Drug Interactions between fluoxetine / olanzapine and sodium oxybate

GENERALLY AVOID: The central nervous system and respiratory depressant effects of sodium oxybate, which is the sodium salt of gamma hydroxybutyrate (GHB), may be potentiated by concomitant use of other agents with CNS depressant effects. An increased risk of serious adverse reactions such as respiratory depression, hypotension, profound sedation, syncope, coma, and even death should be considered.

MANAGEMENT: Concomitant use of sodium oxybate with other CNS depressants should be avoided whenever possible. Otherwise, close monitoring and/or dosage reductions should be considered. If short-term use of a CNS depressant is required (e.g., post- or perioperative opioid), a temporary interruption of sodium oxybate therapy may be appropriate. All patients treated with sodium oxybate should be advised not to drive, operate machinery, or engage in potentially hazardous activities requiring mental alertness and motor coordination for at least 6 hours after taking the second nightly dose of sodium oxybate and until they know how the medication affects them.

GENERALLY AVOID: The central nervous system and respiratory depressant effects of sodium oxybate, which is the sodium salt of gamma hydroxybutyrate (GHB), may be potentiated by concomitant use of other agents with CNS depressant effects. An increased risk of serious adverse reactions such as respiratory depression, hypotension, profound sedation, syncope, coma, and even death should be considered.

MANAGEMENT: Concomitant use of sodium oxybate with other CNS depressants should be avoided whenever possible. Otherwise, close monitoring and/or dosage reductions should be considered. If short-term use of a CNS depressant is required (e.g., post- or perioperative opioid), a temporary interruption of sodium oxybate therapy may be appropriate. All patients treated with sodium oxybate should be advised not to drive, operate machinery, or engage in potentially hazardous activities requiring mental alertness and motor coordination for at least 6 hours after taking the second nightly dose of sodium oxybate and until they know how the medication affects them.

MONITOR: It is uncertain whether olanzapine causes clinically significant prolongation of the QT interval. In pooled studies of adults as well as pooled studies of adolescents, there were no significant differences between olanzapine and placebo in the proportion of patients experiencing potentially important changes in ECG parameters, including QT, QTcF (Fridericia-corrected), and PR intervals. In clinical trials, clinically meaningful QTc prolongations (QTcF >=500 msec at any time post-baseline in patients with baseline QTcF <500 msec) occurred in 0.1% to 1% of patients treated with olanzapine, with no significant differences in associated cardiac events compared to placebo. Published studies have generally reported no significant effect of olanzapine on QTc interval, although both QTc prolongation and QTc shortening have also been reported. There have been a few isolated case reports of QT prolongation in patients receiving olanzapine. However, causality is difficult to establish due to confounding factors such as concomitant use of drugs that cause QT prolongation and underlying conditions that may predispose to QT prolongation (e.g., hypokalemia, congenital long QT syndrome, preexisting conduction abnormalities).

MANAGEMENT: Some authorities recommend caution when olanzapine is used with drugs that are known to cause QT prolongation. ECG monitoring may be advisable in some cases, such as in patients with a history of cardiac arrhythmias or congenital or family history of long QT syndrome. 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.