Alahist DM
Alahist DM is a combination medication containing three active ingredients: dextromethorphan (a cough suppressant), pheniramine (an antihistamine), and phenylephrine (a decongestant). It's used in adults and children to treat symptoms caused by allergies and the common cold, such as cough, runny nose, and congestion. Alahist DM is taken by mouth, typically every 4 to 6 hours. Possible side effects of this medication include sleepiness and dizziness. It's available over the counter as a sugar-free, alcohol-free, dye-free flavored liquid.
What is Alahist DM?
What is Alahist DM used for?
Short-term relief of symptoms from allergies and the common cold:
Runny nose
Sneezing
Itchy or watery eyes
Itching of the nose or throat
Cough from throat and lung irritation
Stuffy nose (nasal congestion)
How Alahist DM works
Alahist 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 works in the brain to lower your urge to cough.
Pheniramine is an antihistamine. It blocks a natural substance in your body called histamine. In doing so, it lowers inflammation (swelling) and relieves runny nose, itchy nose, and sneezing.
Phenylephrine is a decongestant. It's thought to work by narrowing the blood vessels in the nose to relieve sinus pressure.
Drug Facts
Get your GoodRx coupon
What are the side effects of Alahist DM?
Common Side Effects
- Sleepiness
- Restlessness
- Dizziness
- Nausea
- Stomach discomfort
Other Side Effects
- Trouble sleeping
- Trouble urinating
- Headache
Serious Side Effects
- Serotonin syndrome: fast heart rate, sweating, muscle stiffness or spasms, high fever, confusion
Source:Â 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 Alahist DM
Pros
Starts working within 30 minutes to an hour
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
Cons
Might need to take multiple times a day
More difficult to customize the dose since Alahist DM is a fixed combination of three medications
Older adults are at higher risk for sleepiness
Pharmacist tips for Alahist DM
You can take Alahist DM with or without food. If it upsets your stomach, try taking the medication with food.
Use a medication dose cup or an oral syringe to measure out your dose of Alahist 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.
The pheniramine (antihistamine) and dextromethorphan (a cough suppressant) in Alahist 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 Alahist DM affects you.
Avoid drinking alcohol while you're taking Alahist DM because doing so can make sleepiness worse.
Although pheniramine (antihistamine) and dextromethorphan (a cough suppressant) usually make adults sleepy, they can cause children to become overly excited or energetic. Stop Alahist DM and speak to a pediatrician if this happens to your child.
If your symptoms worsen or last longer than a week even after starting Alahist DM, or you start to have a fever or rash, contact your primary care provider. These might be signs of a more serious condition.
Read the ingredients label on all the medications you're taking. Many over-the-counter cold and flu medications contain the same ingredients as those in Alahist DM. Taking more than one cough suppressant, antihistamine, or decongestant at the same time can raise the risk of overdose and severe side effects, such as agitation and trouble breathing.
Don't take Alahist DM if you're currently taking or have taken a monoamine oxidase inhibitor (MAOI) in the last 2 weeks. This combination can raise your risk for severe side effects such as serotonin syndrome and dangerously high blood pressure. Ask your pharmacist or primary care provider for other options to relieve your cough, congestion, and allergy symptoms.
Frequently asked questions about Alahist DM
How to save using GoodRx
What are the risks and warnings for Alahist DM?
Alahist 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 (MAOI) 14 days before starting Alahist DM | Taking other medications that raise serotonin levels in your brain
The dextromethorphan in Alahist DM can raise your risk for serotonin syndrome, a rare, but potentially life-threatening side effect. Your risk 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 (including over-the-counter medications and supplements) before starting Alahist DM so they can make sure this medication is safe for you to take. Don't start any new medications while taking Alahist DM without letting your pharmacist or prescriber know. Symptoms of serotonin syndrome include fast heart rate, sweating, muscle stiffness or spasms, high fever, and confusion. Get medical help right away if you have any of these symptoms.
Accidental overdose
Alahist DM contains a cough suppressant (dextromethorphan), an antihistamine (pheniramine), and a decongestant (phenylephrine). Taking more than one medication containing an antihistamine, cough suppressant, or a decongestant can lead to an accidental overdose, which can be life-threatening.
To prevent an accidental overdose, read the medication box and package labels carefully so you're aware of the ingredients, age-cut offs, and maximum dosing of your particular product. 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 Alahist DM.
Some signs of taking too much medication can include anxiety or other behavior changes, high blood pressure, and trouble breathing. If you or your loved one experiences an accidental overdose, get medical help as soon as possible.
Worsening of certain medical conditions
Risk factors: Breathing problems | Glaucoma | Urinary problems | Cough from smoking, asthma, or emphysema | Mucus-producing cough | Heart disease or high blood pressure | Thyroid problems | High blood sugar (diabetes)
Make sure your primary care provider and pharmacist know about all your medical conditions before you take Alahist DM. Ask them whether this medication is safe and appropriate for you.
People who are 65 years of age or older are at higher risk of more severe side effects from Alahist DM. In addition, Alahist DM might worsen the symptoms of 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.
Alahist DM dosage forms
| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 473ml of 10mg/12.5mg/5mg/5ml | 1 bottle | $33.74 | $33.74 |
Typical dosing for Alahist DM
Each 5 mL of Alahist DM contains 10 mg of dextromethorphan, 12.5 mg of pheniramine, and 5 mg of phenylephrine.
People ages 12 years or older: The typical dose is 10 mL by mouth every 4 to 6 hours. Don't take more than 60 mL in a 24-hour period.
Children ages 6 years to under 12 years old: The typical dose is 5 mL by mouth every 4 to 6 hours. Don't take more than 30 mL in a 24-hour period.
Children under 6 years old: Ask your child's pediatrician.
How much does Alahist DM cost?
Alahist DM contraindications
Currently take or have taken a monoamine oxidase inhibitor (MAOI) in the last 2 weeks
What are alternatives to Alahist DM?
Short-term relief of symptoms from allergies and the common cold:
Runny nose
Sneezing
Itchy or watery eyes
Itching of the nose or throat
Cough from throat and lung irritation
Stuffy nose (nasal congestion)
Runny nose
Sneezing
Itchy nose or throat
Itchy, watery eyes
Cough
Stuffy nose (nasal congestion)
Cough from scratchy throat
Runny nose
Sneezing
Itchy or watery eyes
Stuffy nose
Itchy nose or throat
Get savings updates for Alahist DM
Receive price alerts, news, and other messages from GoodRx about Alahist DM and other healthcare topics and relevant savings offers.By providing your email, you consent to receive marketing communications from GoodRx, which may include content and/or data related to men’s health, women's health, reproductive care, or sexual health. You agree to the GoodRx Terms of Use and acknowledge the Privacy Policy. You can unsubscribe at any time.
References
Best studies we foundBorowy, C. D., et al. (2023). Antihistamine toxicity. StatPearls.
Department of Justice/Drug Enforcement Administration. (2020). Narcotics.
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. (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.
Poly Pharmaceuticals, Inc. (2024). Alahist DM- dextromethorphan hbr, pheniramine maleate, phenylephrine hcl liquid [package insert]. DailyMed.
Browse medications
View AllResearch prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.