brompheniramine / dextromethorphan / phenylephrine
Rynex DM is a combination of three medications: brompheniramine (an antihistamine), dextromethorphan (a cough suppressant), and phenylephrine (a decongestant). Rynex DM is an over-the-counter liquid medication for adults and children with allergy and common cold symptoms, such as cough, stuffy nose, and itchy or watery eyes. It's typically taken by mouth every 4 hours as needed for symptom relief. Possible side effects include drowsiness, restlessness, dizziness, and dry mouth.
Note: This combination medication can also be found as liquids under other brand names, including Endacof DM and Children's Dimetapp Cold and Cough.
What is Rynex DM?
What is Rynex DM used for?
Short-term relief of symptoms from allergies and the common cold:
Cough from throat and lung irritation
Runny nose
Sneezing
Itchy or watery eyes
Itching of the nose or throat
Stuffy nose (nasal congestion)
How Rynex DM works
Rynex DM is a combination of three medications that work together to relieve symptoms caused by allergies and the common cold.
Brompheniramine is an antihistamine. It blocks a natural substance in your body called histamine that normally causes allergy or common cold symptoms. By blocking histamine, brompheniramine lowers inflammation (swelling) and relieves runny or itchy nose, sneezing, and watery eyes.
Dextromethorphan is a cough suppressant. It works in the brain to lower your urge to cough.
Phenylephrine is a decongestant. It works by narrowing the blood vessels in your nose and sinuses to relieve pressure.
Drug Facts
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What are the side effects of Rynex DM?
Common Side Effects
- Sleepiness
- Restlessness
- Dizziness
- Dry mouth
Other Side Effects
- Trouble sleeping
- Trouble urinating
Serious Side Effects
- Serotonin syndrome: fast heart rate, sweating, muscle stiffness or spasms, high fever, confusion
Source: DailyMed
The following 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
- Heart palpitations—rapid, pounding, or irregular heartbeat
- Increase in blood pressure
- 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):
- Anxiety, nervousness
- Confusion
- Constipation
- Dizziness
- Drowsiness
- Dry mouth
- Fatigue
Pros and cons of Rynex DM
Pros
Convenient to take three medications in one liquid product
Starts working within 30 minutes to an hour
Can treat a wide variety of allergy and common cold symptoms
Available over the counter
Cons
Might need to take every 4 hours for symptom relief
More difficult to customize the dose since it's a combination of three medications
Only available as a liquid
Not the best choice for people over 65 years old or people with glaucoma, breathing problems, stomach problems, or urinary problems
Pharmacist tips for Rynex DM
You can take Rynex DM with or without food.
Use a medication dose cup or an oral syringe to measure your dose of Rynex DM. Don't use household spoons because they might not be accurate and using them might cause you to take the wrong dose.
Rynex DM can make you feel sleepy or dizzy during the day since it contains dextromethorphan (a cough suppressant) and brompheniramine (an antihistamine). Don't drive or do anything that requires a lot of attention or focus until you know how Rynex DM affects you.
Avoid drinking alcohol while you're taking Rynex DM. Alcohol can make you feel even sleepier or dizzier.
Rynex DM can sometimes make children get overly excited or energetic. Don't give this medication to your child anymore and speak to a pediatrician if this happens to your child.
Stop taking Rynex DM and contact your healthcare team if you feel dizzy or nervous or if you have trouble sleeping. These might be side effects from the phenylephrine or other medications in Rynex DM. Your care team can give recommendations on how to lessen these side effects, such as taking the medication less often.
You should use Rynex DM to relieve cold or allergy symptoms for a short period of time only. Let a healthcare professional know if your symptoms worsen or last longer than a week. You might need other treatment to relieve your symptoms better.
Stop taking Rynex DM and tell your primary care provider if you start to have a fever, rash, or headache. These might be signs that you need more medical attention.
Don't start any new medications — especially other antihistamines, cough suppressants, or decongestants — while you're taking Rynex DM without talking to a healthcare professional first. Some medications can raise your risk for severe side effects, including extreme sleepiness, high blood pressure, fast heart rate, seizures, or hallucinations (seeing things that aren't real).
Don't use Rynex DM if you're currently taking a monoamine oxidase inhibitor (MAOI), such as selegiline or phenelzine (Nardil), or have taken one in the last 14 days. Taking this medication with an MAOI can raise your risk for severe side effects (e.g., serotonin syndrome, high blood pressure). Ask a pharmacist for other options to relieve your cough, congestion, and allergy symptoms.
Frequently asked questions about Rynex DM
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What are the risks and warnings for Rynex DM?
Rynex 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.
Serotonin syndrome
Risk factors: Taking monoamine oxidase inhibitors (MAOIs) 14 days before starting Rynex DM | Taking other medications that raise serotonin levels in your brain
The dextromethorphan in Rynex DM can raise your risk for serotonin syndrome. This is a rare, but potentially life-threatening side effect that happens when there's too much serotonin in the brain. Get medical help right away if you have any symptoms of serotonin syndrome, including fast heart rate, sweating, muscle stiffness or spasms, high fever, and confusion.
Your risk for serotonin syndrome is higher if you're also taking other medications that affect serotonin levels, such as certain antidepressants, MAOIs, and certain migraine medications. Make sure your healthcare team knows about all the medications you take or plan to take (including over-the-counter medications and supplements). They can make sure Rynex DM is safe to take with your other medications.
Accidentally taking too much medication
Rynex DM contains an antihistamine (brompheniramine), cough suppressant (dextromethorphan), and a decongestant (phenylephrine). Your risk of accidentally taking too much medication is higher if you use more than one medication with the same or similar ingredients. Antihistamines, dextromethorphan, and decongestants are in many other over-the-counter products. Tell your primary care provider or pharmacist about the medications you take or plan to take to make sure it's safe to take with Rynex DM.
Early signs that you might've accidentally taken too much medication include confusion, not being aware of your surroundings, flushed or very warm skin, and vision changes. It could also lead to anxiety or other behavior changes, high blood pressure, and trouble breathing. Get medical help right away or contact a Poison Control Center at 1-800-222-1222 if you think you or a loved one accidentally took too much medication.
To prevent accidentally taking too much medication, read the package labels of your medications, review their active ingredient list and age cut-offs, and carefully follow the directions. Don't take more than one medication with an antihistamine, dextromethorphan, or a decongestant on it. Ask a pharmacist if you're not sure whether another product has similar ingredients as Rynex DM.
Worsening of certain medical conditions
Risk factors: Cough from smoking, asthma, or emphysema | Mucus-producing cough | Breathing problems | Heart disease | High blood pressure | Thyroid problems | High blood sugar (diabetes) | Glaucoma | Urinary problems
Let your primary care provider and pharmacist know about all the medical conditions you have before you start taking Rynex DM. Ask them whether this medication is safe for you to take.
People who are 65 years of age or older might feel side effects from Rynex DM more intensely. In addition, Rynex DM might worsen certain medical conditions, such as high blood pressure and glaucoma. This medication also might not be appropriate for your condition. For example, you might need other treatment if you have a cough that's lasted for a long time; a cough that occurs with smoking, asthma, or emphysema; or a cough with a lot of mucus.
Rynex DM dosage forms
| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 2mg/10mg/5mg/10ml | 118 ml | $4.59 | $0.04 |
Typical dosing for Rynex DM
Note: There are many manufacturers that make this combination medication. They can have different amounts of medication per mL of liquid and slightly different dosages. Check the medication box for the specific instructions for your product.
Rynex DM: Each 5 mL contains 1 mg of brompheniramine, 5 mg of dextromethorphan, and 2.5 mg of phenylephrine.
Adults and children age 12 years and older: The typical dose is 20 mL (4 teaspoonfuls) by mouth every 4 hours while you're having symptoms. Don't use more than 6 doses (120 mL) in a 24-hour period.
Children age 6 years to under 12 years: The typical dose is 10 mL (2 teaspoonfuls) by mouth every 4 hours while your child is having symptoms. Don't use more than 6 doses (60 mL) in a 24-hour period.
Children under 6 years old: Ask your child's pediatrician.
How much does Rynex DM cost?
Rynex DM contraindications
Currently take or have taken a monoamine oxidase inhibitor (MAOI) in the last 2 weeks
What are alternatives to Rynex DM?
Short-term relief of symptoms from allergies and the common cold:
Cough from throat and lung irritation
Runny nose
Sneezing
Itchy or watery eyes
Itching of the nose or throat
Stuffy nose (nasal congestion)
Cough
Runny nose
Sneezing
Itchy nose or throat
Itchy or watery eyes
Stuffy nose (nasal congestion)
Sinus congestion
Cough from throat and lung irritation
Runny nose
Sneezing
Itchy or watery eyes
Itching of the nose or throat
Stuffy nose (nasal congestion)
Rynex DM images
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References
Best studies we foundBorowy, C. S., et al. (2023). Antihistamine toxicity. StatPearls.
CVS Pharmacy. (2024). Childrens Dimetapp Cold and Cough- brompheniramine maleate, dextromethorphan hbr, phenylephrine hcl liquid [package insert]. DailyMed.
Edwards Pharmaceuticals, Inc. (2023). Rynex DM- brompheniramine maleate, dextromethorphan hydrobromide, phenylephrine hydrochloride liquid [package insert]. DailyMed.
Edwards Pharmaceuticals, Inc. (2023). Rynex PE- brompheniramine maleate and phenylephrine hcl liquid [package insert]. DailyMed.
Gelotte, C. K., et al. (2015). Pharmacokinetics, safety, and cardiovascular tolerability of phenylephrine HCl 10, 20, and 30 mg after a single oral administration in healthy volunteers. Clinical Drug Investigation.
Hoeft, D., et al. (2014). An overview of clinically significant drug interactions between medications used to treat psychiatric and medical conditions. Mental Health Clinician.
Oh, S., et al. (2023). Dextromethorphan. StatPearls.
Spangler, D. C., et al. (2016). Dextromethorphan: A case study on addressing abuse of a safe and effective drug. Substance Abuse Treatment, Prevention, and Policy.
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