4 foods to avoid while taking nitrofurantoin

Nitrofurantoin is an antibiotic used to treat urinary tract infections (UTIs). This generic medication is also sold under the brand names Macrodantin and Macrobid. If you’ve recently been prescribed a course of this antibiotic, you might be wondering what foods to avoid while taking nitrofurantoin. The good news is that there are no known foods that react with or reduce the absorption of nitrofurantoin. However, you may still want to avoid bladder-irritating foods until your UTI clears up, such as acidic and spicy foods.

How nitrofurantoin works

“Nitrofurantoin is an antibiotic used to prevent recurring urinary tract infections or short-term treatment of certain urinary tract infections,” says Christina Bookwalter, Pharm.D., BCPS, BCACP, a clinical pharmacist practitioner in Minneapolis. Nitrofurantoin is often prescribed for bacterial infections in the urinary tract because it concentrates in the bladder and urethra. By acting locally, it kills infection-causing bacteria in the urinary tract without significantly interfering with the bowel microbiome. However, this drug can pass into a nursing woman’s milk supply, so other UTI antibiotic treatments may be preferred for breastfeeding mothers. The risks and benefits of nitrofurantoin use while breastfeeding should be discussed with your healthcare provider.

According to Bookwalter, nitrofurantoin works quickly. Bladder infection symptoms often improve within 48 hours, though it is important to finish the full course of prescribed treatment to prevent recurrence.

4 foods to avoid with nitrofurantoin

Food does not impact the effectiveness of nitrofurantoin. However, says Inna Melamed, Pharm.D., a functional medicine practitioner and author of Digestive Reset, certain foods should be avoided when you have a UTI to avoid worsening symptoms. The list below outlines four foods that should be avoided.

1. Acidic foods and drinks

Acidic foods such as tomatoes and citrus fruits can irritate your bladder, and the same goes for acidic drinks such as coffee and orange juice.

Think about it: When a part of your body is infected, you want to avoid irritating the area. An irritated bladder could exacerbate UTI symptoms such as painful urination or a frequent urge to urinate.

2. Spicy foods

Consider taking a break from spicy foods while taking nitrofurantoin. The reason is that spicy food can cause or aggravate indigestion and stomach pain—common side effects of nitrofurantoin.

3. Alcohol

Alcohol, like spicy foods, can exacerbate gastrointestinal (GI) distress. Drinking alcohol can also cause dizziness, which is another common side effect of nitrofurantoin. It’s best practice to avoid mixing alcohol with antibiotics since combining them may increase your risk of side effects.

4. Caffeine

Though there’s no direct interaction between nitrofurantoin and caffeine, consuming too much caffeine can make UTI symptoms worse. That’s because caffeine is linked to bladder overactivity. If you have a UTI, reducing or eliminating caffeine temporarily may help soothe urinary urgency.

Bottom line: It’s important to remember that you are avoiding these foods because they may worsen UTI symptoms or nitrofurantoin side effects, not because they diminish the effectiveness of nitrofurantoin. There are no major drug-food interactions with nitrofurantoin. If your UTI symptoms have subsided, you can eat and drink what you want—tomatoes, cheese, eggs, bananas, jalapenos, and coffee.

Herbs and supplements to avoid with nitrofurantoin

Nitrofurantoin has relatively few interactions with supplements. However, Dr. Melamed stresses that nitrofurantoin should not be taken with antacids that contain magnesium. That’s because drug interactions between nitrofurantoin and magnesium trisilicate can impede your body’s ability to absorb the antibiotic.

In general, it’s a good idea to keep a list of the medications, herbs, vitamins, and supplements you take. Show this list to your healthcare provider and ask if you should avoid or temporarily limit anything while taking nitrofurantoin.

What should you eat while taking nitrofurantoin?

“It is best to take nitrofurantoin with food to ensure your body absorbs the drug. This allows it to work properly to treat the infection,” says Dr. Bookwalter. 

The best things to eat while taking nitrofurantoin are foods that may help relieve your UTI symptoms. Cranberries, along with healthy, antioxidant-rich foods such as blueberries, dark chocolate, broccoli, and spinach, may help relieve UTI symptoms and prevent recurrent UTIs. However, these foods are not a substitute for an antibiotic to treat a UTI. 

It’s also a good idea to eat probiotic-rich foods such as yogurt, sauerkraut, and kimchi when you are on antibiotics. Probiotics can help prevent diarrhea caused by a disrupted intestinal microbiome. While Dr. Melamed recommends probiotics while taking antibiotics, she recommends spacing out your probiotic and antibiotic intake—eating yogurt with breakfast and taking your antibiotic at lunch, for instance.

It is important to stay well hydrated with water when treating a UTI. Fluids help flush out bacteria from your urinary tract. Drink unsweetened cranberry juice, along with plenty of water, between each dose of nitrofurantoin. However, people with certain medical conditions like kidney, liver, or heart disease may have to limit their fluid intake. If you have these conditions, talk to your provider before changing how much you drink. 

Gastrointestinal side effects of nitrofurantoin

It’s not unusual for antibiotics like nitrofurantoin to cause diarrhea. Antibiotic-related diarrhea is typically caused by a disruption in the gut microbiome—the balance of good and bad intestinal bacteria. You may experience more frequent or looser stools while taking nitrofurantoin. The diarrhea should go away after you have finished the prescribed course of treatment.

Other side effects caused by nitrofurantoin include:

• Nausea
• Gas
• Vomiting
• Loss of appetite
• Stomach upset
• Abdominal pain
• Discolored dark yellow or brown urine

Consult a healthcare professional immediately if you develop any of these rare but serious side effects of nitrofurantoin:

• Severe abdominal pain
• Upper abdominal pain with jaundice
• Bloody diarrhea
• Shortness of breath
• Chest pain

Also, seek medical advice if you have any signs of an allergic reaction, such as hives, swelling of the face or throat, burning eyes, or a painful skin rash. If you believe you are allergic to nitrofurantoin, do not take your next dose before consulting a healthcare professional.