Comparative Pharmacology
Head-to-head clinical analysis: DUPHALAC versus MIRALAX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DUPHALAC versus MIRALAX.
DUPHALAC vs MIRALAX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Duphalac (lactulose) is a synthetic disaccharide that is not absorbed in the gastrointestinal tract. It is metabolized by colonic bacteria to short-chain fatty acids (e.g., acetic, lactic, formic acids), which lower colonic pH. This acidic environment favors the conversion of ammonia (NH3) to ammonium (NH4+), which is trapped in the colon and excreted in feces, thereby reducing systemic ammonia absorption. Additionally, the osmotic effect of lactulose and its metabolites draws water into the colon, producing a laxative effect.
Polyethylene glycol 3350 (PEG 3350) is an osmotic laxative that works by retaining water in the stool through hydrogen bonding, increasing fecal water content and promoting bowel movements.
Oral: 15-30 mL once daily, may increase to 30-45 mL twice daily if needed. Rectal (enema): 150-300 mL as a single dose.
17 g (1 heaping tablespoon) dissolved in 4–8 oz of water, juice, soda, coffee, or tea, administered orally once daily. Maximum duration of use: 7 days.
None Documented
None Documented
Not applicable; systemic exposure is negligible. Orally administered lactulose acts locally in the colon.
Not applicable; polyethylene glycol 3350 is minimally absorbed and systemic half-life is not clinically relevant.
Lactulose is not absorbed from the gastrointestinal tract; it is excreted unchanged in feces (>99%).
Primarily excreted unchanged in feces (>90% of oral dose); negligible renal elimination (<0.1% recovered in urine).
Category C
Category C
Osmotic Laxative
Osmotic Laxative