Miralax 3350 Powder Packets
It is used to treat constipation.
Drug Class
Osmotic Laxative
Pharmacologic Class
Osmotic Agent
Pregnancy Category
Category C
FDA Approved
May 2006
DEA Schedule
Not Controlled
Overview
What is this medicine?
Miralax is an osmotic laxative that works by drawing water into your stool, making it softer and easier to pass. It helps relieve occasional constipation.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most out of your medication, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. When taking your medication, mix the powder with 1/2 to 1 cup (120 to 240 ml) of a liquid, such as water, juice, soda, coffee, or tea. Stir well to dissolve the powder completely before drinking. It's essential to check that the powder has fully dissolved before consumption; if you notice any clumps, do not drink the mixture. Additionally, avoid mixing the powder with starch-based thickeners.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding bathrooms and areas where children and pets may access it. Keep all medications in a safe and secure location. When it's time to dispose of your medication, throw away any unused or expired drugs. Do not flush medications down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist, as there may be drug take-back programs available in your area.
What to Do If You Miss a Dose
If you take your medication on a regular schedule, 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 dosing schedule. Do not take two doses at the same time or take extra doses. If you take your medication as needed, be sure not to take it more frequently than directed by your doctor.
To ensure you get the most out of your medication, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. When taking your medication, mix the powder with 1/2 to 1 cup (120 to 240 ml) of a liquid, such as water, juice, soda, coffee, or tea. Stir well to dissolve the powder completely before drinking. It's essential to check that the powder has fully dissolved before consumption; if you notice any clumps, do not drink the mixture. Additionally, avoid mixing the powder with starch-based thickeners.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding bathrooms and areas where children and pets may access it. Keep all medications in a safe and secure location. When it's time to dispose of your medication, throw away any unused or expired drugs. Do not flush medications down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, consult your pharmacist, as there may be drug take-back programs available in your area.
What to Do If You Miss a Dose
If you take your medication on a regular schedule, 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 dosing schedule. Do not take two doses at the same time or take extra doses. If you take your medication as needed, be sure not to take it more frequently than directed by your doctor.
Lifestyle & Tips
- Drink plenty of fluids (at least 6-8 glasses of water daily) while using this medication.
- Increase dietary fiber intake (fruits, vegetables, whole grains) if tolerated.
- Engage in regular physical activity to promote bowel regularity.
- Do not use for more than 7 days unless directed by a doctor.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
17 grams (one heaping tablespoon or one packet) of powder dissolved in 4 to 8 ounces of water, juice, soda, coffee, or tea once daily.
Dose Range:
17 - 17 mg
Condition-Specific Dosing:
chronic_constipation:
17 grams once daily for up to 7 days. Consult physician if longer use is needed.
Pediatric Dosing
Neonatal:
Not established (off-label use common, consult specialist)
Infant:
Not established (off-label use common, consult specialist)
Child:
Not established (off-label use common, typically 0.2-0.8 g/kg/day, consult specialist)
Adolescent:
Not established (off-label use common, typically 0.2-0.8 g/kg/day, consult specialist). For ages 17 and older, adult dosing applies.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Dialysis:
No adjustment needed; minimal systemic absorption.
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Pharmacology
Mechanism of Action
Polyethylene Glycol 3350 is an osmotic agent that causes water to be retained within the stool. It works by drawing water into the colon, which softens the stool and increases stool bulk, thereby stimulating bowel movements. It is not absorbed systemically.
Pharmacokinetics
Absorption:
Bioavailability:
<0.2%
Tmax:
Not applicable (minimal systemic absorption)
FoodEffect:
None
Distribution:
Vd:
Not applicable (minimal systemic absorption)
ProteinBinding:
Not applicable (minimal systemic absorption)
CnssPenetration:
No
Elimination:
HalfLife:
Not applicable (minimal systemic absorption)
Clearance:
Not applicable (minimal systemic absorption)
ExcretionRoute:
Fecal (unchanged)
Unchanged:
>99%
Pharmacodynamics
OnsetOfAction:
1 to 3 days
PeakEffect:
Not applicable (gradual effect)
DurationOfAction:
Variable, depends on continued use and individual bowel habits
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
Severe dizziness or fainting
Diarrhea
Rectal bleeding or rectal pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Loose, watery, or more frequent stools
Stomach pain or cramps
Gas
Bloating
* Upset stomach
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
Severe dizziness or fainting
Diarrhea
Rectal bleeding or rectal pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Loose, watery, or more frequent stools
Stomach pain or cramps
Gas
Bloating
* Upset stomach
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 abdominal pain, cramping, or bloating
- Nausea or vomiting
- Rectal bleeding or blood in stool (stop use and seek immediate medical attention)
- No bowel movement after 3 days of use
- Signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
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.
Certain health conditions, including:
+ Bowel obstruction or blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that last longer than 2 weeks
A diagnosis of irritable bowel syndrome (IBS)
Kidney disease or any other health problems that may affect your ability to take this medication
Additionally, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are currently taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems or conditions
This information will help your doctor determine whether it is safe for you to take this medication and ensure that it does not interact with any other medications or 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 and its symptoms.
Certain health conditions, including:
+ Bowel obstruction or blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that last longer than 2 weeks
A diagnosis of irritable bowel syndrome (IBS)
Kidney disease or any other health problems that may affect your ability to take this medication
Additionally, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are currently taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems or conditions
This information will help your doctor determine whether it is safe for you to take this medication and ensure that it does not interact with any other medications or 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 avoid potential complications, do not use this drug for more than 7 days unless your doctor has specifically instructed you to do so. Additionally, refrain from using other laxatives or stool softeners during treatment with this medication, unless your doctor advises otherwise. You may not experience the full effects of this drug immediately, as it may take a few days to achieve optimal results. If you are pregnant, planning to become pregnant, or are currently breast-feeding, be sure to discuss this with your doctor, as you will need to carefully weigh the benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe diarrhea
- Excessive fluid loss
- Electrolyte imbalances (e.g., low potassium, low sodium)
- Abdominal pain
- Nausea
- Vomiting
What to Do:
Discontinue use. Rehydrate with fluids and electrolytes. Seek medical attention if symptoms are severe or persistent. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Moderate Interactions
- Electrolyte-altering medications (e.g., diuretics, corticosteroids) if excessive use of PEG 3350 leads to fluid/electrolyte imbalance.
Minor Interactions
- Other oral medications (potential for decreased absorption if taken simultaneously, though generally not clinically significant due to PEG's rapid transit and minimal absorption)
Monitoring
Baseline Monitoring
Bowel habits and history of constipation
Rationale: To establish baseline and assess appropriateness of therapy.
Timing: Prior to initiation
Routine Monitoring
Frequency and consistency of bowel movements
Frequency: Daily
Target: Regular, soft, formed stools
Action Threshold: No bowel movement after 3 days, or persistent diarrhea/abdominal pain
Abdominal discomfort/bloating
Frequency: Daily
Target: Minimal to none
Action Threshold: Severe or worsening abdominal pain, distension
Hydration status
Frequency: Daily
Target: Adequate fluid intake
Action Threshold: Signs of dehydration (rare with normal use)
Symptom Monitoring
- Abdominal cramping
- Bloating
- Gas
- Nausea
- Diarrhea
- Rectal bleeding (seek immediate medical attention)
- Lack of bowel movement after 3 days of use
Special Patient Groups
Pregnancy
Generally considered low risk due to minimal systemic absorption. Often recommended as a first-line agent for constipation in pregnancy by medical guidelines. Consult a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Low risk
Second Trimester:
Low risk
Third Trimester:
Low risk
Lactation
Considered compatible with breastfeeding due to minimal systemic absorption by the mother, meaning negligible amounts are expected to pass into breast milk. L1 (safest) rating.
Infant Risk:
Low risk
Pediatric Use
Not officially approved for children under 17 years by the manufacturer, but widely used off-label and recommended by pediatric gastroenterologists for chronic constipation in children. Dosing should be determined by a healthcare professional based on weight and severity of constipation.
Geriatric Use
Generally safe and well-tolerated in elderly patients. Often preferred over stimulant laxatives due to lower risk of dependence and less cramping. Ensure adequate hydration.
Clinical Information
Clinical Pearls
- Miralax is an osmotic laxative, not a stimulant. It works gently over 1-3 days, so immediate relief should not be expected.
- It is tasteless and dissolves completely in most liquids, making it easy to administer.
- Encourage patients to maintain adequate fluid intake while using PEG 3350 to maximize its effectiveness and prevent dehydration.
- For chronic constipation, it can be used long-term under medical supervision, unlike stimulant laxatives.
- Advise patients to separate administration from other oral medications by at least 2 hours if possible, although clinically significant interactions are rare.
Alternative Therapies
- Fiber supplements (e.g., psyllium, methylcellulose)
- Stool softeners (e.g., docusate sodium)
- Stimulant laxatives (e.g., bisacodyl, senna) - for short-term use only
- Saline laxatives (e.g., magnesium hydroxide)
- Lubricant laxatives (e.g., mineral oil)
- Prescription osmotic laxatives (e.g., lactulose, sorbitol)
- Chloride channel activators (e.g., lubiprostone)
- Guanylate cyclase-C agonists (e.g., linaclotide, plecanatide)
Cost & Coverage
Average Cost:
$15 - $30 per 17 oz (482g) bottle or 30 packets
Generic Available:
Yes
Insurance Coverage:
Often OTC, may not be covered by insurance unless prescribed or for specific conditions. Some FSA/HSA eligible.
General Drug Facts
If your symptoms or health issues persist or worsen, it is 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 it's a good idea to check with your pharmacist. 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 information about the medication taken, the amount, and the time it happened.