Calcium in connection with antibiotics

Question

Hello,

some antibiotics (oral taking) should not be taken in connection with milk since their effect is reduced/altered by the calcium contained in the milk. This is what the package insert of the antibiotic usually says. My question now: the calcium content of milk is about 100-130 mg/l, our mineral water contains about 555mg/l. Is it therefore not advisable to switch to a mineral water with less Caclium content or does this have no influence on the effect of the antibiotics?

Answer

Hello,

as your question describes correctly, there are certain antibiotics, e.g. tetracylinces (e.g. doxycycline), gyrase inhibitors (e.g. ciprofloxacin) and also macrolides (e.g. Zithromax®/azythromycin) that interact with, among others, calcium or other metal ions such as magnesium, iron, or zinc and thus significantly impair resorption in the intestinal tract. This can sometimes lead to a considerable decrease in concentration of the agent.

These metal ions can be taken as:

DRUGS – for instance in the form of mineral preparations (e.g. calcium compounds against osteoporosis or allergies, magnesium compounds against muscle cramps, minerals for athletes, multivitamin compounds with minerals, iron compounds) or as mineral antacids (e.g. Rennie® or Talcid®, which buffer excess gastric acid in case of heartburn); or as

CALCIUM-CONTAINING FOOD including milk products (milk, curd, yogurt, cheese), mineral water and also calcium-enriched fruit juices.

The individual package inserts do not consistently point to the different sources of metal ions. I nevertheless recommend to also pay attention to other calcium sources (mineral preparations, mineral antacids and other calcium-containing food) if the package insert recommends a certain time interval to eating milk products. It is the calcium content that is significant for this interaction, and like you say correctly, your mineral water has a much higher calcium concentration than milk.

Ciprofloxacin and doxycyclin, for instance, come with the following directions:

- The antibiotic should be taken with a glass of tap water.

- The antibiotic should be taken no earlier than four hours after consumption of calcium-containing food, and respectively, calcium-containing food should not be consumed earlier than two hours after taking the antibiotic.

If you follow these time intervals with your mineral water as well when taking these antibiotics and, for instance, resort to tap water in the meantime, it is not a problem to drink your usual mineral water for the rest of the day. The interaction with the metal ions only concerns the resorption of the antibiotic in the gastrointestinal tract, which is complete after this time frame.

Especially in hot weather, it is important for people with CF to take enough minerals in order to make up for the increased sweating, so that switching completely to water with reduced mineral content does not seem sensible.

I hope this information helps answer your question.

Kind regards
Eva-Maria Miserre

14.09.2010