Summary

Linezolid and rasagiline have a significant drug interaction that can lead to serotonin syndrome due to their combined effects on serotonin metabolism. This interaction is considered contraindicated and requires careful management or alternative therapy selection.

Introduction

Linezolid is an oxazolidinone antibiotic used to treat serious gram-positive bacterial infections, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci. Rasagiline is a selective monoamine oxidase type B (MAO-B) inhibitor prescribed for the treatment of Parkinson's disease, either as monotherapy in early-stage disease or as adjunctive therapy with levodopa in advanced stages.

Mechanism of Interaction

The interaction between linezolid and rasagiline occurs through their combined effects on monoamine oxidase enzymes and serotonin metabolism. Linezolid acts as a reversible, non-selective monoamine oxidase inhibitor, while rasagiline selectively inhibits MAO-B at therapeutic doses. When used together, these medications can significantly reduce the metabolism of serotonin and other monoamines, leading to excessive accumulation of these neurotransmitters and potentially triggering serotonin syndrome.

Risks and Symptoms

The primary risk of combining linezolid and rasagiline is the development of serotonin syndrome, a potentially life-threatening condition characterized by altered mental status, autonomic instability, and neuromuscular abnormalities. Symptoms may include confusion, agitation, hyperthermia, diaphoresis, tremor, muscle rigidity, and cardiovascular instability. The risk is particularly elevated in patients taking additional serotonergic medications or those with compromised drug metabolism. This interaction is classified as major and is generally considered contraindicated.

Management and Precautions

When possible, avoid concurrent use of linezolid and rasagiline. If linezolid treatment is absolutely necessary in a patient taking rasagiline, consider discontinuing rasagiline at least 14 days before starting linezolid to allow adequate washout time. Alternative antibiotics should be strongly considered for treating the infection. If concurrent use cannot be avoided, implement intensive monitoring for signs and symptoms of serotonin syndrome, including frequent assessment of mental status, vital signs, and neurological function. Patients and caregivers should be educated about the warning signs of serotonin syndrome and instructed to seek immediate medical attention if symptoms develop.

Linezolid interactions with food and lifestyle

Linezolid has significant interactions with tyramine-rich foods that require careful dietary restrictions. Patients taking linezolid should avoid or limit foods high in tyramine including aged cheeses, cured meats, fermented foods, red wine, beer, and certain vegetables like sauerkraut. Consuming large amounts of tyramine while on linezolid can lead to dangerous increases in blood pressure (hypertensive crisis). Additionally, linezolid can interact with foods and beverages containing high amounts of caffeine, potentially causing increased blood pressure and heart rate. Patients should limit caffeine intake from coffee, tea, energy drinks, and chocolate while taking this medication. Alcohol should be avoided or used with extreme caution as it may increase the risk of side effects and can interact with linezolid's mechanism of action.

Rasagiline interactions with food and lifestyle

Rasagiline requires significant dietary restrictions due to its mechanism as a monoamine oxidase inhibitor (MAO-B). Patients must avoid foods high in tyramine, including aged cheeses, cured meats, fermented foods, aged or smoked fish, sauerkraut, soy sauce, and certain alcoholic beverages (particularly red wine, beer, and aged spirits). Consuming tyramine-rich foods while taking rasagiline can lead to dangerous hypertensive crisis. Alcohol consumption should be limited or avoided, as it may increase the risk of side effects and can interact with the medication's effects on blood pressure. Patients should also avoid excessive amounts of caffeine, as rasagiline may enhance caffeine's stimulant effects. Additionally, patients should inform their healthcare provider about all dietary supplements, particularly those containing tyramine or stimulants, before use with rasagiline.