Drug Interactions between quetiapine and Xadago

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Grapefruit juice and/or grapefruit may increase the plasma concentrations of quetiapine. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice but has been reported for other CYP450 3A4 inhibitors. For example, in 12 healthy volunteers, administration of a single 25 mg dose of quetiapine with the potent CYP450 3A4 inhibitor ketoconazole (200 mg once daily for 4 days) increased mean quetiapine peak plasma concentration (Cmax) and systemic exposure (AUC) by 3.4- and 6.2-fold, respectively, and decreased mean oral clearance by 84%. In general, the effects of grapefruit products are concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. High plasma levels of quetiapine may increase the risk and/or severity of serious adverse effects such as extrapyramidal symptoms, tardive dyskinesia, hyperglycemia, dyslipidemia, hyperprolactinemia, orthostatic hypotension, blood pressure increases (in children and adolescents), priapism, QT prolongation, cognitive and motor impairment, dysphagia, heat-related illnesses due to disruption of body temperature regulation, and symptoms of serotonin syndrome (e.g., mental status changes such as irritability, altered consciousness, confusion, hallucination, and coma; autonomic dysfunction such as tachycardia, hyperthermia, diaphoresis, shivering, blood pressure lability, and mydriasis; neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea).

Food may have varying effects on the absorption of quetiapine from immediate-release versus prolonged-release formulations. In a study examining the effects of food on the bioavailability of quetiapine, a high-fat meal was found to produce statistically significant increases in the quetiapine prolonged release Cmax and AUC of approximately 50% and 20%, respectively. It cannot be excluded that the effect of a high fat meal on the formulation may be larger. In comparison, a light meal had no significant effect on the Cmax or AUC of quetiapine.

Quetiapine may potentiate the cognitive and motor effects of alcohol. The mechanism is likely related to the primary central nervous system effects of quetiapine.

MANAGEMENT: According to the manufacturer, consumption of grapefruit juice should be avoided during treatment with quetiapine. Quetiapine immediate-release tablets may be taken with or without food. It is recommended that quetiapine prolonged release is taken once daily without food or with a light meal. Consumption of alcohol should be limited and used with caution while taking quetiapine.

Safinamide may be taken with or without food. While there is no need to strictly avoid most foods and beverages that contain tyramine (usually aged, fermented, cured, smoked, or pickled foods such as air-dried and fermented meats or fish, aged cheeses, most soybean products, yeast extracts, red wine, beer, and sauerkraut) during treatment with safinamide, certain foods such as some of the aged cheeses (for example, Boursault, Liederkrantz, Mycella, and Stilton) and pickled herring may contain very high amounts of tyramine and should generally be avoided if possible. Consumption of very high levels of tyramine (greater than 150 mg) while on safinamide treatment may lead to dangerous increases in your blood pressure, a condition known as hypertensive crisis. Talk to your doctor or pharmacist if you are uncertain about what foods, if any, to avoid. You should seek immediate medical attention if you experience sudden and severe headache, blurred vision, confusion, seizures, chest pain, nausea or vomiting, sudden numbness or weakness (especially on one side of the body), speech difficulties, fever, sweating, lightheadedness, and/or fainting during treatment with safinamide, as these may be signs and symptoms of a hypertensive crisis. Do not take larger doses or use the medication more frequently than prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.