My electronic medical record device is indicating that I should not prescribe doxycycline to a person with a history of allergy to zithromax (possibly will react to doxycycline). I can't find any additional information on this topic that seems credible. These drugs are in different classes. Am I to be concerned about this as a true possible risk of allergic reaction?


Thank you for your inquiry.

I am in agreement with you. I am not aware of any allergenic cross-reactivity between these two drugs and could find no evidence for such on a literature search. I cannot explain why this warning is in your medical records and suggest you contact the supplier of your system to obtain any references validating the warning or otherwise elucidate its source. If they do have data supporting the statement we would greatly appreciate you notifying us so we could share it with our readers.

Thank you again for your inquiry.

Phil Lieberman, M.D.

We received this additional information from the inquiring physician:

The name of my EMA is “modernizing medicine”

The message that pops up is the following:
Interaction Message: The use of doxycycline hyclate 100 mg capsule may result in an allergic reaction based on a reported history of allergy to Zithromax. This information is based on a survey of 9.7% of the active packaged products for this drug.

Ingredient Interaction Type:
Inactive ingredient match

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