Duphalac (lactulose) is primarily indicated for the treatment of constipation and for reducing elevated blood ammonia in patients with hepatic encephalopathy. As an osmotic laxative, it works by drawing water into the intestinal lumen, which softens stool and stimulates peristalsis. For short-term constipation relief, Duphalac is effective when dietary fiber, fluids, and exercise are insufficient. In chronic constipation, clinicians may recommend a regular dosing regimen to restore predictable bowel habits. For hepatic encephalopathy, lactulose reduces intestinal ammonia production and absorption by acidifying colonic contents and promoting the growth of non-urease-producing bacteria, which lowers systemic ammonia levels and can improve mental status in affected patients. These diverse uses make Duphalac a mainstay in both gastroenterology and hepatology care.
Dosage of Duphalac varies by indication, age, and patient response. For adults treating constipation, a common starting dose is 15–30 mL of the syrup once daily; dosing may be adjusted in 15 mL increments until 1–2 soft stools per day are achieved. In pediatric patients, dosing is weight-based—often 0.5–1 mL/kg/day initially—divided into one or two doses. For hepatic encephalopathy, higher or more frequent dosing is typical: adults may receive 30–45 mL three to four times daily until bowel movements are frequent and ammonia levels improve, with maintenance doses individualized based on clinical response. Duphalac can be taken with or without food; because it is a syrup, mix it with water or juice if palatability is an issue. Always follow the prescribing information or a clinician’s directions, and titrate to the minimal effective dose to reduce side effects like bloating and gas.
Before using Duphalac, disclose your full medical history to your healthcare provider. Important precautions include known hypersensitivity to lactulose or any syrup components, undiagnosed abdominal pain, nausea, vomiting, or suspected intestinal obstruction. Use with caution in patients with diabetes because Duphalac contains sugars that may affect glycemic control; check the label for carbohydrate content and consult a clinician to adjust diabetes medications if necessary. In elderly patients or those with electrolyte disturbances, prolonged use can lead to dehydration or imbalance—monitor fluid status and electrolytes during long-term therapy. Pregnant and breastfeeding patients should consult their healthcare provider; while lactulose is generally considered low risk because it is poorly absorbed systemically, decisions should balance expected benefits and potential risks. Finally, instruct caregivers and patients to maintain hydration and dietary fiber to enhance effectiveness and reduce dependence on medications alone.
Duphalac is contraindicated in patients with a known hypersensitivity to lactulose or any formulation excipients. It should not be used in cases of galactosemia or other inborn errors of carbohydrate metabolism because the syrup contains sugars that could worsen these conditions. Acute surgical abdomen, intestinal obstruction, or undiagnosed severe abdominal pain are also contraindications; using an osmotic laxative in obstructed bowel can worsen distention and risk perforation. Exercise caution when combining with other treatments that may alter intestinal motility or fluid balance, and avoid unsupervised long-term use without medical oversight, particularly where structural gastrointestinal disease is suspected.
Duphalac is generally well tolerated, but side effects can occur, especially during dose escalation. The most common adverse effects are gastrointestinal: bloating, flatulence, abdominal cramping, and increased bowel movement frequency. These symptoms often diminish after a few days as the gut adjusts. Diarrhea can happen if the dose is too high; reduce the dose until stool consistency improves. Rarely, prolonged or excessive use may cause electrolyte disturbances such as hypokalemia or metabolic acidosis in susceptible patients. Allergic reactions are uncommon but require immediate medical attention if they occur—signs include rash, itching, swelling, or difficulty breathing. Report persistent or severe side effects to your healthcare provider promptly so dosing can be adjusted or an alternative therapy can be considered.
Duphalac has few clinically significant systemic drug interactions because lactulose is minimally absorbed from the gut. However, interactions of practical importance may arise from effects on gastrointestinal transit and stool consistency. Agents that slow intestinal motility, such as opioid analgesics, may reduce Duphalac’s effectiveness and require dose adjustments or supplementary laxative strategies. Conversely, concomitant use with other laxatives can increase the risk of diarrhea and electrolyte imbalance. For patients on antibiotics or probiotics, changes in gut flora can influence lactulose’s mechanism in hepatic encephalopathy—monitor clinical response when antibiotics are initiated or stopped. In diabetic patients, be aware that the syrup contains sugars that may affect blood glucose and insulin dosing. Always tell your clinician about all prescription, over-the-counter medications, and supplements you take to evaluate potential interactions.
If you miss a scheduled dose of Duphalac, take it as soon as you remember unless it is almost time for your next dose. Do not double up doses to make up for a missed one. For chronic constipation, maintaining a regular daily routine helps stabilize bowel habits; occasional missed doses are unlikely to cause harm but may temporarily reduce effectiveness. In hepatic encephalopathy management, consistent dosing is more critical—missing doses can lead to increased ammonia levels and symptom recurrence. If doses are frequently missed, discuss strategies with your healthcare team to improve adherence or simplify the regimen.
An overdose of Duphalac is typically manifested by excessive laxative effect—profuse diarrhea, dehydration, and electrolyte imbalances such as low potassium. Management of overdose focuses on supportive care: stop Duphalac, rehydrate with oral fluids or intravenous fluids if necessary, and correct electrolyte disturbances. In severe cases, hospitalization may be required for monitoring and replacement therapy. If an overdose is suspected, seek medical attention promptly, especially in vulnerable populations like infants, the elderly, or those with cardiac or renal disease. Keep dosing devices accurate and out of reach of children to prevent accidental ingestion.
Store Duphalac syrup at room temperature, away from direct sunlight and heat sources, and keep the bottle tightly closed when not in use. Protect it from freezing. Keep the product out of reach of children and pets. Check the expiry date before use; do not use expired medication. If the syrup’s appearance, color, or odor changes, consult a pharmacist before continuing use. When disposing of unused Duphalac, follow local guidelines for medication disposal or return it to a pharmacy take-back program to prevent environmental contamination and accidental ingestion.
Duphalac is available by prescription in many jurisdictions, but regulated pathways may allow supervised access without a traditional written prescription in certain healthcare settings. Southwest Georgia Regional Medical Center offers a legal, structured solution for patients seeking Duphalac without a formal outside prescription: through an in-house medication access program, clinicians evaluate your needs during a consultation and, if appropriate, authorize and dispense lactulose with pharmacist counseling. This model ensures safe use by confirming indications, checking for contraindications and drug interactions, and providing dosing instructions and monitoring plans. Patients benefit from on-site education about side effects, hydration, and lifestyle measures to treat constipation or manage hepatic encephalopathy. If you’re interested in purchasing Duphalac without prescription, contact Southwest Georgia Regional Medical Center’s pharmacy services to learn about eligibility, consultation requirements, and how their supervised access option maintains compliance with state regulations while prioritizing patient safety.
Duphalac is the brand name for lactulose, a synthetic disaccharide osmotic laxative primarily used to treat constipation and to lower blood ammonia in hepatic encephalopathy. It is taken orally (or sometimes rectally) to soften stools, increase bowel movements, and reduce ammonia absorption in the gut.
Duphalac is not absorbed in the small intestine; it reaches the colon where gut bacteria ferment it into short-chain fatty acids. These acids draw water into the bowel (osmotic effect), increase stool bulk and motility, and acidify colonic contents, which converts ammonia (NH3) to ammonium (NH4+) and reduces ammonia absorption—helpful in hepatic encephalopathy.
Oral Duphalac typically starts working within 24–48 hours; for some people it may take up to 48–72 hours. Rectal administration (enema) produces a faster effect, often within a few hours. Speed depends on dose, individual bowel motility, and baseline diet/hydration.
For adults with constipation a common starting dose is 15–45 mL daily (approximately 10–30 g lactulose) in divided doses; adjust to produce 1–2 soft stools daily. Pediatric dosing is weight-dependent—often lower and carefully titrated; always follow pediatrician or product labeling. For hepatic encephalopathy, higher or more frequent dosing is used with monitoring.
Common side effects include bloating, flatulence, abdominal cramps, and nausea—usually mild and dose-related. Excessive dosing can cause diarrhea, dehydration, and electrolyte disturbances. Rare allergic reactions can occur.
Stop and seek medical help if you develop severe abdominal pain, signs of bowel obstruction (distention, severe pain, vomiting), severe diarrhea with signs of dehydration, allergic reaction (rash, swelling, breathing difficulty), or worsening confusion when used for hepatic encephalopathy.
Duphalac can be used long-term under medical supervision, especially for chronic constipation or recurrent hepatic encephalopathy. It does not cause physical dependence in the way stimulant laxatives can, but doses should be optimized and monitored to avoid chronic diarrhea or electrolyte imbalance.
Duphalac is generally considered relatively safe in pregnancy and lactation because it is minimally absorbed systemically; however, use should be discussed with a healthcare provider. Manage dosing to avoid dehydration and electrolyte issues.
Lactulose contains sugars (galactose and fructose components) and may have a small effect on blood glucose. Most people with diabetes can use it cautiously, but blood glucose should be monitored and a clinician consulted if there are concerns. In patients with strict carbohydrate restrictions, discuss alternatives.
Duphalac is contraindicated in patients with galactosemia because it contains galactose. Avoid in known hypersensitivity to lactulose. Use cautiously or avoid in acute surgical abdomen, suspected or established bowel obstruction, severe dehydration, or if electrolyte disturbances are present. Adjust use in renal impairment and monitor electrolytes when used long-term.
Take Duphalac orally, usually diluted in a glass of water, fruit juice, or milk if preferred; follow dosing instructions and titrate to effect. Store at room temperature away from direct sunlight and keep the bottle tightly closed. Shake well before use if indicated. Keep out of reach of children.
Duphalac has few direct drug interactions because it is not systemically absorbed; however, by accelerating transit it can reduce absorption of some oral medications. Also, chronic diarrhea from overuse can affect electrolyte balance and influence other drug therapies. Inform your clinician of all medications when starting lactulose.
Lactitol is another fermentable disaccharide osmotic laxative with a mechanism and clinical effects very similar to lactulose. Efficacy for constipation and minimal systemic absorption are comparable. Differences are mostly formulation, taste, and local availability; both can cause gas and bloating. Choice often depends on tolerance, cost, and availability.
PEG 3350 (e.g., Movicol, Miralax) is a non-fermentable osmotic agent that holds water in the stool. PEG often acts faster (12–72 hours) and is commonly preferred for chronic constipation due to good tolerability and less gas production. Lactulose may be chosen for hepatic encephalopathy because of its ammonia-lowering fermentation effect; PEG does not lower ammonia.
Sorbitol is another osmotic carbohydrate laxative that, like lactulose, is fermented in the colon and can cause gas and bloating. Onset and efficacy are broadly similar when given orally. Sorbitol is often used orally or as an enema; lactulose has the additional role in hepatic encephalopathy by reducing ammonia absorption.
Magnesium hydroxide is an osmotic saline laxative that typically works faster (a few hours to a day) and is effective for occasional constipation or bowel cleansing. Magnesium salts can cause electrolyte disturbances and are contraindicated or used cautiously in renal impairment. Lactulose is gentler for chronic use and is preferred when ammonia reduction is needed.
Magnesium citrate and sodium phosphate are saline laxatives commonly used for bowel prep before procedures; they act faster and are more aggressive, often producing bowel evacuation within hours. They are not suitable for routine chronic constipation management and carry higher risks of electrolyte shifts; lactulose is milder and better for daily management.
Bulk-forming laxatives (psyllium) work by absorbing water and increasing stool bulk, which stimulates peristalsis; they are a first-line option for many chronic constipation cases and have benefits for bowel regularity. Lactulose is faster to act in some patients and useful when softening is specifically needed or in hepatic encephalopathy. Bulk-formers require adequate fluid intake and may take longer (days) to be effective.
Docusate softens stool by reducing surface tension but may be less effective alone for significant constipation. Lactulose often provides more reliable stool softening and increased bowel movements. Combining agents is sometimes used, but clinicians tailor therapy to cause and severity of constipation.
Stimulant laxatives directly increase intestinal motility and typically act faster (6–12 hours oral); they can cause cramping and, with long-term use, risk of tolerance or electrolyte issues. Lactulose works by osmotic and fermentation mechanisms and is gentler for chronic use; stimulants are often reserved for refractory cases or short-term use.
Generic lactulose contains the same active ingredient and is pharmacologically equivalent to Duphalac if formulations and concentrations are comparable. Minor differences in excipients, taste, or concentration may affect dosing volumes; always check strength and dosing instructions when switching brands.
For hepatic encephalopathy, lactulose and rifaximin are commonly used together or sequentially. Lactulose reduces ammonia by altering gut flora metabolism and pH; rifaximin reduces ammonia-producing bacteria. Rifaximin can be effective as add-on therapy for recurrent encephalopathy. Choice and combination are determined by severity, response, cost, and clinician judgment.
Combination therapy is sometimes used: PEG for bulk stool evacuation and lactulose to maintain softer stools or address hepatic encephalopathy. Combining different classes can enhance efficacy but increases risk of diarrhea and electrolyte imbalance—use under medical guidance with monitoring.
PEG is often favored as first-line for chronic constipation because of strong evidence for efficacy, tolerability, and lower rates of gas/bloating. Duphalac remains a useful alternative, especially when ammonia reduction is needed or if PEG is not tolerated. Individual response varies; clinicians may trial one then switch if inadequate.
Yes—formulary coverage, price, flavor, and formulation (syrup vs powder) vary by country and brand. Lactulose formulations can taste sweet and produce gas; PEG is often tasteless powder dissolved in liquid. Cost and availability can influence choice when multiple clinically appropriate options exist.