Dextromethorphan – Dosage, Benefits & How to Use?

What Is Dextromethorphan?

Dextromethorphan is a drug that you can use to temporarily relieve coughs caused by the flu.

This medicine can relieve coughs that can be a symptom of a disease but cannot treat the cause of the cough itself.

Dextromethorphan belongs to a class of drugs called antitussives. Antitussives work by affecting signals in the brain that trigger the cough reflex.

This medication is sold over the counter and also comes in many combination and prescription medications. Dextromethorphan is available as a syrup, capsule, chewable tablet, and lozenge.

Benefits of Dextromethorphan

The benefit of this medicine is to relieve short-term coughs caused by mild irritation of the throat or lungs. For example, flu or colds.

You should not use dextromethorphan to treat chronic coughs that occur due to smoking, asthma or emphysema, or when there is a large amount of mucus or phlegm (phlegm) with the cough.

Research on the Drug Dextromethorphan

One of the unique properties of dextromethorphan is the variety of properties it has to affect the body in different ways. This is explained in a study from StatPearls titled Dextromethorphan (2023).

This drug is lipophilic, meaning it is easily soluble in fat and has parts that can interact with other parts of the body. Dextromethorphan is thought to work in the part of the brain that controls the cough reflex.

This medication works in a complex way and interacts with different parts of the body to suppress coughing. The effects of dextromethorphan can vary from person to person, depending on how their body processes the medication.

Dextromethorphan Trademark

There are several brands of dextromethorphan that you can use, for example:

• Actifed Plus Cough Suppressant Syrup 60 ml (Red). It is a dry cough and cold medicine containing dextromethorphan HBr, pseudoephedrine HCl, and triplodine HCl.
• Anadex 10 Caplets. With the active ingredient dextromethorphan HBr, this medicine is used to treat flu symptoms such as fever, headache, sneezing, and nasal congestion accompanied by coughing.
• Vicks Formula 44 Syrup 54 ml. With a combination of dextromethorphan HBr and doxylamine succinate formulas, this medicine can relieve coughs that are not accompanied by phlegm.
• Grantusif 10 Caplets . This caplet medicine contains a combination of dextromethorphan HBr and other ingredients that are useful for treating coughs accompanied by allergies.
• OB Combi Cough and Cold 60 ml. Is a medicine that can also be used by children to relieve coughs and colds.

Dosage Dextromethorphan

The dosage of this medicine can be different for each patient. So, always follow the doctor’s advice or the instructions for use on the label on the packaging.

Avoid giving this medication to children under 4 years of age. Here are the general doses of dextromethorphan:

1. Form of lozenges

• Adults and children 12 years and older: 5 to 15 milligrams (mg) every 2-4 hours, as needed.
• Children 6-12 years: 5-15 mg every two to six hours, as needed.
• Children 4–6 years: 5 mg every four hours, as needed.

2. Syrup form

• Adults and children 12 years and older: 30 mg every 6-8 hours, as needed.
• Children 6 to 12 years of age: 7 mg every four hours or 15 mg every 6-8 hours, as needed.
• Children 4-6 years: 3.5 mg every four hours or 7.5 mg every 6-8 hours, as needed.

3. Strip shape

• Age 6-12 years: 15 mg every 6-8 hours, not to exceed 60 mg per day.
• Age > 12 years: 30 mg every 6-8 hours, not exceeding 120 mg per day.

Facts About Dextromethorphan

1. High doses of this drug can cause hallucinations.
2. The metabolism of this drug varies from person to person.
3. Because of its hallucinogenic effects, this drug is often abused, especially among teenagers.

How to Use Dextromethorphan

Use dextromethorphan exactly as directed on the label or as your doctor has prescribed.

Do not use the medication in larger amounts or use it for longer than recommended.

You usually only need to take this cough medicine for a short time until the symptoms disappear.

Here’s how to use it:

• For the syrup form, use the measuring spoon or cup provided to get the right dose. Do not use a tablespoon to measure the dose of medicine.
• For chewable tablets, let the tablet melt in your mouth before swallowing. Tablets can also be taken by chewing and swallowing.
• You can also consume dextromethorphan in the form of a strip that dissolves in the mouth by placing it on your tongue and letting it melt in your mouth, then swallowing it.
• You can consume dextromethorphan in the form of candy (lozenges) by sucking it in your mouth until it melts.

Drink plenty of fluids to help loosen congestion and lubricate your throat while you are taking this medication.

Talk to your doctor if your symptoms do not improve after seven days of treatment or if you develop a fever along with a headache, cough, or skin rash.

Cautions for Using Dextromethorphan

There are several things you need to understand about using this drug, including:

• Avoid using dextromethorphan if you are allergic to it, other drugs, or any ingredients in the product you are taking. Check the label for ingredients.
• Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take.
• Do not use dextromethorphan if you have used an MAO inhibitor such as isocarboxazid, phenelzine, rasagiline, selegiline, tranylcypromine, or methylene blue injection in the past 14 days.
• Ask your doctor or pharmacist about using dextromethorphan if you have emphysema or chronic bronchitis.
• Tell your doctor if you are pregnant or plan to become pregnant during treatment. Dextromethorphan passes into breast milk. So, do not use this medication without telling your doctor if you are breast-feeding.
• It’s important to tell your doctor if you have phenylketonuria (PKU, an inherited condition in which you can’t break down the amino acid phenylalanine), because the artificially sweetened liquid form of this cough medicine may contain phenylalanine.

Dextromethorphan Side Effects

Dextromethorphan side effects can cause allergic reactions.

Seek emergency medical help immediately if you experience signs of an allergic reaction, such as hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Stop using this medication immediately and call your doctor if you experience any of the following serious side effects:

• Severe dizziness, anxiety, feeling restless, or nervous.
• Seizures.
• confusion, hallucinations, or
• Slow and shallow breathing.

However, dextromethorphan usually causes less serious side effects, such as:

• Stomach ache.
• Feeling sleepy.
• Nauseous.
• Headache.
• Fatigue.

Dextromethorphan Interactions

Dextromethorphan may interact with certain medications or supplements.

Here is a list of medications that doctors do not recommend you take with this cough medicine:

• Clorgyline.
• Iproniazid.
• Isocarboxazid.
• Moclobemide.
• Nialamide.
• Pargyline.
• Phenelzine.
• procarbazine.
• Rasagilin.
• Safinamid.
• Selegiline.
• Toloxaton.

Dextromethorphan Contraindications

Doctors do not recommend dextromethorphan for those who have hypersensitivity (an excessive immune system reaction that can cause adverse effects) to this cough medicine.

Updated on January 04, 2025. 

Reference:

GoodRx. Retrieved 2025. Dextromethorphan (Delsym).

Drugs. Retrieved 2025. Dextromethorphan.

Medline Plus. Retrieved 2025. Dextromethorphan.

StatPearls. Retrieved 2025. Dextromethorphan. 

Frequently Asked Questions

1. What is Dextromethorphan HBR? 

Dextromethorphan HBr is a drug used to relieve dry cough or cough without phlegm. Dextromethorphan works by suppressing the cough reflex in the brain, thereby reducing the urge to cough.

2. Which drugs contain dextromethorphan?

There are various medicines that contain dextromethorphan, for example:

• Actifed Plus Cough Supressant Sirup 60 ml (Merah).
• Anadex 10 Caplets .
• Vicks Formula 44 Syrup 54 ml .
• Grantusif 10 Caplets .
• OB Combi Cough and Cold 60 ml .