Thursday, July 14, 2011

What is theophylline? How does it interact with other drugs?


Vitamin B6


Effect: Supplementation Possibly Helpful




Theophylline appears to impair the normal conversion of vitamin B6
into the more active substance pyridoxal 5’-phosphate (PLP). These findings have led some researchers to suspect that some of the many side effects of theophylline could be caused, in part, by interference with B6 activity. Indeed, one study found that B6 supplements might help reduce theophylline-induced tremors.




St. John’s Wort


Effect: Possible Interference with Action of Drug


Evidence suggests that the herb St. John’s wort can lower blood levels of theophylline, making it less effective.




Cayenne


Effect: Possible Increased Risk of Toxicity


Oral cayenne might increase the absorption of theophylline, which could lead to an increased risk of theophylline toxicity.




Ipriflavone


Effect: Possible Increased Risk of Toxicity


Like cayenne, the supplement ipriflavone may increase levels of theophylline in the body, possibly increasing the risk of toxicity.




Bibliography


Bartel, P. R., et al. “Vitamin B6 Supplementation and Theophylline-Related Effects in Humans.” American Journal of Clinical Nutrition 60 (1994): 93-99.



Jobst, K. A., et al. “Safety of St. John’s Wort (Hypericum perforatum).” The Lancet 355 (2000): 575.



Nebel, A., R. K. Baker, and D. J. Kroll. “Potential Metabolic Interaction Between Theophylline and St. John’s Wort.” Annals of Pharmacotherapy 33, no. 4 (1999): 502.



Shimizu, T., et al. “Theophylline Attenuates Circulating Vitamin B6 Levels in Children with Asthma.” Pharmacology 49 (1994): 392-397.

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