• Benadryl is an antihistamine used to relieve symptoms of allergy, hay fever and the common cold. Diphenhydramine is used to treat sneezing, coughing, runny nose, itching, watery eyes, hives, rashes, itching and other symptoms of allergies and the common cold.

How should you take this medication?

• Take each dose with a full glass of water.
   
• Diphenhydramine can be taken with or without food. Diphenhydramine may be taken with food or milk if stomach upset occurs. Measure the liquid medication with a dose-measuring spoon or device, not a regular teaspoon, to make sure you have the correct dose.
   
• 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.
   
• For adults and children 12 years and older, the usual dosage is 1 tablet or caplet every 4 to 6 hours. Do not take more than 4 tablets or caplets each 24 hours. For children under 12 consult a doctor.
   
• Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose.
   

General Precautions with Diphenhydramine

• Before taking diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.
   
• Use caution when driving, operating machinery, or performing other hazardous activities. Diphenhydramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
   
• The rapidly-dissolving and chewable preparations of this product may contain aspartame. If you have phenylketonuria or any other condition that requires you to restrict your intake of aspartame, consult your doctor or pharmacist regarding the safe use of this medicine.
   
• Do not give this medication to a child younger than six years of age unless directed to do so by a doctor. Caution is advised when using this drug in children because they are more sensitive to the effects of antihistamines.
   
• Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while taking diphenhydramine.

What are the possible side effects of Diphenhydramine?

• Stop taking diphenhydramine and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).
   
• Drowsiness, dizziness, headache, constipation, stomach upset, vision changes, irritability, decreased coordination, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication.
   
• To relieve dry mouth, suck on hard candy or ice chips, drink water or use a saliva substitute. Diphenhydramine can dry up and thicken mucus in your lungs, making it more difficult to breathe and clear your lungs.