What is diphenhydramine?

Diphenhydramine is an antihistamine that is effective in treating the symptoms of allergies, colds, and hay fever. These symptoms include rash and hives, itching, runny nose, tears, itchy eyes, itchy nose and throat, cough and sneezing. Diphenhydramine syrup is also used for the symptomatic treatment of Parkinson’s and extrapyramidal reactions.

Diphenhydramine is used to prevent and treat nausea, vomiting and dizziness caused by travel or movement (such as car sickness). In addition, diphenhydramine can be effective in increasing relaxation and treating insomnia.

Diphenhydramine compound is a combination of two drugs, diphenhydramine and ammonium chloride. Each 5 ml of diphenhydramine compound syrup contains 12.5 mg of diphenhydramine hydrochloride and 125 mg of ammonium chloride. Diphenhydramine compound is also used with antihistamine properties to reduce cold symptoms. In addition, diphenhydramine compound is used to relieve dry and noisy coughs or phlegm coughs.

How to use diphenhydramine

Use diphenhydramine exactly as directed on the label, or as directed by your doctor. Do not use it in larger or smaller amounts or more than the recommended amount.

Cold or allergy medicine is usually only used for a short time until your symptoms clear up. Do not give this medicine to a child younger than 2 years old.

Always ask your doctor for advice before giving your child cough medicine or cold medicine. Death due to abuse of cough medicine and cold medicine is common in young children. You should not use diphenhydramine to make the child sleep.

Pharmaceutical forms

Diphenhydramine drug has different forms that we have mentioned below.

Diphenhydramine syrup and other forms
This medicine is available in pharmacies in the form of syrup.

Diphenhydramine is available in the form of soft gel, tablets and ampoules. But the most common form of this drug is diphenhydramine syrup.

Note: The article you are reading is only for raising awareness and does not replace the doctor’s advice in any way. It is necessary to consult a specialist doctor for taking medicine, knowing about side effects, drug interaction and other related matters.


We know that diphenhydramine is used for allergy symptoms and fever and cold. This antihistamine drug is one of the most widely used and suitable drugs. This medicine relieves the symptoms of runny nose, fever, congestion and other symptoms related to allergies and sensitivities. These effects are due to blocking histamine.

What is the difference between diphenhydramine compound and simple syrup?

Compound diphenhydramine syrup contains ammonium chloride, while simple diphenhydramine does not. For this reason, diphenhydramine compound is very effective for eliminating cough with sputum.

Another difference between diphenhydramine compound and simple diphenhydramine is when used by children. It is not recommended to use diphenhydramine compound in children, but simple diphenhydramine is not prohibited in children older than two years with a doctor’s prescription.

Diphenhydramine to treat covid-19?

Diphenhydramine is one of the common drugs in the prescription of corona patients. Corona causes many symptoms by involving the upper respiratory system. Cough is one of the early symptoms of Corona. Compound and plain diphenhydramine are both effective in relieving dry coughs of Corona.

A runny nose is one of the symptoms of Corona Amicron. It seems that this drug is also useful for relieving a runny nose.

But it is highly recommended that if you experience the symptoms of corona and your corona test is positive, do not take any medicine without consulting an infectious disease doctor.

Diphenhydramine syrup for sore throat
Diphenhydramine syrup is also used for cough and sore throat. This drug is the most common drug for treating colds and improving symptoms of corona. Because of its antihistamine effects, it also affects sore throat and cough. If sore throat and cough are due to allergies and sensitivity, it will definitely improve with diphenhydramine.


The reported dosage for adults using diphenhydramine is 100 mg as a single dose and 300 mg every 24 hours. But the amount of the dose depends entirely on the condition in which you are going to take this medicine. Also, the type of diphenhydramine syrup used is also effective in determining the dosage.

One of the most widely used drugs of this era is diphenhydramine, which usually accounts for 3.2% of overdose deaths related to this drug. Therefore, it is important and effective to comply with the permitted and maximum dose of this drug. Note that you should consult your doctor about this issue.

The most frequent overdose happens to children under 6 years old who use diphenhydramine syrup. But adults are not safe from this incident either.

How to use and dosage

In order to use Diphenhydramine correctly, it is necessary to follow the information on the cover of the medicine carefully. If the doctor prescribes diphenhydramine syrup, follow the doctor’s instructions.

Take diphenhydramine tablets, capsules or syrup with or without food.
If you are using diphenhydramine syrup, use a special measure.
The dosage of diphenhydramine depends on your age, the condition of the disease, and the response of your body to the treatment.
There are also different brands and forms of diphenhydramine available in the market. For this reason, it is necessary to carefully read the instructions for using diphenhydramine because its amount is different in different products.
Pay attention not to arbitrarily increase the dose of the drug to more than the prescribed amount.
This drug is available over the counter and with a prescription.
The maximum effect of diphenhydramine syrup is 2 hours after consumption and its effect decreases after 7 hours.
It is forbidden to use diphenhydramine compound more than 6 times a day.
To prevent movement disorders, take the medicine 30 minutes before performing activities such as traveling.
If you use it to treat movement disorders or insomnia, take it 30 minutes before moving or bedtime.
If you still have trouble sleeping after 2 weeks of taking diphenhydramine, contact your internal medicine doctor, general practitioner, or ear, nose and throat specialist.

Correct dosage

Allergic rhinitis, hives and colds

25 to 50 mg every 4 to 6 hours as needed
Maximum dose: 300 mg per day
Car sickness (motion sickness)

25 to 50 mg three to four times a day
First dose 30 minutes before departure

50 mg a day before going to bed
Extrapyramidal complications

25 to 50 mg three to four times a day
If you miss a dose of diphenhydramine
It often happens that people cannot take their medicines regularly, accurately and on time. Sometimes it happens that they forget their medicine. Therefore, we should know when it is appropriate to take medicines and follow it, and be familiar with the tips of forgetting the dose of medicine.

But what if we forget to take diphenhydramine?

If you miss a dose for a few hours, it’s okay, just take the missed dose as soon as you remember. But if you remember the missed dose close to taking the next dose, do not take it and do not double the dose the next day or the next hour.

side effects

If the doctor has prescribed diphenhydramine for you, be sure that its benefits are more than its harms. It is also important to know that most people who have taken diphenhydramine have not experienced any serious side effects.

Taking diphenhydramine and diphenhydramine compound may lead to side effects such as unconsciousness, confusion, constipation, digestive discomfort, blurred vision, dry mouth and nose, eyes and throat.

The most common side effect of diphenhydramine syrup is drowsiness. Another common side effect of diphenhydramine is dry mouth. You can use gum (without sugar), suck candy (without sugar) or an ice cube, drink water to fix it.

If you experience side effects such as mood changes (restlessness, confusion), rapid or irregular heartbeat, or urinary disorders, inform your doctor immediately.

It is important to know that a serious allergic reaction to diphenhydramine is rare. However, if you experience a serious allergic reaction such as skin symptoms, itching, swelling (especially of the face, tongue, and throat), severe confusion, and difficulty breathing, seek emergency medical help immediately.

Considering that the list of complications is not complete, you may encounter a complication that is not mentioned. In these cases, consult a doctor or pharmacist.

Dangerous side effects

If you have any of the following symptoms, you should immediately call the emergency room;

  1. If you experience palpitations or an increased heart rate, see your doctor immediately.
  2. Call 911 if you feel tingling or numbness.
  3. If you feel confused or tired.

Precautions for use

Before use, if you are allergic to diphenhydramine, discuss this issue with your doctor or pharmacist. Diphenhydramine may contain inactive ingredients that may cause allergies or other problems.

medical record

If you have a history of the following diseases, be sure to tell your doctor;

  • Respiratory problems (asthma, emphysema)
  • high eye pressure (glaucoma)
  • heart problems
  • high blood pressure
  • Liver problems
  • convulsions
  • Digestive problems
  • hyperthyroidism
  • Urinary problems (such as prostate enlargement)

Diphenhydramine syrup for favism children

Favism patients, especially for children, have a list of drugs that should not be taken. Some of these drugs have a very high risk and others have a relative risk. Diphenhydramine is one of the drugs best avoided by those with favism because it carries little risk.

Can children take diphenhydramine syrup?

Children may be more sensitive to the side effects of diphenhydramine syrup. Diphenhydramine may also cause excitement in teenagers instead of unconsciousness. So, if you want to use it for children under 12 years old, be sure to consult a pediatrician or pharmaceutical consultant.

Can the elderly take diphenhydramine syrup?

Like children, the elderly are more sensitive to complications such as unconsciousness, confusion, imbalance (which can increase the risk of falling), constipation or urinary problems.

Can pregnant and lactating women take diphenhydramine syrup?

Consult your doctor for the use of diphenhydramine and diphenhydramine compound during breastfeeding. If you are pregnant, use diphenhydramine only if necessary and ask your doctor about its benefits and harms.

Medicinal ingredients

Nergic anti-coli; like morphine
Radioactive iodine
Potassium oral capsules
Oral potassium tablets

Symptoms of overdose

Taking an overdose of diphenhydramine may cause symptoms such as severe drowsiness, convulsions, and dilated pupils. Also, in children, mood changes (restlessness, sensitivity, delirium) can occur before sleepiness. If you experience serious side effects such as breathing problems by taking diphenhydramine medicine; Call emergency services


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