Psyllium

Introduction Overview

Generic Name

psyllium

Brand Name

Hydrocil, Laxmar, Natural Fiber Therapy, Fiberall, Konsyl, Metamucil, Reguloid, Syllact, Modane Bulk, V-Lax, Perdiem Fiber Powder, Konsyl-Orange, Konsyl-D, Maalox Daily Fiber Therapy, Cilium, Alramucil, Serutan, Laxative Natural, Genfiber, Fiber Eze, Konsyl for Kids, Laxmar Orange, Metamucil Orange Smooth Texture, Metamucil Orange Smooth Texture Sugar Free, Metamucil Unflavored Coarse Milled Original, Fiber Therapy, Metamucil Orange Coarse Milled Original, Metamucil Unflavored Smooth Texture, Metamucil Berry Burst Smooth Texture, Laxmar Sugar Free, Konsyl Orange Sugar-free, Metamucil Pink Lemonade Smooth Texture Sugar-Free, Metamucil Original Texture Regular, Metamucil MultiHealth Fiber, Metamucil MultiHealth Fiber Sugar-free, Reguloid Sugar Free, Reguloid Orange Smooth, Reguloid Sugar Free Orange Smooth, Konsyl Sugar Free Orange With Stevia, Metamucil Thins Chocolate, Metamucil Thins Cinnamon Spice, Metamucil Thins Apple Crisp, Metamucil Kids Thins, Daily Fiber Sugar-Free, Onelax Fiber Therapy, Reguloid Sugar Free Unflavored Smooth

Dosage Form

oral capsule, oral powder for reconstitution, oral wafer

Drug Class

Laxatives

Pharmacokinetics

Absorption:
Psyllium is a non-absorbable bulk-forming fiber derived from the husks of Plantago ovata seeds. It is not absorbed in the gastrointestinal tract, as it remains intact throughout digestion. Upon oral administration, psyllium absorbs water in the intestines, swelling to form a viscous gel that increases stool bulk and promotes peristalsis. Because it is not systemically absorbed, the drug acts locally within the GI tract to influence bowel consistency and motility.

Distribution:
Since psyllium is not absorbed into the systemic circulation, it does not distribute to tissues or organs. Its therapeutic effect is confined to the lumen of the gastrointestinal tract. The formed gel modulates the physical properties of intestinal contents, enhancing fecal water content and stimulating mechanoreceptors in the bowel wall to facilitate bowel movements.

Metabolism:
Psyllium is largely resistant to enzymatic degradation in the small intestine but undergoes partial fermentation by colonic bacteria. This fermentation produces short-chain fatty acids such as acetate, propionate, and butyrate, which may contribute to colonic health and possibly modest systemic effects such as improved lipid metabolism. The extent and rate of fermentation can vary among individuals based on gut microbiota composition.

Elimination:
Psyllium is eliminated primarily via feces unchanged, with the swollen gel and fiber mass being expelled during defecation. Due to its non-absorbable nature, there is no renal or hepatic clearance. The time course of elimination corresponds to normal transit times within the intestine, generally producing bowel movements within 12 to 72 hours after ingestion. Adequate hydration is essential to facilitate safe elimination and prevent impaction or obstruction risks.

Dosage Forms

Available Dosage Forms:
- Oral capsules available in strengths of 400 mg, 500 mg, and 525 mg.
- Oral powders for reconstitution including formulations such as 100% psyllium powder and combination weights like 2.4 g/3.7 g, 3.4 g/12 g, 3.4 g/5.2 g, 3.4 g/5.4 g, 3.4 g/5.8 g, and 3.4 g/7 g.
- Oral wafers available in 2 g and 2.5 g dosages.

Dosages for Adults and Adolescents:
- For constipation and irritable bowel syndrome, adults aged 19 to 50 years are generally advised a daily fiber intake of 38 g/day for males and 25 g/day for females.
- Typical dosing involves 1 to 2 rounded teaspoonfuls of powder, 1 to 2 packets, 1 to 2 wafers, or 5 to 6 capsules daily, taken orally with at least 8 ounces of fluid, 1 to 3 times per day.
- Dosage should be adjusted to incorporate total dietary fiber intake.

Specific Patient Populations:
- During pregnancy, the recommended daily fiber intake is generally 28 g/day and during lactation 29 g/day.
- Pediatric dosing for constipation varies by age: children 6 to 11 years may receive 1.25 to 15 g daily in divided doses; adolescents 12 years and older can be dosed similarly to adults (2.5 to 30 g daily divided).
- Psyllium use in children under 6 years is not recommended without medical advice.
- Hydration status must be closely monitored to avoid risk of esophageal or intestinal obstruction, especially in elderly or patients with swallowing difficulties.

Clinical guidelines emphasize administering psyllium with sufficient water to prevent choking or intestinal blockage. Dosage titration should be individualized based on response and tolerability.

Mechanism Of Action

Psyllium is a hydrophilic mucilloid derived from the husks of Plantago ovata seeds, functioning as a bulk-forming laxative. Upon ingestion and contact with water in the gastrointestinal tract, psyllium absorbs up to 10 to 20 times its weight in water, transforming into a viscous, gelatinous mass that increases stool bulk and moisture content. This bulk formation mechanically stimulates intestinal stretch receptors, enhancing peristalsis and promoting more regular bowel movements.

At the cellular level, the increased stool volume activates mechanoreceptors in the intestinal mucosa, leading to enhanced propulsive contractions and decreased intestinal transit time. The gel formed by psyllium also modulates the viscosity of the intestinal contents, which slows digestion and absorption, particularly of glucose and lipids, contributing to beneficial effects on glycemic control and cholesterol lowering.

Biochemically, psyllium’s soluble fiber content is partially fermented by colonic microbiota into short-chain fatty acids like acetate, propionate, and butyrate. These metabolites play important roles in colonic health, serving as an energy source for colonocytes, modulating inflammation, and potentially influencing systemic lipid metabolism, thereby contributing to cholesterol reduction observed in clinical studies.

Comparatively, unlike stimulant laxatives that act via direct irritation of the bowel wall, psyllium exerts a mechanical and hydrophilic action that is safer for long-term use and less likely to cause dependence or mucosal damage. Its efficacy in reducing LDL cholesterol and improving glycemic responses distinguishes it from other bulk-forming agents, supported by multiple randomized controlled trials demonstrating its clinical benefits beyond simple laxation.

Pharmacological Actions

Acts as a bulk-forming laxative by absorbing water and increasing stool bulk.
Stimulates intestinal peristalsis via mechanical activation of stretch receptors.
Partially fermented by colonic bacteria to produce beneficial short-chain fatty acids.
Slows glucose absorption by increasing intestinal content viscosity, aiding glycemic control.
Reduces serum LDL cholesterol by binding bile acids in the gut.
Improves bowel regularity and treats occasional constipation effectively.
Modulates intestinal transit time and stool consistency.
Exerts prebiotic effects supporting healthy gut microbiota balance.
Non-systemic with local action confined to the gastrointestinal tract.
Safer for long-term use compared to stimulant laxatives due to mechanical mode of action.
May aid in weight management by promoting satiety through increased bulk.
Decreases postprandial blood sugar spikes in diabetic patients.
Helps maintain intestinal mucosal health via fermentation products.
Minimal systemic absorption reducing risk of systemic adverse effects.
Compatible with other dietary approaches for digestive and cardiovascular health.

Therapeutic Or Clinical Uses

Treatment of occasional constipation and bowel irregularity in adults and children.
Management of irritable bowel syndrome (IBS) symptoms, particularly constipation-predominant IBS.
Dietary fiber supplementation to promote general digestive health and bowel regularity.
Adjunct therapy to lower elevated serum cholesterol levels in hypercholesterolemia when combined with diet.
Supportive therapy to promote heart health through LDL cholesterol reduction.
Part of comprehensive weight control programs by promoting a feeling of fullness.
May assist in blood sugar control in type 2 diabetes mellitus.
Prevention of diverticulitis flare-ups by maintaining regular bowel movements.
Used in gastrointestinal conditions requiring increased bulk without irritation, such as hemorrhoids or anal fissures.
Adjunct to treatment regimens for chronic diarrhea by bulk normalization.
Recommended for patients with low dietary fiber intake to prevent constipation.
Useful in elderly populations to maintain intestinal function.
Considered in treatment plans aiming at improving colonic health via prebiotic effects.
Beneficial in patients with colonoscopic bowel preparation protocols requiring increased stool bulk.
Employed in recovery following abdominal surgery to prevent postoperative ileus.

Side Or Adverse Effects

Bloating and flatulence due to increased intestinal fermentation.
Mild abdominal discomfort or cramping in some patients.
Minor changes in bowel habits including transient diarrhea or constipation if hydration is inadequate.
Potential for allergic reactions including rash, hives, or respiratory symptoms (rare).
Esophageal or intestinal obstruction if taken without adequate fluid intake.
Nausea or vomiting if insufficient water is consumed with the product.
Rare reports of bronchospasm or respiratory distress on inhalation of powder dust.
Rectal bleeding in case of prolonged constipation or underlying pathology needing medical evaluation.
Potential choking hazard from capsules especially in patients with swallowing difficulties.
Hypersensitivity reactions in individuals allergic to Plantago species.
Electrolyte disturbances if used excessively or in patients with dehydration.
Minimal systemic side effects due to poor systemic absorption.
Possible interference with absorption of concomitant oral medications if taken simultaneously.
Dry mouth or throat irritation if fluid intake is insufficient.
Rare cases of severe stomach pain warranting immediate discontinuation and medical assessment.

Precautions

Always take with adequate fluid (minimum 8 ounces) to prevent choking or intestinal obstruction.
Use cautiously in patients with difficulty swallowing or esophageal motility disorders.
Avoid in patients with a history of hypersensitivity to psyllium or related allergens.
Not recommended for children under 6 years without medical supervision.
Monitor for allergic reactions including rash, swelling, or respiratory difficulties.
Patients with sudden changes in bowel habits lasting over 2 weeks should seek medical advice before use.
Careful consideration required in patients with intestinal strictures, adhesions, or obstruction risks.
Avoid excessive or prolonged use; not recommended for more than 7 days consecutively without physician guidance.
May contain sugars, sodium, or phenylalanine; use caution in patients with diabetes, hypertension, or phenylketonuria.
Pregnancy and lactation: consult healthcare provider; dosage adjustments may be necessary.
Separate timing of psyllium and other oral medications by at least 2 hours to prevent absorption interference.
Avoid inhaling powder dust to prevent respiratory irritation or allergic reactions.
Educate patients on proper mixing of powder formulations to ensure safety and efficacy.
Discontinue use and consult a physician if constipation persists beyond 7 days, or if there is rectal bleeding or severe pain.
Store at room temperature, protected from moisture and heat to preserve product integrity.

Warnings

Do not use if allergic to psyllium or any components of the formulation.
May cause choking or esophageal obstruction if not taken with sufficient liquid.
Laxative overuse can lead to dependence and severe intestinal issues; limit use to under 7 consecutive days without medical advice.
Seek immediate medical attention if experiencing signs of allergic reaction such as hives, facial swelling, or difficulty breathing.
Report any rectal bleeding, severe abdominal pain, or prolonged constipation to a healthcare provider promptly.
Not intended for acute treatment of bowel obstruction or severe undiagnosed abdominal pain.
Avoid in patients with sudden or unexplained changes in bowel habits pending evaluation.
May interfere with absorption of other orally administered drugs; maintain timing intervals to prevent interaction.
Use caution in patients with known swallowing or esophageal motility problems.
If diarrhea develops, discontinue use and consult a healthcare professional.
Do not use as the sole therapy for chronic gastrointestinal diseases without physician supervision.
Pregnant or breastfeeding women should only use under medical guidance due to limited safety data.
Keep out of reach of children to prevent accidental ingestion or choking.
Inhalation of psyllium powder dust may cause allergic respiratory reactions; use in well-ventilated areas.
Patients with cardiovascular disease should use psyllium as part of a comprehensive management plan guided by a clinician.

Contraindication

Known hypersensitivity or allergy to psyllium or Plantago species.
Esophageal or intestinal obstruction or narrowing (strictures, adhesions) contraindicates bulk-forming fiber use.
Acute abdominal pain of unknown origin or suspected gastrointestinal obstruction.
Patients with difficulty swallowing or those unable to drink adequate fluids safely.
Immediate post-surgical states involving the gastrointestinal tract unless cleared by surgeon.
Patients with fecal impaction without prior disimpaction therapy.
Severe dehydration conditions where increased fiber may worsen electrolyte imbalance.
Individuals allergic to components present in certain formulations (such as flavorings or additives).
Do not use in children under 6 years of age without medical supervision due to choking risk.
Avoid in patients with sudden, severe gastrointestinal symptoms pending diagnosis.
Contraindicated in cases of gastrointestinal conditions requiring different therapeutic approaches (e.g., ischemic colitis).
Patients with phenylketonuria should avoid formulations containing phenylalanine.
Known intolerance to laxatives of the bulk-forming class.
Presence of acute inflammatory bowel disease flare-ups or severe colitis without medical clearance.

Drug Interactions

May reduce the absorption of concomitantly administered oral medications by forming a viscous barrier in the GI tract.
Avoid taking psyllium within 2 hours before or after other oral drugs to minimize bioavailability reduction.
Interactions reported with drugs such as digoxin, warfarin, carbamazepine, lithium, and certain diabetes medications.
Potential to interfere with absorption of fat-soluble vitamins (A, D, E, and K) with prolonged use.
May alter the efficacy of oral hypoglycemic agents by delaying carbohydrate absorption and glycemic response.
Co-administration with other laxatives should be done cautiously to avoid excessive GI motility or diarrhea.
Interaction potential with anticonvulsants due to altered gastrointestinal transit and absorption.
May reduce bioavailability of antibiotics like tetracyclines or fluoroquinolones via binding or delayed transit.
Possible decreased absorption of thyroid medications such as levothyroxine if taken simultaneously.
Fiber supplements including psyllium may decrease absorption of immunosuppressants (e.g., cyclosporine).
Consider timing of drugs with narrow therapeutic index to avoid subtherapeutic levels.
No significant systemic drug metabolism interactions due to non-absorbable nature of psyllium.
Concomitant use with diuretics may require monitoring of electrolyte balance if diarrhea occurs.
Herbal supplements and vitamins taken with psyllium should be timed to avoid absorption issues.
Advise patients to inform all healthcare providers about psyllium use to monitor for potential interactions.

Preparations Of The Drug

Oral capsules containing 400 mg, 500 mg, and 525 mg of psyllium husk.
Powder formulations for oral reconstitution available as 100% psyllium or blends with bulking agents in varying weights (e.g., 2.4 g/3.7 g, 3.4 g/12 g, 3.4 g/5.2 g, 3.4 g/5.4 g, 3.4 g/5.8 g, 3.4 g/7 g).
Oral wafers containing 2 g or 2.5 g doses offered as chewable or swallowable forms.
Flavor variants include unflavored, orange, berry burst, sugar-free, and multi-health fiber blends.
Available as bulk powders for reconstitution with water or juice, requiring thorough mixing and immediate consumption.
Formulations incorporating natural sweeteners such as stevia for sugar-free options.
Combination products with added vitamins, minerals, or other fiber types for enhanced therapeutic effects.
Psyllium thins and cookies as fiber-enriched snack forms for adjunct dietary supplementation.
Pediatric-specific formulations like smaller wafers and sugar-free flavored powders for improved palatability.
Available over-the-counter and by prescription, with packaging varying from single-dose sachets to multi-dose containers.
Specially designed formulations for diabetic or sodium-restricted patients.
Dry bulk formulations primarily intended for mixing immediately prior to dosing to maintain efficacy and safety.
Capsules designed to be swallowed individually to prevent choking risks.
Bulk fiber powders intended strictly for oral administration, avoiding inhalation to prevent allergic or respiratory reactions.
Packaging generally includes detailed patient instructions emphasizing hydration and proper use.