Patients should consult their physician before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications while taking antibiotics. Of particular concern to individuals taking antibiotics are:

• Other antibiotics. Physicians may prescribe several different types of antibiotics to be taken simultaneously to treat certain types of infections, but the use of multiple antibiotics can also increase the risk of side effects.
  
  
• Anticoagulants. Medications that prevent the formation of blood clots. Certain types of antibiotics may increase the effect of anticoagulants.
  
  
• Antacids. Medications that balance gas and acids in the stomach. The use of antacids with certain antibiotics (e.g., fluoroquinolones, tetracyclines) may decrease the effectiveness of both medications.
  
  
• Insulin. The antibiotic tetracycline has been shown to interfere with insulin production in the body and increase a person’s insulin resistance.
  
  
• Nonsteroidal anti-inflammatory drugs (NSAIDs). Medications that reduce pain and inflammation by inhibiting the production of certain chemicals in the body. Certain antibiotics may increase the incidence or severity of side effects due to NSAIDs.
  
  
• Antiviral medications. Certain antibiotics may decrease the effectiveness of these virus-fighting medications.
  
  
• Diarrhea medications. These may increase the effects of certain types of antibiotics.
  
  
• Calcium supplements. These may decrease the effectiveness of certain types of antibiotics.
  
  
• Oral contraceptives. Medications that control a woman’s menstrual cycle and prevent pregnancy. Antibiotics can lessen the effectiveness of birth control pills, and women may require a back-up birth control method.
  
  
• Bronchodilators. Medications that widen airway passages in the lungs and are often used in the treatment of asthma. Certain types of antibiotics may increase the concentration levels of some bronchodilators, although the two medications are routinely used together.
  
  
• Gout medications. Gout is a painful joint inflammation. Gout medications may increase the effects of certain types of antibiotics.
  
  
• Alcohol. Certain antibiotics may increase the risk of liver damage from alcohol abuse.
  
  
• Caffeine. Certain antibiotics may increase the risk of toxicity (or overdose) from caffeine.