Drug Interactions between buspirone and calcium oxybate / magnesium oxybate / potassium oxybate / sodium oxybate

CONTRAINDICATED: Alcohol may potentiate the central nervous system and respiratory depressant effects of sodium oxybate, which is the sodium salt of gamma hydroxybutyrate (GHB). An increased risk of serious adverse reactions such as respiratory depression, hypotension, profound sedation, syncope, coma, and even death should be anticipated.

ADJUST DOSING INTERVAL: Food may delay the absorption and significantly decrease the bioavailability of sodium oxybate. When sodium oxybate was administered immediately after a high-fat meal, the time to reach peak plasma concentration (Tmax) increased from 0.75 hour to 2 hours, the peak plasma concentration (Cmax) decreased by a mean of 59%, and the systemic exposure (AUC) decreased by a mean of 37%.

MANAGEMENT: The concomitant use of sodium oxybate with alcohol is considered contraindicated. The first dose of sodium oxybate should be taken at least 2 hours after a meal to ensure maximal absorption.

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

ADJUST DOSING INTERVAL: In a small, randomized, crossover study, the consumption of large amounts of grapefruit juice (compared to water) was associated with significantly increased plasma buspirone concentrations, slightly prolonged elimination half-lives, and delayed times to reach peak drug concentration. The perceived pharmacodynamic effect of buspirone, as measured by subjective drowsiness and overall subjective drug effect, was also enhanced by grapefruit juice. These alterations may stem from the delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Patients receiving buspirone should be advised to avoid consumption of alcohol. Patients also should preferably avoid the consumption of large amounts of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels. If this is not possible, the buspirone dose should be taken at least 2 hours before or 8 hours after grapefruit or grapefruit juice. Monitoring for increased CNS depression is recommended.