Fiber-Lax 625mg Tablets
It is used to treat constipation.
Drug Class
Laxative, Bulk-forming
Pharmacologic Class
Synthetic polyacrylic resin
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Polycarbophil is a type of fiber that works like a sponge in your intestines. It soaks up water to make your stool softer and bulkier, which helps you have a bowel movement more easily. It can also help make watery stools more solid if you have diarrhea.
How to Use This Medicine
Taking Your Medication Correctly
To use this medication safely and effectively, follow your doctor's instructions and read all the information provided. Take your medication with a full glass of water, as directed.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on proper disposal. You may also want to explore local drug take-back programs.
Missing a Dose
If you take this medication on a regular schedule, take a 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 normal 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 use this medication safely and effectively, follow your doctor's instructions and read all the information provided. Take your medication with a full glass of water, as directed.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on proper disposal. You may also want to explore local drug take-back programs.
Missing a Dose
If you take this medication on a regular schedule, take a 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 normal 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 (at least 8 ounces with each dose and throughout the day) to prevent the medication from swelling in your throat or esophagus and causing choking or obstruction.
- Maintain a balanced diet rich in fiber (fruits, vegetables, whole grains).
- Engage in regular physical activity to promote bowel regularity.
- Do not take this medication if you have difficulty swallowing or have any narrowing of the esophagus or bowel.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
1250 mg (2 tablets) orally 1 to 4 times daily, or as directed by a physician. Each dose should be taken with at least 8 ounces (240 mL) of water or other liquid.
Dose Range:
625 - 5000 mg
Condition-Specific Dosing:
constipation:
Initial: 1250 mg once daily; Titrate up to 5000 mg daily in divided doses as needed for effect.
diarrhea:
1250 mg after each loose bowel movement, not to exceed 7500 mg in 24 hours.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
6-11 years: 625 mg (1 tablet) orally 1 to 3 times daily, or as directed by a physician. Each dose should be taken with at least 8 ounces (240 mL) of water or other liquid.
Adolescent:
12 years and older: Same as adult dosing.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Dialysis:
No adjustment needed; not systemically absorbed.
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Pharmacology
Mechanism of Action
Polycarbophil is a hydrophilic polyacrylic resin that absorbs water in the gastrointestinal tract, forming a bulky, emollient gel. This increased bulk stimulates peristalsis and promotes a more natural bowel movement. It also helps to solidify loose stools by absorbing excess water, making it useful for both constipation and diarrhea.
Pharmacokinetics
Absorption:
Bioavailability:
Negligible (<1%)
Tmax:
Not applicable (not absorbed)
FoodEffect:
No significant effect, but should be taken with adequate fluid.
Distribution:
Vd:
Not applicable (not absorbed)
ProteinBinding:
Not applicable (not absorbed)
CnssPenetration:
No
Elimination:
HalfLife:
Not applicable (not absorbed)
Clearance:
Not applicable (not absorbed)
ExcretionRoute:
Fecal (unchanged)
Unchanged:
>99%
Pharmacodynamics
OnsetOfAction:
12 to 72 hours
PeakEffect:
Not applicable (gradual effect)
DurationOfAction:
As long as regular dosing continues
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
Chest pain or pressure
Upset stomach or vomiting
Stomach pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people do not experience any side effects or only have mild ones. If you have any side effects that bother you or do not go away, contact your doctor for advice. Not all possible side effects are listed here. If you have questions or concerns about side effects, discuss them with your doctor.
Reporting Side Effects
If you experience any side effects, you can report them to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor is also available to provide guidance on managing side effects.
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
Chest pain or pressure
Upset stomach or vomiting
Stomach pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people do not experience any side effects or only have mild ones. If you have any side effects that bother you or do not go away, contact your doctor for advice. Not all possible side effects are listed here. If you have questions or concerns about side effects, discuss them with your doctor.
Reporting Side Effects
If you experience any side effects, you can report them to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor is also available to provide guidance on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Chest pain, vomiting, or difficulty swallowing after taking the product.
- New or worsening abdominal pain, bloating, or gas.
- Rectal bleeding.
- Failure to have a bowel movement after using the laxative.
- Symptoms of bowel obstruction (e.g., severe abdominal pain, nausea, vomiting, inability to pass gas or stool).
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 experience difficulty swallowing.
* If you have a history of certain health issues, including:
+ Bowel blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that persist for more than 2 weeks
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help determine whether it is safe to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust 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 experience difficulty swallowing.
* If you have a history of certain health issues, including:
+ Bowel blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that persist for more than 2 weeks
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help determine whether it is safe to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust 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.
To minimize the risk of choking, it is crucial to take this drug with a sufficient amount of fluids. If not taken with enough fluids, the drug may expand and obstruct your throat, potentially leading to choking. If you have concerns, discuss them with your doctor.
This medication can interfere with the absorption of other drugs, reducing their effectiveness. If you are taking other medications, consult with your doctor or pharmacist to determine if you should take them at a different time than this drug.
Do not use this medication for more than 1 week without explicit instructions from your doctor to do so.
If you experience rectal bleeding or do not have a bowel movement after using this drug, consult with your doctor promptly.
Unless advised by your doctor, avoid using other laxatives or stool softeners in conjunction with this medication.
If you are pregnant, planning to become pregnant, or are breast-feeding, inform 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 choking, it is crucial to take this drug with a sufficient amount of fluids. If not taken with enough fluids, the drug may expand and obstruct your throat, potentially leading to choking. If you have concerns, discuss them with your doctor.
This medication can interfere with the absorption of other drugs, reducing their effectiveness. If you are taking other medications, consult with your doctor or pharmacist to determine if you should take them at a different time than this drug.
Do not use this medication for more than 1 week without explicit instructions from your doctor to do so.
If you experience rectal bleeding or do not have a bowel movement after using this drug, consult with your doctor promptly.
Unless advised by your doctor, avoid using other laxatives or stool softeners in conjunction with this medication.
If you are pregnant, planning to become pregnant, or are breast-feeding, inform 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 abdominal distension
- Abdominal pain
- Bowel obstruction (rare, but possible with insufficient fluid intake)
What to Do:
Discontinue use. Ensure adequate fluid intake. If symptoms are severe or persistent, seek immediate medical attention. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Major Interactions
- Tetracyclines (e.g., doxycycline, minocycline): May bind to polycarbophil, reducing absorption. Separate administration by at least 2-3 hours.
- Digoxin: May bind to polycarbophil, reducing absorption. Separate administration by at least 2-3 hours.
- Oral anticoagulants (e.g., warfarin): May alter absorption or gut flora, potentially affecting INR. Monitor INR closely.
- Salicylates (e.g., aspirin): May bind to polycarbophil, reducing absorption. Separate administration by at least 2-3 hours.
Moderate Interactions
- Other oral medications: May reduce absorption of other orally administered drugs due to binding or increased transit time. Administer other medications at least 2 hours before or 2 hours after polycarbophil.
Monitoring
Routine Monitoring
Bowel movement frequency and consistency
Frequency: Daily
Target: Regular, soft, formed stools
Action Threshold: No bowel movement for 3-7 days, worsening constipation, or signs of impaction/obstruction.
Fluid intake
Frequency: Daily
Target: Adequate hydration (e.g., 8 glasses of water per day)
Action Threshold: Signs of dehydration or insufficient fluid intake with medication.
Symptom Monitoring
- Abdominal pain or cramping
- Bloating or gas
- Nausea or vomiting
- Rectal bleeding
- Difficulty swallowing
- Chest pain
- Signs of bowel obstruction (e.g., severe abdominal pain, inability to pass gas or stool)
Special Patient Groups
Pregnancy
Generally considered safe for use during pregnancy due to minimal systemic absorption. Often recommended as a first-line treatment for constipation in pregnant women.
Trimester-Specific Risks:
First Trimester:
Low risk
Second Trimester:
Low risk
Third Trimester:
Low risk
Lactation
Considered safe for use during breastfeeding as it is not systemically absorbed and therefore not excreted in breast milk.
Infant Risk:
Low risk
Pediatric Use
Use in children under 6 years old should only be under the direction of a physician. Ensure adequate fluid intake to prevent choking or impaction. Dosing for children 6-11 years is typically half the adult dose.
Geriatric Use
Generally safe for elderly patients. However, elderly patients may be more susceptible to dehydration or impaction if fluid intake is inadequate. Start with lower doses and ensure sufficient fluid intake. Assess for pre-existing bowel conditions or difficulty swallowing.
Clinical Information
Clinical Pearls
- Polycarbophil is effective for both constipation and diarrhea due to its water-absorbing properties.
- Always emphasize the importance of adequate fluid intake (at least 8 oz with each dose) to prevent esophageal or bowel obstruction.
- Onset of action is not immediate; patients should be advised that it may take 12-72 hours to produce a bowel movement.
- Not suitable for acute constipation or bowel obstruction; requires a functioning GI tract.
- Advise patients to separate administration from other oral medications by at least 2 hours to prevent reduced absorption of other drugs.
Alternative Therapies
- Other bulk-forming laxatives (e.g., psyllium, methylcellulose)
- Osmotic laxatives (e.g., polyethylene glycol, lactulose, magnesium hydroxide)
- Stool softeners (e.g., docusate sodium)
- Stimulant laxatives (e.g., bisacodyl, senna) - generally for short-term use
- Dietary fiber (e.g., fruits, vegetables, whole grains)
Cost & Coverage
Average Cost:
$5 - $20 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Generally not covered by insurance as an over-the-counter (OTC) product, unless prescribed by a physician and covered under specific plans (e.g., 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 for more information. If you have any questions or concerns about this 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 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.