I was recently prescribed doxycycline for a chlamydia infection. I didn’t realise that dairy negatively effected absorption of this drug and I have been having the morning does with approximately 200 milliliters of milk in a my morning coffee. My question is could this result in treatment failure?

Many thanks

Only large amounts of dairy products are a problem with doxycycline because they can interfere with absorption of the drug into the bloodstream. It should not be taken at the same time as large servings of milk, ice cream, and so on. However, when I or my clinic treat patients with doxy, we don't say anything about avoiding dairy products. That said, 200 ml is a fairly sizable amount of milk. Probably it has not interfered with effectiveness of your treatment, but to be extra safe it would be reasonable to the doxycycline 30 minutes before or after your morning coffee. Probably this makes no difference, however -- since 200 mg is double the usual dose, so probably plenty of it is being absorbed to be effective against your chlamydial infection. 

The usual doxycycline regimen for chlamydia is 100 mg twice daily. Are you taking 200 mg once or twice daily?

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

My doxycycline dose question was a mistake. On first quick reading, I thought the reference to 200 ml milk was for 200 mg doxy. I recognized then forgot to correct myself before posting my reply. Sorry for any confusion or uncertainty!