of alcohol, and alcohol may increase the sedative effects of Benadryl. Do not drink alcohol while taking this medication.

If Benadryl is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Benadryl with the following:

Antidepressant drugs known as MAO inhibitors, such as Parnate and Nardil
Sedative/hypnotics such as Halcion, Nembutal, and Seconal
Tranquilizers such as Xanax and Valium

Special information if you are pregnant or breastfeeding

The effects of Benadryl during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. Benadryl should be used during pregnancy only if clearly needed. Antihistamine therapy is not advised for nursing mothers. If this medication is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment with Benadryl is finished.

Recommended dosage

Your doctor will tailor the dosage to suit your needs. Benadryl reaches its peak effect in 1 hour, and 1 dose will continue to work for 4 to 6 hours.

ADULTS

Motion Sickness

For prevention of motion sickness, take the first dose 30 minutes before exposure to motion; take the other doses before meals and at bedtime for as long as the motion continues.

CHILDREN (OVER 20 POUNDS)

This medication should not be used as a sleep aid for children under age 12.

Your physician will determine the best use of the drug in response to its effects on the child.

Overdosage

Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately. Antihistamine overdose has caused hallucinations, convulsions, and death in children.

• Symptoms of Benadryl overdose may include:
  Central nervous system depression or stimulation, especially in children, dry mouth, fixed, dilated pupils, flushing, stomach and intestinal symptoms