Drug Interaction Report

GENERALLY AVOID: Drugs that directly affect the pituitary secretion of growth hormone (e.g., somatostatin, insulin, glucocorticoids, cyclooxygenase inhibitors such as aspirin and nonsteroidal anti-inflammatory drugs) and drugs that may transiently elevate growth hormone levels (e.g., clonidine, levodopa, insulin) may impact the accuracy of the macimorelin diagnostic test.

MANAGEMENT: Concomitant use of macimorelin with drugs affecting growth hormone levels should generally be avoided. A sufficient washout period following discontinuation of these drugs is recommended prior to macimorelin administration.

ADJUST DOSING INTERVAL: Food reduces the oral bioavailability of macimorelin. According to the product labeling, administration with a liquid meal decreased macimorelin peak plasma concentration (Cmax) and systemic exposure (AUC) by 55% and 49%, respectively, compared to administration under fasting conditions (i.e., for at least 8 hours).

MANAGEMENT: Macimorelin should be administered after fasting for at least 8 hours.

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.

The effect of grapefruit juice on the pharmacologic activity of caffeine is controversial. One report suggests that grapefruit juice increases the effect of caffeine. The proposed mechanism is inhibition of cytochrome P-450 metabolism of caffeine. However, a well-conducted pharmacokinetic/pharmacodynamic study did not demonstrate this effect. The clinical significance of this potential interaction is unknown.