What Foods Need to Be Avoided While Taking Bactrim?

Bactrim belongs to the class of drugs called sulfa drugs. Bactrim contains sulfamethoxazole, a form of sulfa and trimethoprim, a man-made antibiotic that enhances the effect of sulfamethoxazole. Sulfites in foods, despite the name similarity, have no connection to sulfa drugs. Manufacturers add sulfites to wine, beer and some medications as a preservative. Bactrim can cause reactions when taken with products containing alcohol. If you have kidney disease, Bactrim could also raise potassium levels so you may need to restrict foods high in potassium.

Avoiding Alcohol

When you're taking Bactrim, avoid all foods or beverages that contain alcohol. Bactrim may interfere with acetaldehyde dehydrogenase, a substance that helps break down alcohol so your body can metabolize it. This reaction is similar to the reaction caused by the drug disulfiram, sold as Antabuse, a drug to deter alcoholics from drinking.

Cooking with Alcohol


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Foods cooked with alcohol may retain a surprising amount of alcohol. When you add alcohol to a sauce and then removed it from the heat, the sauce retains 85 percent of the alcohol content. Flamed foods retain 75 percent of their original alcohol content, while foods baked for 30 minutes still retain 35 percent of original alcohol, registered dietitian Joanne Larsen, M.S. explains on the website, Ask the Dietitian.

Sulfites in Alcohol

Sulfites, once used to keep fruits and vegetables from turning brown, were banned from many foods by the United States Food and Drug Administration in 1986 due their potential for allergic reactions. Although beer and wine still contain sulfites, it's the alcohol content, not the sulfites, that affects you when you're taking sulfa drugs.

Potassium-Rich Foods


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In people with impaired kidney function, Bactrim might increase potassium levels. If you have kidney problems, ask your doctor if you should avoid salt substitutes, which contain large amounts of potassium as well as food high in potassium, such as:

  • bananas
  • chocolate
  • milk
  • cooked spinach
  • potatoes
  • pumpkin