Minerals

Take at a Different Time of Day

Numerous minerals, including aluminum (found in many antacids), bismuth (in Pepto-Bismol), calcium , iron , magnesium , and zinc , interfere with the absorption of medications in the tetracycline family (and vice versa). 1–4

The reason is the minerals and the drugs attach to each other and form insoluble chemicals that simply pass out of the digestive tract. The best solution is to avoid taking supplements that contain these minerals within the 2 hours before or after your dose of tetracycline medication.

Dong Quai , St. John's Wort

Possible Harmful Interaction

Tetracycline antibiotics have been reported to cause increased sensitivity to the sun, amplifying the risk of sunburn or skin rash. Because St. John's wort and dong quai may also cause this problem, taking these herbal supplements during tetracycline treatment might add to this risk.

It may be a good idea to wear a sunscreen or protective clothing during sun exposure if you take one of these herbs with a tetracycline antibiotic.

Citrate

Possible Harmful Interaction

Potassium citrate, sodium citrate, and potassium-magnesium citrate are sometimes used to prevent kidney stones . These supplements reduce urinary acidity, and can therefore lead to decreased blood levels and effectiveness of tetracycline antibiotics. 5