Drug Interactions between fluoxetine / olanzapine and turmeric

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.

MONITOR: Turmeric may potentiate the bleeding risk associated with drugs that interfere with platelet function or coagulation. In vitro data suggest that curcumin, an active constituent of turmeric, may inhibit platelet-activating factor and platelet aggregation. Isolated case reports have also described increases in INR following initiation of turmeric-containing products in patients treated with a vitamin K antagonist such as warfarin. However, pharmacologic effects of turmeric preparations may be highly variable due to inconsistencies in formulation and potency of commercial herbal products.

MANAGEMENT: Caution is advised when turmeric-containing products are used concomitantly with drugs that affect hemostasis such as anticoagulants, antiplatelet agents, nonsteroidal anti-inflammatory drugs, serotonin reuptake inhibitors, and thrombolytic agents. Clinical and laboratory observation for hematologic complications is recommended.