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Histex-Dm

dextromethorphan / phenylephrine / triprolidine
Used for Nasal Congestion, Allergic Rhinitis, Cold Symptoms, Cough
Used for Nasal Congestion, Allergic Rhinitis, Cold Symptoms, Cough

Histex-DM is a combination of three medications: dextromethorphan (a cough suppressant), phenylephrine (a decongestant), and triprolidine (an antihistamine). It's used for relieving symptoms caused by allergies and the common cold, such as cough; runny, stuffy, and itchy nose; and itchy eyes. Histex-DM is available over the counter and comes as a syrup that's taken by mouth every 4 hours when you have symptoms. Possible side effects include making you sleepy or dizzy. For some people, it might also keep them awake.

Reviewed by:
reviewer
Robert Chad Hakim, PharmD, BCCCP
reviewer
Kristianne Hannemann, PharmD
Last reviewed on April 7, 2024
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageCostContraindicationsAlternativesReferencesPricesMedicare
basics-icon

What is Histex-DM?

What is Histex-DM used for?

Short-term relief of symptoms from allergies and the common cold:

  • Cough

  • Runny nose

  • Sneezing

  • Itchy nose or throat

  • Itchy or watery eyes

  • Stuffy nose (nasal congestion)

  • Sinus congestion

How Histex-DM works

Histex-DM is a combination of three medications that work together to relieve symptoms caused by allergies and the common cold.

  • Dextromethorphan is a cough suppressant. It's thought to work in the brain to lower your urge to cough.

  • Phenylephrine is a decongestant. It works by making the blood vessels around your nose and sinuses narrower. This helps relieve congestion and pressure.

  • Triprolidine is an antihistamine. It blocks a natural substance in your body called histamine that normally causes allergy symptoms. By blocking histamine, triprolidine lessens inflammation (swelling) and relieves runny or itchy nose, sneezing, and watery eyes.

Are you looking for information on triprolidine (Histex PD) or Capmist DM (dextromethorphan / guaifenesin / pseudoephedrine) instead?

Drug Facts

Common BrandsHistex-DM
Drug ClassCough suppressant / Decongestant / Antihistamine
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityOver-the-counter
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What are the side effects of Histex-DM?

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

Other Side Effects

  • Feeling nervous
  • Headache
  • Trouble sleeping

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Excessive sleepiness or dizziness
  • Serotonin syndrome: fast heart rate, sweating, muscle stiffness or spasms, high fever, confusion
  • Signs of accidentally taking too much medication: seizures, heart rhythm problems, hallucinations, confusion, flushed skin, skin that's warm to the touch, vision changes

Source: DailyMed

pros-and-cons

Pros and cons of Histex-DM

thumbs-up

Pros

Can treat a wide variety of allergy and common cold symptoms

Starts working within 15 to 30 minutes

Available over the counter as a sugar-free, alcohol-free, dye-free flavored liquid

More convenient to take a product that's a combination of three medications

thumbs-down

Cons

More difficult to customize the dose since Histex-DM is a combination of three medications

Only available as a liquid

Only available as a brand-name medication

pharmacist-tips

Pharmacist tips for Histex-DM

pharmacist

  • Use a medication dose cup or an oral syringe to measure out your dose of Histex-DM. Don't use household kitchen spoons because they might not be accurate and using them might cause you to take the wrong dose. Ask your pharmacist for a measuring device for your doses if the medication doesn't come with one.

    • You can take Histex-DM as needed for cold and allergies. But when you're having symptoms, it's recommended that you take the medication every 4 hours (or as instructed by a healthcare professional) to get the most relief until your symptoms aren't as bothersome anymore.

      • Histex-DM can make some people sleepy or dizzy during the day. This might affect how well you can focus, think, and react. Don't drive until you know how Histex-DM affects you. Also avoid alcohol while you're taking this medication because it can make sleepiness worse.

        • Although Histex-DM usually makes adults sleepy, it's possible for children who take this medication to become overly excited or energetic. Speak to a pediatrician if this happens to your child.

          • Stop using Histex-DM and contact your primary care provider (PCP) if your cough or nasal congestion lasts longer than 1 week or keeps coming back. Also talk to your PCP if you get nervous; feel dizzy; can't sleep; or have a new fever, rash, headache, or any other new symptoms while you're taking this medication. Your PCP can examine you to see whether you need other treatment.

            • Don't start any new medications while you're taking Histex-DM — particularly other medications with cough suppressants, a decongestant (phenylephrine or pseudoephedrine), or other antihistamines — without talking to your PCP or pharmacist first. Taking certain medications with Histex-DM can raise your risk for serious side effects, like daytime sleepiness and high blood pressure.

              faqs

              Frequently asked questions about Histex-DM

              How often can you take Histex-DM?
              Adults and children ages 6 years and older can take Histex-DM as often as every 4 hours. But be sure to take only up to 4 doses of the medication within a 24-hour period. Follow the instructions written on the manufacturer's box. And follow the healthcare professional's (HCP's) directions if they gave you specific instructions on how to take Histex-DM (these instructions might be different than what's written on the packaging). Ask your HCP or pharmacist if you're not sure how much Histex-DM you can take and how often you should take the medication.
              Does Histex-DM make you sleepy?
              Yes, it's possible to feel sleepy after you take Histex-DM because it contains triprolidine and dextromethorphan. Both of these ingredients can cause sleepiness. But Histex-DM also contains phenylephrine, which can have the opposite effect and keep you awake. Pay attention to how Histex-DM affects your sleep. Contact your primary care provider to discuss better options for you if the medication is making you too sleepy or interrupting your sleep and it's affecting your daily activities.
              Can you take Zyrtec and Histex-DM together?
              No, don't take cetirizine (Zyrtec) or any other antihistamine with Histex-DM. Histex-DM already has an antihistamine called triprolidine in it. Taking cetirizine (Zyrtec) with Histex-DM will only raise your risk for side effects such as sleepiness, dry mouth, and dizziness. Ask your primary care provider or pharmacist for guidance if your cold or allergy symptoms aren't getting better with Histex-DM alone. There might be other options, like a steroid nasal spray, that you can try in addition to Histex-DM.
              Is Histex-DM a narcotic?
              No. Histex-DM isn't considered a narcotic because it doesn't have an opioid pain medication in it.
              Does Histex-DM have codeine in it?
              No, Histex-DM doesn't have codeine in it. But Histex-DM does contain dextromethorphan, which is a medication that lowers the urge to cough like codeine does. Histex-DM also contains other ingredients called phenylephrine, a decongestant that relieves sinus and nasal congestion, and triprolidine, an antihistamine that relieves certain allergy symptoms like runny nose, sneezing, itchy nose and throat, and watery eyes.
              Can I give Histex-DM to children?
              You can give Histex-DM to children who are 6 years of age and older. Carefully read the directions on the packaging; how much Histex-DM to give to children older than 12 years old is different than how much medication to give to children between 6 and 12 years old. Don't give Histex-DM to children younger than 6 years old unless their pediatrician specifically said it's safe for them to take the medication. This is because the dosage might be too high for them. And having too much medication in the body raises the risk for serious side effects. Ask your child's pediatrician or a pharmacist for treatment options for your child's allergy or common cold symptoms.
              Can I take Histex-DM if I'm pregnant or breastfeeding?
              Histex-DM isn't recommended while pregnant or breastfeeding. This medication contains phenylephrine, and it's not completely clear how safe phenylephrine is during pregnancy. Phenylephrine can also dry up your breast milk supply. If you're pregnant or nursing, don't take Histex-DM until you've talked to a healthcare professional first about the risks and benefits of the medication.
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              What are the risks and warnings for Histex-DM?

              Histex-DM 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.

              risk-warning

              Sleepiness

              • Risk factors: Drinking alcohol | Taking other medications that cause sleepiness | Age 65 and older

                Histex-DM can make you very sleepy, which can affect your ability to focus, think, or react. This side effect is more likely to happen or be more intense if you are over 65 years old, drink alcohol while you're taking this medication, or take other medications that cause sleepiness (e.g., opioids, benzodiazepines, sleep medications). Don't drive or operate machinery until you know how Histex-DM affects you.

                risk-warning

                Serotonin syndrome

                • Risk factors: Taking monoamine oxidase inhibitors (MAOIs) 14 days before starting Histex-DM | Taking other medications that raise serotonin levels in your brain

                  Serotonin syndrome is a rare, but potentially life-threatening condition that happens when there's too much serotonin in the brain. Serotonin is one of the chemicals in your brain responsible for your mood.

                  Your risk for developing serotonin syndrome goes up if you use more than one medication that affects serotonin levels. These medications can include Histex-DM (since it contains dextromethorphan), certain antidepressants, MAOIs, and triptans. Make sure your primary care provider (PCP) and pharmacist know about all the medications you take and plan to take (including over-the-counter medications and supplements). They can make sure Histex-DM is safe for you to take.

                  Seek medical help right away if you have symptoms of serotonin syndrome, like fast heart rate, sweating, muscle stiffness or spasms, high fever, and confusion.

                  risk-warning

                  Worsening of certain medical conditions

                  • Risk factors: Heart disease or high blood pressure | Breathing problems (e.g., emphysema, long-term bronchitis) | Cough with a lot of mucus | Thyroid disease | High blood sugar (diabetes) | Glaucoma | Urinary problems

                    Be sure your PCP and pharmacist know about all your medical conditions before you take Histex-DM. Ask them whether this medication is safe and appropriate for you.

                    Histex-DM might worsen certain medical conditions like heart disease, high blood pressure, and glaucoma. Histex-DM also might not be the most appropriate choice for you depending on your conditions. For example, there might be better treatment options if you have breathing problems related to asthma, bronchitis, emphysema, or smoking.

                    risk-warning

                    Accidentally taking too much medication

                    Histex-DM contains a cough suppressant (dextromethorphan), a decongestant (phenylephrine), and an antihistamine (triprolidine). These ingredients can all be found in many other over-the-counter products.

                    The risk of taking too much medication is higher if you use multiple products containing a cough suppressant, decongestant, or antihistamine. Ask your primary care provider or pharmacist if you're not sure whether you're taking a medication that has the same or similar ingredients as Histex-DM.

                    Accidentally taking too much medication can be harmful and cause side effects, such as daytime sleepiness, skin that's warm to the touch, and vision changes. Other serious signs include confusion, not being aware of your surroundings, and very high blood pressure. Get medical help right away or contact a Poison Control Center at 1-800-222-1222 if you think you or your loved one accidentally took too much medication.

                    dosage

                    Histex-DM dosage forms

                    The average cost for 120 ml of 20mg/10mg/2.5mg/5ml of Histex-DM is $11.71 with a free GoodRx coupon. This is 27.08% off the average retail price of $16.05.
                    ml of oral solution
                    Ml of oral solution
                    DosageQuantityPrice as low asPrice per unit
                    20mg/10mg/2.5mg/5ml120 ml$11.71$0.10

                    Typical dosing for Histex-DM

                    Each teaspoonful (5 mL) of Histex-DM contains 20 mg of dextromethorphan, 10 mg of phenylephrine, and 2.5 mg of triprolidine.

                    • Age 12 years and older: The typical dose is 1 teaspoonful (5 mL) by mouth every 4 hours when you're having symptoms. Don't take more than 4 teaspoonfuls (20 mL) in a 24-hour period.

                    • Age 6 years to under 12 years: The typical dose is one-half teaspoonful (2.5 mL) by mouth every 4 hours when your child is having symptoms. Don't take more than 2 teaspoonfuls (10 mL) in a 24-hour period.

                    • Age under 6 years: Ask your child's pediatrician.

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                    How much does Histex-DM cost?

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                    contraindications-icon

                    Histex-DM contraindications

                    Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Histex-DM will not be safe for you to take.
                    alternatives

                    What are alternatives to Histex-DM?

                    There are a number of medications that your doctor can prescribe in place of Histex-DM. Compare a few possible alternatives below.
                    Histex-DM
                    Used for:

                    Short-term relief of symptoms from allergies and the common cold:

                    • Cough

                    • Runny nose

                    • Sneezing

                    • Itchy nose or throat

                    • Itchy or watery eyes

                    • Stuffy nose (nasal congestion)

                    • Sinus congestion

                    $11.71 Lowest GoodRx priceView Prices
                    Rynex DM
                    Used for:

                    • Cough from throat and lung irritation

                    • Runny nose

                    • Sneezing

                    • Itchy or watery eyes

                    • Itching of the nose or throat

                    • Stuffy nose (nasal congestion)

                    $5.49 Lowest GoodRx priceView Prices
                    Alahist CF
                    Used for:

                    • Cough from throat and lung irritation

                    • Runny nose

                    • Sneezing

                    • Itchy or watery eyes

                    • Itching of the nose or throat

                    • Stuffy nose (nasal congestion)

                    $16.72 Lowest GoodRx priceView Prices

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                    References

                    Best studies we found

                    Allegis Pharmaceuticals, LLC. (2024). Histex-DM- dextromethorphan hydrobromide, phenylephrine hydrochloride, and triprolidine hydrochloride syrup [package insert]. DailyMed.

                    Department of Justice/Drug Enforcement Administration. (2020). Narcotics.

                    Hoeft, D. (2014). An overview of clinically significant drug interactions between medications used to treat psychiatric and medical conditions. Mental Health Clinician.

                    View All References (4)

                    Johnson, D. A., et al. (1993). The pharmacology of alpha-adrenergic decongestants. Pharmacotherapy.

                    Morice, A., et al. (2016). Comprehensive evidence-based review on European antitussives. British Medical Journal Open.

                    Oh, S., et al. (2023). Dextromethorphan. StatPearls.

                    Sur, D. K., et al. (2010). Treatment of allergic rhinitis. American Family Physician.

                    GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.
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