However, the use of lactulose by women who are pregnant or may become pregnant requires that the potential benefits be weighed against the potential risks. There have been conflicting reports about the concomitant use of neomycin and lactulose syrup. Theoretically, the elimination of certain colonic bacteria by neomycin and possibly other anti-infective agents may interfere with the desired degradation of lactulose and thus prevent the acidification of colonic contents. Other laxatives probably should not be used during the initial phase of therapy for portal-systemic encephalopathy since the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved. Initial dosing may produce flatulence and intestinal cramps, which are usually transient.
Excessive dosage can lead to diarrhea.
Nausea has been reported. Diarrhea and abdominal cramps may be controlled by a reduction of the dosage. The dosage may be adjusted every day or two to produce 2 or 3 soft stools daily. If desired, hourly doses of 30 to 45 mL of lactulose may be used to induce more rapid laxation as indicated in the initial phase of the therapy of portal-systemic encephalopathy. When the laxative effect has been achieved, the dose of lactulose may then be reduced to the recommended daily dose.