Diphenhydramine is a medication to relieve symptoms due to allergic reactions, allergic rhinitis, and common cold. This drug can also be used to treat motion sickness, as well as tremors and muscle stiffness in people with Parkinson's.
Diphenhydramine works by blocking the effects of histamine in the body that causes an allergic reaction. That way, allergy symptoms, such as sneezing, rash, itching of the skin, red and watery eyes, runny nose, due to allergic rhinitis or common cold, will subside.
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What is Diphenhydramine
| group | Over-the-counter and prescription drugs |
| Category | Antihistamines |
| Benefit | Relieves symptoms of allergies, allergic rhinitis, common cold, motion sickness, and symptoms of Parkinson's disease. |
| Used by | Adults and children 2 years old |
| Diphenhydramine for pregnant and lactating women | Category B: Animal studies have not shown a risk to the fetus, but there are no controlled studies in pregnant women. Diphenhydramine is absorbed into breast milk. This medicine can also reduce milk production. If you are breastfeeding, do not use diphenhydramine without consulting your doctor first. |
| Drug form | Tablets, caplets, syrups, ointments, suppositories, injections |
Warning Before Using Diphenhydramine
Diphenhydramine should not be used carelessly. Although this medicine is sometimes found in over-the-counter cold and cough medicines, there are a few things you should pay attention to before using this medicine, namely:
- Do not use diphenhydramine if you are allergic to this drug.
- Tell your doctor if you have or have had asthma, emphysema, chronic bronchitis, glaucoma, hypertension, heart disease, liver disease, seizures, hyperthyroidism, enlarged prostate, or peptic ulcers.
- Do not give diphenhydramine to children without consulting their doctor first.
- Consult a doctor first before giving diphenhydramine to the elderly. This is because the risk of side effects, such as drowsiness, dizziness, or difficulty urinating, will increase if given in this age group.
- Do not drive or do activities that require alertness, after using diphenhydramine, because this medicine may cause dizziness or drowsiness.
- Tell your doctor if you plan to have allergy testing, dental work, or surgery.
- Tell your doctor if you are taking certain medications, supplements, or herbal products.
- Tell your doctor if you are pregnant, planning a pregnancy, or are breastfeeding.
- Call your doctor right away if you have an allergic reaction, serious side effects, or overdose after using diphenhydramine.
Dosage and Instructions for Use of Diphenhydramine
The following is a diphenhydramine dosage grouped according to the form of the drug and the condition being treated:
Diphenhydramine tablets, caplets and syrup
Condition: Allergic reactions, allergic rhinitis, cold cough, and motion sickness
- Adults and children age 12 years: 25–50 mg, 3-4 times daily. To prevent motion sickness, take it 30 minutes before traveling. The maximum dose is 300 mg per day.
- Children age 6–12 years: 12.5–25 mg, every 4–6 hours. To prevent motion sickness, take it 30 minutes before traveling.
- Children age 2–5 years: 6.25 mg, every 4–6 hours. To prevent motion sickness, take it 30 minutes before traveling.
Topical or topical diphenhydramine (ointment)
Condition: Pruritus (itching, rash, minor skin irritation)
For adults and children, apply diphenhydramine 2% thinly on the problem skin, a maximum of 2 times a day. Do not use this medicine for more than 3 days.
Diphenhydramine injection
Condition: Allergic reactions or motion sickness
- Mature: 10–50 mg by injection into a vein (IV/intravenous) or muscle (IM/intramuscularly). The dose may be increased to 100 mg if needed. The maximum dose is 400 mg per day.
- Children: 5 mg/kg body weight per day divided into 4 times given by injection into a vein or muscle. The maximum dose is 300 mg per day.
Condition: Symptoms of Parkinson's disease
- Mature: 10–50 mg by injection into a vein or muscle. The dose may be increased to 100 mg if needed. The maximum dose is 400 mg per day.
In addition, diphenhydramine can also be found in the form of suppositories to treat anal itching. For this purpose usually diphenhydramine will be combined with other drugs and ingredients. The general dose for this dosage form is 1 suppository inserted into the rectum, use 3 times a day in the morning, afternoon, and evening.
How to Use Diphenhydramine Correctly
Follow the doctor's advice and read the information listed on the packaging label before using diphenhydramine. Use diphenhydramine according to the prescribed dose. Injectable diphenhydramine should only be given by medical personnel under the supervision of a doctor.
Take diphenhydramine tablets whole with a glass of water. Do not split, crush, or chew the medicine as this may increase the side effects.
For diphenhydramine syrup, take it using a measuring spoon that is usually provided in the package. Do not use a regular tablespoon because dosage sizes may vary.
For diphenhydramine suppositories, wash your hands before and after using this medication. Remove the package and wet the medicine with cold water. Position yourself on your side, then insert the suppository into your rectum with your finger. If the suppository is too soft to insert, refrigerate it for 30 minutes before using it.
Try to always take diphenhydramine at the same time every day to get optimal treatment results.
Make sure that there is sufficient time between one dose and the next. If you forget to use diphenhydramine, use it immediately if the break with the next schedule of use is not too close. If it is close, ignore it and do not double the dose.
Store diphenhydramine in a closed place in a cool temperature. Protect this medication from exposure to direct sunlight. Keep out of reach of children.
Interactions of Diphenhydramine with Other Drugs
The use of diphenhydramine together with other drugs can cause the following drug interactions:
- Increases drowsiness and side effects that can be fatal when used with sedatives, antidepressants, or other antihistamines, such as hydroxyzine
- Enhances the effect of anticholinergic drugs, such as atropine
- Reduces the effectiveness of betahistine
Diphenhydramine Side Effects and Dangers
Some of the side effects that may appear after using diphenhydramine are:
- Dry mouth, nose or throat
- Drowsiness
- Dizzy
- Nausea or vomiting
- Constipation
- Headache
- Restless or nervous
- Euphoria especially in children
- Chest feels tight or pressured
- Loss of appetite
- Rash, redness, itching, burning, or mild irritation on the skin when diphenhydramine is applied
Check with your doctor if the side effects above don't go away or get worse. See your doctor immediately if you have an allergic reaction to the drug or a more serious side effect, such as:
- Heart beat
- Visual disturbance
- Pain or difficulty urinating
- Tongue moves uncontrollably
- Erectile dysfunction
- Confusion
- Feel like fainting