Orange Juice Reduces Aspirin Absorption

[j.]

Influence of seven beverages on salicylate disposition in humans

OBJECTIVE:
Aspirin administered orally is one of most widely self-prescribed drugs to treat headaches or other pains. The aim of this study was to evaluate whether the influence of different beverages may be used to help in the ingestion of an aspirin tablet on the pharmacokinetic parameters of this drug.
METHOD:
This study was undertaken in five healthy volunteers. Seven beverages were tested: water, tea, coffee, orange juice, milk, beer and 40 degrees distilled alcohol. After plasma extraction, aspirin and salicylic acid were measured by HPLC with UV detection. The main pharmacokinetic parameters were determined by the compartimental method and drug disposition profiles by the Wagner-Nelson modified method.
RESULTS:
Elimination was not modified by any of the beverages but absorption was affected. Two opposing effects were observed: 40 degrees alcohol seemed to increase AUC and Cmax. Milk and beer seemed to decrease these parameters. With 40 degrees alcohol and tea, the amount absorbed and the disposition rate were higher. For milk and orange juice, the amount absorbed was lower and the disposition rate was unaffected. For beer, both the amount absorbed and the disposition rate increased. For coffee, both the amount absorbed and disposition rate were not significantly modified.
CONCLUSION:
The bioavailability of salicylates on the healthy volunteers in this study was significantly affected by concomitant administration of 40 degrees alcohol (spirit), beer and milk. The beverages seem to interfere with aspirin absorption and the drug disposition profile was modified.

 

[charlie]

I also read recently that aspirin reduces vitamin C absorption.

 

[j.]

I also read recently that aspirin reduces vitamin C absorption.

I would guess not enough to matter either way. Aspirin has some effects opposite to estrogen, and so does orange juice, so maybe what is reduced from the absorption of aspirin is compensated by the effects of OJ.

 

[DesertRat]

What I get from this is that taking aspirin with coffee is better than with milk or juice if you want to maximize absorption. And since aspirin slows some of the Phase II liver detox pathways, it seems getting the most out of a small dose makes sense.