Alahist DM Liquid
It is used to treat nose stuffiness.It is used to ease allergy signs.It is used to relieve coughing.
Drug Class
Antihistamine, Antitussive, Decongestant Combination
Pharmacologic Class
First-generation H1-antagonist; NMDA receptor antagonist, Sigma-1 receptor agonist; Alpha-1 adrenergic agonist
Pregnancy Category
Category C
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Alahist DM Liquid is a medicine that helps relieve cold and allergy symptoms like sneezing, runny nose, watery eyes, cough, and nasal congestion. It contains an antihistamine (dexbrompheniramine) to reduce allergy symptoms, a cough suppressant (dextromethorphan) to calm coughs, and a decongestant (phenylephrine) to clear stuffy noses.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, it's essential to follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. When measuring liquid doses, use the measuring device that comes with the medication. If one is not provided, ask your pharmacist for a suitable device to ensure accurate measurement.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you're unsure about the best way to dispose of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
What to Do If You Miss a Dose
If you take this medication regularly, take the missed dose as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
To get the most benefit from your medication, it's essential to follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. If it causes stomach upset, taking it with food may help. When measuring liquid doses, use the measuring device that comes with the medication. If one is not provided, ask your pharmacist for a suitable device to ensure accurate measurement.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you're unsure about the best way to dispose of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
What to Do If You Miss a Dose
If you take this medication regularly, take the missed dose as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Avoid driving or operating heavy machinery until you know how this medicine affects you, as it may cause drowsiness.
- Avoid alcohol while taking this medication, as it can increase drowsiness and other side effects.
- Drink plenty of fluids to help thin mucus and soothe your throat.
- Do not exceed the recommended dose, as this can lead to serious side effects.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
10 mL every 4 hours
Condition-Specific Dosing:
maxDailyDose:
Do not exceed 6 doses in 24 hours
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established (generally not recommended under 2 years)
Child:
Children 6 to under 12 years: 5 mL every 4 hours (max 6 doses/24 hours); Children under 6 years: Consult a doctor (often not recommended)
Adolescent:
Adolescents 12 years and older: 10 mL every 4 hours (max 6 doses/24 hours)
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; consider dose reduction
Moderate:
Use with caution; consider dose reduction
Severe:
Avoid or use with extreme caution; significant dose reduction likely needed
Dialysis:
Not well studied; components are dialyzable to varying degrees. Avoid or use with extreme caution.
Hepatic Impairment:
Mild:
Use with caution; consider dose reduction
Moderate:
Use with caution; consider dose reduction
Severe:
Avoid or use with extreme caution; significant dose reduction likely needed
Confidence:
Medium
Pharmacology
Mechanism of Action
Dexbrompheniramine: Competes with histamine for H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract, thereby preventing the effects of histamine. Possesses anticholinergic and sedative properties. Dextromethorphan: Acts centrally on the cough center in the medulla to elevate the cough threshold. It is a sigma-1 receptor agonist and an NMDA receptor antagonist (at higher doses). Phenylephrine: A direct-acting sympathomimetic amine that acts predominantly on alpha-adrenergic receptors in the respiratory tract mucosa, producing vasoconstriction, which results in shrinkage of swollen mucous membranes, reduction of tissue hyperemia, edema, and nasal congestion.
Pharmacokinetics
Absorption:
Bioavailability:
Not available (for combination); Dexbrompheniramine: ~40-60%; Dextromethorphan: ~11% (due to first-pass); Phenylephrine: ~38% (oral)
Tmax:
Dexbrompheniramine: 2-5 hours; Dextromethorphan: 2-2.5 hours; Phenylephrine: 0.75-2 hours
FoodEffect:
May delay absorption but not significantly alter extent.
Distribution:
Vd:
Dexbrompheniramine: ~2.8 L/kg; Dextromethorphan: Not well established; Phenylephrine: Not well established
ProteinBinding:
Dexbrompheniramine: ~70%; Dextromethorphan: Not well established; Phenylephrine: Not well established
CnssPenetration:
Dexbrompheniramine: Yes (causes sedation); Dextromethorphan: Yes; Phenylephrine: Limited (at therapeutic doses)
Elimination:
HalfLife:
Dexbrompheniramine: 10-20 hours; Dextromethorphan: 1.4-3.9 hours (parent), 10-20 hours (dextrorphan); Phenylephrine: 2-3 hours
Clearance:
Not available
ExcretionRoute:
Renal (primarily)
Unchanged:
Dexbrompheniramine: ~34%; Dextromethorphan: <1%; Phenylephrine: ~2.6%
Pharmacodynamics
OnsetOfAction:
Dexbrompheniramine: 15-60 minutes; Dextromethorphan: 15-30 minutes; Phenylephrine: 15-30 minutes
PeakEffect:
Dexbrompheniramine: 2-6 hours; Dextromethorphan: 2-3 hours; Phenylephrine: 1-2 hours
DurationOfAction:
Dexbrompheniramine: 4-6 hours; Dextromethorphan: 5-6 hours; Phenylephrine: 4-6 hours
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Fast heartbeat
Shakiness
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Dizziness or drowsiness
Feeling nervous or excitable
Trouble sleeping
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Fast heartbeat
Shakiness
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Dizziness or drowsiness
Feeling nervous or excitable
Trouble sleeping
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or drowsiness
- Nervousness, restlessness, or tremors
- Fast or pounding heartbeat
- Difficulty urinating
- Blurred vision
- Hallucinations or confusion
- Signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
- Persistent cough or cough with excessive phlegm (mucus) that does not improve
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
If you have a cough that produces a lot of mucus, a persistent cough caused by smoking or exposure to smoke, or lung conditions like asthma or emphysema.
If you have taken certain medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as this may lead to severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications can interact with this drug.
Additionally, it is crucial to provide your doctor and pharmacist with a comprehensive list of all your medications, including:
Prescription and over-the-counter (OTC) medications
Natural products
* Vitamins
You must also inform them about any existing health problems. This information will help your doctor determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
If you have a cough that produces a lot of mucus, a persistent cough caused by smoking or exposure to smoke, or lung conditions like asthma or emphysema.
If you have taken certain medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as this may lead to severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications can interact with this drug.
Additionally, it is crucial to provide your doctor and pharmacist with a comprehensive list of all your medications, including:
Prescription and over-the-counter (OTC) medications
Natural products
* Vitamins
You must also inform them about any existing health problems. This information will help your doctor determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere strictly to the dosage instructed by your doctor, as exceeding the recommended dose may increase your risk of experiencing severe side effects. Additionally, do not take this medication for a longer duration than prescribed by your doctor.
Until you are aware of how this medication affects you, it is advisable to avoid operating a vehicle and engaging in other activities that require alertness. It is also recommended to refrain from consuming alcohol while taking this drug. Before using marijuana, other cannabis products, or any prescription or over-the-counter medications that may cause drowsiness, consult with your doctor to discuss potential interactions.
When administering this medication to a child, exercise caution, as children may have a higher risk of experiencing excitability. If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor, as it is crucial to discuss the potential benefits and risks of this medication to both you and your baby.
Until you are aware of how this medication affects you, it is advisable to avoid operating a vehicle and engaging in other activities that require alertness. It is also recommended to refrain from consuming alcohol while taking this drug. Before using marijuana, other cannabis products, or any prescription or over-the-counter medications that may cause drowsiness, consult with your doctor to discuss potential interactions.
When administering this medication to a child, exercise caution, as children may have a higher risk of experiencing excitability. If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor, as it is crucial to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Extreme drowsiness or sedation
- Dizziness, confusion, hallucinations
- Nausea, vomiting
- Rapid heart rate, palpitations, high blood pressure
- Seizures
- Difficulty breathing
- Dilated pupils
- Urinary retention
- Dry mouth, flushed skin
What to Do:
Seek immediate medical attention or call Poison Control at 1-800-222-1222. Be prepared to provide information about the amount taken and when.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) (concurrent use or within 14 days of stopping MAOIs due to risk of hypertensive crisis with phenylephrine and serotonin syndrome with dextromethorphan)
- Other sympathomimetics (e.g., other decongestants, amphetamines) (increased risk of cardiovascular effects)
- Linezolid (MAOI activity)
Major Interactions
- CNS Depressants (e.g., alcohol, sedatives, hypnotics, anxiolytics, opioids) (additive CNS depression with dexbrompheniramine)
- Serotonergic drugs (e.g., SSRIs, SNRIs, TCAs, triptans, tramadol, St. John's Wort) (increased risk of serotonin syndrome with dextromethorphan)
- Antihypertensives (e.g., beta-blockers, ACE inhibitors) (phenylephrine may reduce their effect)
- Digoxin (phenylephrine may increase risk of arrhythmias)
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine) (may increase dextromethorphan levels and risk of toxicity)
Moderate Interactions
- Anticholinergic drugs (e.g., tricyclic antidepressants, atropine, some antipsychotics) (additive anticholinergic effects with dexbrompheniramine)
- Beta-agonists (e.g., albuterol) (additive cardiovascular effects with phenylephrine)
- Diuretics (phenylephrine may reduce their effect)
Minor Interactions
- Food (may delay absorption)
Monitoring
Symptom Monitoring
- Effectiveness of symptom relief (cough, congestion, sneezing, runny nose)
- Drowsiness or sedation
- Dizziness
- Nervousness, restlessness, or insomnia
- Increased heart rate or palpitations
- Increased blood pressure
- Dry mouth, blurred vision, urinary retention (anticholinergic effects)
- Signs of serotonin syndrome (agitation, confusion, rapid heart rate, fever, sweating, muscle rigidity, tremors, twitching, nausea, vomiting, diarrhea)
Special Patient Groups
Pregnancy
Category C. Use only if the potential benefit justifies the potential risk to the fetus. Decongestants like phenylephrine are generally avoided in the first trimester due to theoretical risks of vascular disruption, and antihistamines can cause sedation. Consult a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Phenylephrine: Theoretical risk of vascular disruption; Dexbrompheniramine: Limited data, generally avoided.
Second Trimester:
Generally considered safer than first trimester, but still use with caution.
Third Trimester:
Phenylephrine: May cause uterine vasoconstriction; Dexbrompheniramine: May cause irritability or sedation in neonates if used close to delivery.
Lactation
Use with caution. Dexbrompheniramine and phenylephrine are excreted in breast milk and may cause irritability, drowsiness, or decreased milk supply (phenylephrine) in the infant. Dextromethorphan is generally considered low risk. Consult a healthcare provider.
Infant Risk:
Low to Moderate (irritability, drowsiness, potential for decreased milk supply)
Pediatric Use
Not recommended for children under 6 years of age without consulting a doctor due to potential for serious side effects and lack of proven efficacy. Dosing for children 6-12 years must be carefully followed. Overdose can be serious in children.
Geriatric Use
Use with caution. Elderly patients are more susceptible to the anticholinergic effects (e.g., dry mouth, urinary retention, confusion, constipation) of dexbrompheniramine and the cardiovascular effects (e.g., increased blood pressure, heart rate) of phenylephrine. Start with lower doses and monitor closely.
Clinical Information
Clinical Pearls
- This combination product addresses multiple cold/allergy symptoms (cough, congestion, sneezing, runny nose).
- Advise patients to avoid other products containing antihistamines, decongestants, or cough suppressants to prevent accidental overdose.
- Warn patients about potential drowsiness and to avoid activities requiring mental alertness.
- Counsel patients on the importance of not exceeding the recommended dose, especially in children, due to the risk of serious side effects from phenylephrine and dextromethorphan.
- Monitor for signs of CNS stimulation (nervousness, insomnia) or depression (drowsiness) and adjust use accordingly.
- Patients with underlying conditions like high blood pressure, heart disease, thyroid disease, diabetes, or glaucoma should consult a doctor before use due to phenylephrine content.
Alternative Therapies
- Single-ingredient antihistamines (e.g., loratadine, cetirizine for allergies)
- Single-ingredient cough suppressants (e.g., dextromethorphan, guaifenesin)
- Single-ingredient decongestants (e.g., pseudoephedrine, phenylephrine nasal spray)
- Nasal saline sprays for congestion
- Humidifiers for cough/congestion
Cost & Coverage
Average Cost:
Varies, typically $10-$25 per 120-240 mL bottle
Generic Available:
Yes
Insurance Coverage:
OTC (Out-of-pocket, or may be covered by FSA/HSA)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.