Drug Interaction Report

MONITOR: Bowel cleansing as well as overuse of certain laxatives may cause electrolyte loss and increase the risk of torsade de pointes ventricular arrhythmia in patients treated with drugs that prolong the QT interval. Electrolyte disturbances including hypokalemia and hypomagnesemia have been reported with laxative abuse and are known risk factors for torsade de pointes associated with QT interval prolongation.

MANAGEMENT: Patients treated with drugs that prolong the QT interval should exercise caution when self-medicating with laxatives. The recommended dosage and duration of use should not be exceeded. Patients treated with lactulose for more than six months should be monitored periodically for electrolyte imbalance. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of paliperidone. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

Administration with food may increase the bioavailability of paliperidone from the extended release tablets. In healthy ambulatory subjects, administration of a 12 mg paliperidone extended release tablet with a standard high-fat/high-caloric meal resulted in 60% and 54% increases, respectively, in the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of paliperidone compared to administration under fasting conditions. The clinical significance of these changes is unknown.

MANAGEMENT: Patients receiving paliperidone should be advised to avoid the consumption of alcohol. Since clinical trials establishing the safety and efficacy of paliperidone were carried out without regard to the timing of meals, presumably paliperidone may be administered with or without food.