Diphenhist : Uses, Side Effects, Interactions & More
Why is this medication prescribed?
Diphenhist (Diphenhydramine) is used to relieve red, irritated, itchy, and watery eyes; sneezing and a runny nose caused by hay fever, allergies, or the common cold. Diphenhist is also used to relieve a cough caused by mild irritation of the throat or airways. Diphenhist is also used to prevent and treat motion sickness and to treat insomnia (difficulty falling or staying asleep). Diphenhist is also used to control abnormal movements in people who have early-stage parkinsonian syndrome (a disorder of the nervous system that causes difficulties with movement, muscle control, and balance) or who experience movement problems as a side effect of a medicine.
Diphenhist will relieve the symptoms of these conditions, but it will not treat the cause of the symptoms or speed recovery. Diphenhist should not be used to cause drowsiness in children. Diphenhist is in a class of medications called antihistamines. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms.
How should this medicine be used?
Diphenhist (Diphenhydramine) comes as a tablet, a rapidly disintegrating (dissolving) tablet, a capsule, a liquid-filled capsule, a dissolving strip, a powder, and a liquid to take by mouth. When Diphenhist is used for allergy, cold, and cough symptom relief, it is usually taken every 4 to 6 hours. When Diphenhist is used to treat motion sickness, it is usually taken 30 minutes before departure and, if necessary, before meals and at bedtime. When Diphenhist is used to treat insomnia, it is taken at bedtime (30 minutes before planned sleep). When Diphenhist is used to treat abnormal movements, it is usually taken three times a day at first and then taken 4 times a day. Carefully follow the instructions on the package or on your prescription label and ask your doctor or pharmacist to explain any part you do not understand. Take Diphenhist exactly as directed. Do not take more or less or take it more often than prescribed by your doctor or indicated on the label.
Diphenhist comes alone and in combination with pain relievers, fever reducers, and decongestants. Consult your doctor or pharmacist about which product is best for your symptoms. Check the labels on over-the-counter cough and cold products carefully before using two or more products at the same time. These products may contain the same active ingredients, and taking them together could cause you to overdose. This is especially important if you are giving a child cough and cold medicine.
Over-the-counter cough and cold products, including products that contain Diphenhist, can cause serious side effects or death in young children. Do not give these products to children under the age of 4. If you give these products to children ages 4-11, use caution and carefully follow package directions.
If you are giving Diphenhist or a combination product containing Diphenhist to a child, read the package label carefully to make sure it is the right product for a child of that age. Do not give Diphenhist products made for adults to children.
Before giving a Diphenhist product to a child, check the package label to find out how much of the medicine the child should receive. Give the dose that matches the child’s age in the table. Ask your child’s doctor if you don’t know how much medicine to give.
If you are drinking the liquid, do not use a homemade spoon to measure your dose. Use the measuring spoon or cup that comes with the medicine or use a specially made spoon to measure the medicine.
If you are taking the dissolving strips, put them on your tongue one by one and swallow them after they melt.
If you are taking the quick-dissolving tablets, put one tablet on your tongue and close your mouth. The tablet will dissolve quickly and can be swallowed with or without water.
If you are taking the capsules, swallow them whole. Do not try to break the capsules.
Other uses for this medicine
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking Diphenhist,
- Tell your doctor and pharmacist if you are allergic to Diphenhist, any other medications, or any of the ingredients in Diphenhist preparations. Ask your doctor or pharmacist or check the package label for a list of the ingredients.
- Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: other Diphenhist products (including those used on the skin); other medicines for colds, hay fever, or allergies; medications for anxiety, depression, or seizures; muscle relaxants; narcotic pain medications; sedative sleeping pills; and tranquilizers.
- Tell your doctor if you have or have ever had asthma, emphysema, chronic bronchitis, or other types of lung disease; glaucoma (a condition in which increased pressure in the eye can lead to gradual loss of vision); ulcers; difficulty urinating (due to an enlarged prostate); heart disease; hypertension; seizures or an overactive thyroid gland. If you are using the liquid, tell your doctor if you have been told to follow a low sodium diet.
- Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking Diphenhist, call your doctor.
- You should know that Diphenhist should generally not be used in older adults, except to control severe allergic reactions, because it is not as safe or effective as other medications for treating your condition. If you are 65 years or older, talk to your doctor about the risks and benefits of taking this medication.
- If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking Diphenhist.
- You should know that this medicine may make you drowsy. Do not drive a car or operate machinery until you know how this medicine affects you.
- Remember that alcohol can increase drowsiness caused by this medicine. Avoid alcoholic beverages while you are taking this medicine.
- If you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), you should know that some brands of chewable tablets and fast-disintegrating tablets that contain Diphenhist may be sweetened with aspartame, a source of phenylalanine.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
Diphenhist is generally taken as needed. If you have been told by your doctor to take Diphenhist regularly, take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Diphenhist may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- dry mouth, nose, and throat
- drowsiness
- dizziness
- nausea
- vomiting
- loss of appetite
- constipation
- increased chest congestion
- headache
- muscle weakness
- excitement (especially in children)
- nervousness
Some side effects may be serious. If you experience any of the following symptoms, call your doctor immediately:
- vision problems
- difficulty urinating or painful urination
Diphenhist can cause other side effects. Call your doctor if you experience any unusual problems while taking this medicine.
If you experience a serious side effect, you or your doctor can submit a report online to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medicine in its container, tightly closed and out of the reach of children. Store at room temperature and away from excess heat and moisture (not in the bathroom).
It is important to keep all medicines out of the sight and reach of children, since many containers (such as those containing weekly pills and those for eye drops, creams, patches and inhalers) are not child-resistant and small children can easily open them. To protect young children from poisoning, always close the safety caps and immediately place the medicine in a safe place, one that is upright and out of their sight and reach. http://www.upandaway.org
Unnecessary medications must be disposed of in special ways to ensure that pets, children, and others cannot consume them. However, you should not flush this medicine down the toilet. Instead, the best way to dispose of your medications is through a drug take-back program. Talk to your pharmacist or contact your local recycling / trash department to find out about take-back programs in your community. Check out the FDA drug safe disposal website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
In case of emergency/overdose
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim collapsed, had a seizure, is having trouble breathing, or cannot wake up, call 911 immediately.
What other information should I know?
Ask your pharmacist any questions you have about Diphenhist.
It is important that you keep a written list of all prescription and over-the-counter (over-the-counter) medications you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should take this list with you every time you visit a doctor or if you are admitted to a hospital. It is also important information to take with you in case of emergencies.
Brand Names
- Aler-Dryl®
- Allergia-C®
- Allermax®
- Altaryl®
- Banophen®
- Ben Tann®
- Benadryl®
- Bromanate AF®
- Compoz Nighttime Sleep Aid®
- Dicopanol®
- Diphedryl®
- Diphen®
- Diphenadryl®
- Diphenhist®
- Diphenylin®
- Dytan®
- Hydramine®
- Nytol®
- Pardryl®
- PediaCare Children’s Allergy®
- Siladryl®
- Silphen®
- Sominex®
- Unisom®
Disclaimer: We have made every effort to ensure that all information is factually accurate, comprehensive and up-to-date. However, this article should not be used as a licensed health care professional’s choice of knowledge and expertise. You should always consult your doctor or other health care professional before taking any medication. The information given here is subject to change and it has not been used to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions or adverse effects. The lack of warning or other information for any drug does not indicate that the combination of medicine or medication is safe, effective or appropriate for all patients or all specific uses.