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diphenhydramine
Used for Allergic Conjunctivitis, Allergic Rhinitis, Anaphylaxis, Insomnia, Motion Sickness, Parkinson's Disease
Used for Allergic Conjunctivitis, Allergic Rhinitis, Anaphylaxis, Insomnia, Motion Sickness, Parkinson's Disease
Diphenhydramine, also known by the brand name Benadryl, is an over-the-counter antihistamine used to relieve allergy or common cold symptoms in adults and children. It comes as pills and a liquid and is typically taken by mouth every 4 to 6 hours as needed. Because it can make you drowsy, some people also use it as a sleep aid at bedtime. Common side effects include sleepiness, dizziness, and dry mouth.
What is Diphenhydramine?
What is Diphenhydramine used for?
- Short-term relief of allergy or common cold symptoms (runny nose, sneezing, itchy nose or throat, and itchy or watery eyes) - people 6 years and older
- Occasional trouble sleeping - people 12 years and older
How Diphenhydramine works
Diphenhydramine is an antihistamine. It works by blocking histamine, a chemical in your body that causes allergy and common cold symptoms like itching, sneezing, and runny nose.
Because diphenhydramine can enter the brain, it can also make you feel sleepy. That’s why it often causes drowsiness and is sometimes used as a short-term sleep aid.
When does Diphenhydramine start working?Time passed since treatment started:
Drug facts
| Common Brands | Benadryl, Unisom |
|---|---|
| Drug Class | Antihistamine |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Over-the-counter |
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Side effects of Diphenhydramine
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Sleepiness
- Dizziness
- Constipation
- Blurry vision
- Dry mouth
Less Common Side Effects
- Headache
- Stomach upset
- Trouble urinating
- Weakness
- Hyperactivity (more common in children)
Diphenhydramine serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Excessive sleepiness or dizziness
When do Diphenhydramine possible side effects begin and end?
Time passed since treatment started:
M
H
D
W
M
Sleepiness
Dizziness
Blurry vision
Dry mouth, nose, and throat
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The following Diphenhydramine side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Sudden eye pain or change in vision such as blurry vision, seeing halos around lights, vision loss
- Trouble passing urine
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
- Constipation
- Drowsiness
- Dry mouth
- Headache
- Upset stomach
Get your GoodRx coupon
$4.090
GoodRx discount
$4.09
Pros and cons of Diphenhydramine
Pros
- Relieves allergy and cold symptoms in about 15 to 30 minutes
- Safe for children as young as 6 years old
- Available over the counter
- Comes as pills and liquid
Cons
- Can make you feel sleepy or dizzy
- Might need to take multiple times a day for symptom relief
- Not the best choice for older adults
- Can worsen certain conditions like glaucoma and stomach ulcers
Pharmacist tips for Diphenhydramine
- Diphenhydramine can make you sleepy and dizzy. Don’t drive or do anything that needs focus until you know how it affects you.
- Avoid alcohol while taking diphenhydramine. Alcohol can make sleepiness and dizziness worse.
- Diphenhydramine can cause dry mouth. To help with dry mouth, consider chewing on sugar-free gum, sucking on ice, rinsing with cold water, or using saliva sprays or lozenges.
- Diphenhydramine might not be safe for older adults. It can raise the risk of falls because it can make you feel dizzy, tired, or cause a drop in your blood pressure. Talk to your primary care provider to be safe.
- If you're taking diphenhydramine liquid, measure doses with the device that comes with it or ask your pharmacist for one. Don't use household spoons because they can give the wrong dose.
- Don't take diphenhydramine with other antihistamines since it can raise your risk of side effects. Many cold or allergy products already contain antihistamines, so check labels carefully.
More tips if used for trouble sleeping:
- Use diphenhydramine for sleep only for short periods. If sleep problems continue, talk to your primary care provider.
- Don’t use diphenhydramine to make a child sleep. It can sometimes make children more active instead of sleepy, so talk to a pediatrician for safer options.
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Risks and warnings for Diphenhydramine
Diphenhydramine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Sleepiness
- Risk factors: Drinking alcohol while taking diphenhydramine | Taking other medications that cause sleepiness | Older adult
Diphenhydramine can make you very sleepy, which can affect your focus, thinking, and reaction time. It can also raise your risk of falls and accidents. This is more likely if you’re an older adult, drink alcohol, or take other medications that cause drowsiness (e.g., opioids, benzodiazepines, sleep medications). Don’t drive or use machinery until you know how this medication affects you.
Accidental overdose
- Risk factors: Taking other products with diphenhydramine
Many over-the-counter (OTC) products contain diphenhydramine. It's not safe to use more than one product with this medication at the same time. Taking too much can cause dry eyes or mouth, a fast heartbeat, trouble urinating, fever, or constipation. And high doses can lead to serious problems like confusion, seizures, hallucinations, low blood pressure, or heart rhythm issues.
The FDA released a warning to avoid high doses of diphenhydramine. To avoid taking too much, read labels carefully and follow the dosing instructions. If you’re not sure whether a product contains diphenhydramine, ask your pharmacist or primary care provider.
Worsening of certain health problems
- Risk factors: Glaucoma | Enlarged prostate | Breathing problems | Kidney problems
Talk to your primary care provider before taking diphenhydramine if you have glaucoma, an enlarged prostate, breathing problems (like emphysema or bronchitis), or kidney problems. This medication can make these conditions worse and might lead to serious side effects.effects.
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Diphenhydramine dosage
The average cost for 30 capsules of 25mg of Diphenhydramine is $5.05 with a free GoodRx coupon. This is 28.87% off the average retail price of $7.10.
Typical dosage for Diphenhydramine
There are different versions of diphenhydramine made by several manufacturers, and they can come in different strengths and forms. Because of this, the dose and age limits can vary by product. Always check the package label for exact directions.
Allergies and common cold symptoms:
- Adults and children 12 years and older: The typical dose is 25 mg to 50 mg by mouth every 4 to 6 hours as needed. Don't take more than 6 doses in a 24-hour period.
- Children 6 to under 12 years old: The typical dose is 12.5 mg to 25 mg by mouth every 4 to 6 hours as needed. Don't take more than 6 doses in a 24-hour period.
- Children under 6 years old: Ask your child's pediatrician.
Trouble sleeping:
- Adults and children 12 years and older: The typical dose is 50 mg by mouth at bedtime as needed. Don't take more than one dose in a 24-hour period.
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How much does Diphenhydramine cost?
To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
What are alternatives to Diphenhydramine?
There are a number of medications that your doctor can prescribe in place of Diphenhydramine. Compare a few possible alternatives below.
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Diphenhydramine images
