Pres Gen Liquid
It is used to treat nose stuffiness.It is used to thin mucus so it can be taken from the body by coughing.It is used to relieve coughing.
Drug Class
Expectorant, Antitussive, Decongestant
Pharmacologic Class
Guaiacolate, NMDA receptor antagonist, Alpha-1 adrenergic agonist
Pregnancy Category
Category C
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
This medicine is a combination of three ingredients: an expectorant (guaifenesin) to help loosen mucus and make coughs more productive, a cough suppressant (dextromethorphan) to reduce the urge to cough, and a decongestant (phenylephrine) to relieve stuffy nose. It's used to treat cough and congestion due to colds or allergies.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most benefit from your medication, 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, but if it causes stomach upset, take it with food to help minimize discomfort.
It's essential to stay hydrated while taking this medication, so drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. When taking the liquid form of this medication, measure your dose accurately using the measuring device provided with the medication. If no device is included, ask your pharmacist for a suitable measuring tool.
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 by your doctor or pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist, who may be aware of drug take-back programs in your area.
What to Do If You Miss a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing 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 ensure you get the most benefit from your medication, 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, but if it causes stomach upset, take it with food to help minimize discomfort.
It's essential to stay hydrated while taking this medication, so drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. When taking the liquid form of this medication, measure your dose accurately using the measuring device provided with the medication. If no device is included, ask your pharmacist for a suitable measuring tool.
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 by your doctor or pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist, who may be aware of drug take-back programs in your area.
What to Do If You Miss a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing 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
- Drink plenty of fluids to help loosen mucus.
- Avoid activities requiring mental alertness until you know how the medication affects you, as it may cause dizziness or drowsiness.
- Do not exceed the recommended dose.
- Do not use with other cough, cold, or flu medicines containing similar ingredients.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
10 mL every 4 hours as needed
Dose Range:
10 - 20 mg
Condition-Specific Dosing:
maximumDailyDose:
60 mL (6 doses) in 24 hours
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not recommended for children under 4 years; consult physician for children 4-11 years (dose varies by product concentration and weight). Typical dose for 6-11 years: 5 mL every 4 hours.
Adolescent:
10 mL every 4 hours as needed (for ages 12 years and older)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended, use with caution
Moderate:
Use with caution, consider reduced frequency or dose
Severe:
Use with caution, consider reduced frequency or dose; consult physician
Dialysis:
Not well studied; use with caution and monitor for adverse effects
Hepatic Impairment:
Mild:
No specific adjustment recommended, use with caution
Moderate:
Use with caution, consider reduced frequency or dose
Severe:
Use with caution, consider reduced frequency or dose; consult physician
Pharmacology
Mechanism of Action
Guaifenesin acts as an expectorant by increasing the volume and decreasing the viscosity of respiratory tract secretions, facilitating their removal by ciliary action and coughing. Dextromethorphan is an antitussive that acts centrally on the cough center in the medulla to elevate the cough threshold. Phenylephrine is a direct-acting sympathomimetic amine that acts predominantly on alpha-1 adrenergic receptors in the respiratory tract mucosa, causing vasoconstriction and reducing nasal congestion.
Pharmacokinetics
Absorption:
Bioavailability:
Guaifenesin: Well absorbed; Dextromethorphan: Well absorbed; Phenylephrine: Poor oral bioavailability (approx. 38%) due to extensive first-pass metabolism
Tmax:
Guaifenesin: ~1 hour; Dextromethorphan: ~2 hours; Phenylephrine: ~1-2 hours
FoodEffect:
Generally not significant for absorption
Distribution:
Vd:
Guaifenesin: Not extensively studied; Dextromethorphan: Large (e.g., 5-6 L/kg); Phenylephrine: Not extensively studied
ProteinBinding:
Guaifenesin: Low (approx. 10%); Dextromethorphan: Not extensively bound; Phenylephrine: Not extensively bound
CnssPenetration:
Guaifenesin: Limited; Dextromethorphan: Yes (central action); Phenylephrine: Limited (peripheral action)
Elimination:
HalfLife:
Guaifenesin: ~1 hour; Dextromethorphan: ~2-4 hours (parent drug), ~10-20 hours (dextrorphan); Phenylephrine: ~2-3 hours
Clearance:
Guaifenesin: Rapid; Dextromethorphan: Varies by CYP2D6 phenotype; Phenylephrine: Rapid
ExcretionRoute:
Guaifenesin: Renal (metabolites); Dextromethorphan: Renal (unchanged drug and metabolites); Phenylephrine: Renal (metabolites and unchanged drug)
Unchanged:
Guaifenesin: <1%; Dextromethorphan: <10%; Phenylephrine: ~2.6% (oral)
Pharmacodynamics
OnsetOfAction:
Guaifenesin: ~30 minutes; Dextromethorphan: ~15-30 minutes; Phenylephrine: ~15-30 minutes
PeakEffect:
Guaifenesin: ~1 hour; Dextromethorphan: ~2 hours; Phenylephrine: ~1-2 hours
DurationOfAction:
Guaifenesin: ~4-6 hours; Dextromethorphan: ~4-6 hours; Phenylephrine: ~4 hours
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while 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, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
- Dizziness
- Feeling nervous and excitable
- Trouble sleeping
Additional Information on Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult your doctor. For medical advice regarding side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while 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, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
- Dizziness
- Feeling nervous and excitable
- Trouble sleeping
Additional Information on Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult your doctor. For medical advice regarding side effects, contact 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:
- Dizziness, nervousness, or sleeplessness
- Rapid heart rate or palpitations
- Significant increase in blood pressure
- Severe headache
- Nausea or vomiting that persists
- Rash or itching
- Difficulty breathing
- If cough or congestion worsens or lasts more than 7 days, or if accompanied by fever, rash, or persistent headache, consult a doctor.
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 you experienced, including any symptoms that occurred.
Respiratory issues, such as a cough that produces a significant amount 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 increase the risk of severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications may interact with this drug.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
* Your medical history, including any health problems you have
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 dose 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 you experienced, including any symptoms that occurred.
Respiratory issues, such as a cough that produces a significant amount 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 increase the risk of severely high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications may interact with this drug.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
* Your medical history, including any health problems you have
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 dose 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.
To minimize the risk of severe side effects, do not exceed the dosage prescribed by your doctor. Taking more than the recommended amount may increase your chance of experiencing severe side effects.
Adhere to the prescribed treatment duration and do not take this medication for longer than specified by your doctor.
Note that different brands of this medication may be suitable for children of varying ages. Before administering this drug to a child, consult with your doctor to ensure the appropriate brand and dosage are used.
If you are pregnant, planning to become pregnant, or are breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
To minimize the risk of severe side effects, do not exceed the dosage prescribed by your doctor. Taking more than the recommended amount may increase your chance of experiencing severe side effects.
Adhere to the prescribed treatment duration and do not take this medication for longer than specified by your doctor.
Note that different brands of this medication may be suitable for children of varying ages. Before administering this drug to a child, consult with your doctor to ensure the appropriate brand and dosage are used.
If you are pregnant, planning to become pregnant, or are breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or dizziness
- Nausea, vomiting, stomach pain
- Rapid or irregular heartbeat
- High blood pressure
- Hallucinations, confusion, agitation
- Seizures
- Difficulty breathing
- Urinary retention
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222.
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)
Major Interactions
- Serotonergic drugs (e.g., SSRIs, SNRIs, TCAs, triptans, tramadol, linezolid, St. John's Wort) with dextromethorphan (risk of serotonin syndrome)
- Other sympathomimetics (e.g., pseudoephedrine, ephedrine, stimulants) with phenylephrine (additive pressor effects, increased risk of cardiovascular events)
- Beta-blockers (non-selective) with phenylephrine (unopposed alpha-adrenergic effects, leading to severe hypertension)
- Tricyclic antidepressants (TCAs) with phenylephrine (potentiated pressor effects)
- Antihypertensive drugs (phenylephrine may reduce their effect)
Moderate Interactions
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine, amiodarone) with dextromethorphan (increased dextromethorphan levels, increased risk of adverse effects)
- Alcohol and other CNS depressants (additive CNS depression with dextromethorphan)
- Digoxin (phenylephrine may increase risk of arrhythmias)
Minor Interactions
- None commonly cited for significant clinical impact
Monitoring
Symptom Monitoring
- Effectiveness of cough suppression and expectoration
- Nasal congestion relief
- Signs of adverse effects (e.g., dizziness, nervousness, insomnia, headache, increased blood pressure, palpitations, nausea, vomiting)
- Signs of serotonin syndrome (agitation, confusion, rapid heart rate, dilated pupils, muscle rigidity, sweating, diarrhea, tremor)
- Signs of allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
Special Patient Groups
Pregnancy
Use with caution during pregnancy. While individual components are Category C, meaning animal studies have shown adverse effects or there are no adequate human studies, the overall risk is considered low for occasional use. Consult a healthcare provider before use.
Trimester-Specific Risks:
First Trimester:
Generally avoided if possible, especially decongestants, due to theoretical risks.
Second Trimester:
May be considered if benefits outweigh risks, under medical guidance.
Third Trimester:
Use with caution, especially phenylephrine, due to potential effects on maternal blood pressure and uterine blood flow.
Lactation
Use with caution during breastfeeding (Lactation Risk L3). Small amounts of ingredients may pass into breast milk. Phenylephrine may reduce milk supply. Consult a healthcare provider.
Infant Risk:
Potential for irritability, drowsiness, or mild CNS effects in the infant. Risk of reduced milk supply.
Pediatric Use
Not recommended for children under 4 years of age. For children 4-11 years, use only under the guidance of a healthcare professional and with products specifically formulated for children, as dosing is weight-based and concentrations vary. Overdosing can be serious.
Geriatric Use
Use with caution in elderly patients due to increased susceptibility to adverse effects, particularly from phenylephrine (e.g., increased blood pressure, CNS stimulation, urinary retention, exacerbation of glaucoma). Start with lower doses and monitor closely.
Clinical Information
Clinical Pearls
- Advise patients to read the label carefully and not to exceed the recommended dose, especially since many OTC products contain similar ingredients.
- Emphasize the critical interaction with MAOIs; patients must be explicitly warned about this.
- Counsel patients on the importance of hydration to maximize guaifenesin's expectorant effect.
- Warn about potential for drowsiness or dizziness, especially with dextromethorphan, and advise against driving or operating machinery if affected.
- Phenylephrine can cause elevated blood pressure and heart rate; caution in patients with hypertension, heart disease, or thyroid disorders.
- Not effective for chronic cough due to smoking, asthma, or emphysema unless directed by a doctor.
Alternative Therapies
- Single-ingredient Guaifenesin (e.g., Mucinex)
- Single-ingredient Dextromethorphan (e.g., Delsym)
- Single-ingredient Phenylephrine (e.g., Neo-Synephrine nasal spray)
- Saline nasal sprays for congestion
- Humidifiers for cough and congestion
- Honey for cough relief
Cost & Coverage
Average Cost:
Varies widely per bottle
Generic Available:
Yes
Insurance Coverage:
OTC (Over-The-Counter) - generally not covered by prescription insurance, but may be eligible for FSA/HSA.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the overdose, including the medication taken, the amount, and the time it occurred.