Health & Wellness

11 Foods to Avoid when Taking Sulfamethoxazole / Trimethoprim

Looking for foods to avoid when taking sulfamethoxazole-trimethoprim? It’s a widely prescribed medication for treating bacterial infections such as urinary tract infections, ear infections, and respiratory tract infections.

While it can be very effective in helping to alleviate various health issues, certain foods should be avoided when taking this medication. This is because these foods can affect the absorption and effectiveness of Sulfamethoxazole-Trimethoprim and lead to unwanted side effects.

So if you’re taking Sulfamethoxazole- Trimethoprim or know someone who is, ensure they know these dietary restrictions to get the best possible results from their treatment!

This article will discuss the foods you should avoid when taking Sulfamethoxazole-Trimethoprim. Understanding these dietary restrictions can help you make informed choices and achieve the best possible results from your treatment.

In This Article

  1. Foods to Avoid when taking Sulfamethoxazole / Trimethoprim

Foods to Avoid when taking Sulfamethoxazole / Trimethoprim

Here we have listed trimethoprim-sulfamethoxazole and food interactions and what to avoid when taking sulfamethoxazole:

Foods to Avoid when taking Sulfamethoxazole

1. High-potassium foods

Some high-potassium foods, such as bananas, oranges, and potatoes, may increase the potassium levels in the body when taken with sulfamethoxazole-trimethoprim.

That said, following your doctor’s advice is important if they tell you to limit potassium intake due to any medical condition. So make sure you check with them before making changes to your diet.

2. Spicy foods

It’s not necessarily a complete contraindication; consuming spicy foods can potentially irritate the gastrointestinal system while taking this sulfamethoxazole, as it can already cause nausea, vomiting, or stomach upset in some individuals. Eating too much spice may worsen these side effects or cause additional discomfort.

3. Caffeine

What can you not take with sulfamethoxazole is Caffeine. It is a stimulant that can increase heart rate, cause nervousness or disrupt sleep patterns. Similarly, sulfamethoxazole/trimethoprim may also lead to nervousness or sleep disturbances. However, it’s important to remember that caffeine does not directly interact with medication like Sulfamethoxazole-Trimethoprim.

4. Artificial Sweeteners

It’s important to know the potential interactions between certain foods and medications. For example, if you’re taking sulfamethoxazole/trimethoprim (a sulfonamide antibiotic), it is recommended that you avoid artificial sweeteners containing aspartame due to possible interactions.

Additionally, some people may have an allergic reaction to this type of medication which can manifest as a reaction toward the sulfa-containing compounds in the antibiotic. Just wanted to make sure everyone was aware!

5. Soy Products

If you’re taking sulfamethoxazole/trimethoprim, it’s important to be mindful of the soy products in your diet. Soy contains compounds called phytates which can bind with minerals and reduce their absorption in the digestive tract. This could affect how well this antibiotic works against bacterial infections.

6. Alcohol

Just wanted to remind you that if your doctor has prescribed sulfamethoxazole/trimethoprim for an infection, it’s important to avoid alcohol while taking the medication. Doing so can help ensure the treatment is effective and reduce potential side effects.

7. Dairy products

Did you know that dairy products can interfere with the absorption of sulfamethoxazole/trimethoprim? Calcium in these foods binds to the medication and forms insoluble complexes not absorbed into our bloodstream.

This means that reduced levels of medication could affect its effectiveness. Something to keep in mind if you’re taking this type of medicine!

8. Grapefruit and Grapefruit juice

Did you know that grapefruit and grapefruit juice can affect certain medications? It’s true! The furanocoumarin compounds in these foods can interfere with the metabolism of drugs like sulfamethoxazole/trimethoprim.

These compounds block an enzyme in your liver and intestines called cytochrome P450 (CYP3A4), responsible for metabolizing many drugs.

9. Certain Herbal Supplements

Various herbal supplements such as ginkgo biloba, garlic, and saw palmetto can interact with sulfamethoxazole/trimethoprim and affect its effectiveness.

If you are taking any of these herbal supplements, please consult your healthcare provider for the best advice on how to proceed.

10. Processed foods

The absorption of medication, such as sulfamethoxazole/trimethoprim, may be affected by the chemicals, preservatives, and artificial components frequently included in processed foods. These substances may impact how the body absorbs and processes the medicine, decreasing effectiveness.

11. St. John’s Wort

The herbal supplement St. John’s Wort is well known for interacting with several medications, including sulfamethoxazole/trimethoprim.

St. John’s Wort is known to induce certain liver enzymes responsible for metabolizing drugs in the body. St. John’s Wort may lessen the efficiency of sulfamethoxazole/trimethoprim by boosting the enzyme activity that breaks down the medicine.

Frequently Asked Questions & Answers:

Q. Can you take sulfamethoxazole/trimethoprim with food?

Ans- Yes, sulfamethoxazole/trimethoprim can generally be taken with food. Taking the medication with a meal or snack is known to help reduce any potential stomach upset or gastrointestinal discomfort.

Q. Do you take trimethoprim before or after food?

Ans- Some medications are better absorbed with food, while others may be absorbed more effectively when taken on an empty stomach. Trimethoprim is generally well-tolerated and can be taken with or without food.

Q. Can you drink alcohol with trimethoprim/Sulfamethoxazole?

Ans- No, it is generally not recommended to drink alcohol while taking trimethoprim. Combining alcohol with trimethoprim can increase the risk of certain side effects and may interfere with the effectiveness of the medication.

Both alcohol and trimethoprim can impact liver function, and combining the two can put additional strain on the liver, potentially leading to liver damage or other complications.


In conclusion, it’s important to be mindful of the foods you eat while taking Sulfamethoxazole-Trimethoprim. High potassium levels in bananas, oranges, and leafy greens can increase your risk for hyperkalemia.

Alcohol should also be avoided as it could have adverse effects on the liver and interfere with how this medication is metabolized. So let’s stay safe by eating healthy and avoiding drinks that contain alcohol!

Be sure to read:


  1. Trimethoprim Sulfamethoxazole
  2. Considerations when prescribing trimethoprim-sulfamethoxazole
  3. interaction of vitamin K antagonists and trimethoprim-sulfamethoxazole

Dr Maria

MD. Board Certified physician. Fellowship In Family Medicine UK. 8 years of medical experience in Lifestyle-related health disorders. Graduated from AIIMS – All India Institute Of Medical Science, INDIA

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