Which of the following conditions occurs when normal flora is disturbed during antibiotic therapy?

Antibiotics can act as a powerful defensive line against bacterial infections. They're remarkably effective at killing the harmful bacteria that cause disease. Unfortunately, they also come with a cost.

"Antibiotics play a critical role in fighting bacterial infections," explains Jasmine Omar, M.D., an internal medicine specialist at Henry Ford Health. "But taking these medications can also lead to adverse reactions including nausea, drug allergies, antibiotic-associated diarrhea and yeast infections."

Frequently Asked Questions About Antibiotics

Antibiotics are still the most frequently prescribed medication in the United States, but not all illnesses require antibiotics. In fact, two of the most common ailments — cold and flu — do not respond to antibiotics.

If you have an illness that requires antibiotics, something like strep throat, bacterial pneumonia or urinary tract infections, it's important to understand how these drugs affect your body — both while you are taking them and over the long haul.

Since there's so much confusion and controversy surrounding antibiotic use, we asked Dr. Omar to answer patients' frequently asked questions.

Q: How do antibiotics work in the body?

A: Most antibiotics work by killing bacteria or preventing it from growing. Unfortunately, most antibiotics can't distinguish between good and bad bacteria. That means they can wreak havoc on your gut’s healthy bacteria. In fact, many people suffer lasting changes to their gut flora as a result of taking antibiotics.

Q: Do I need to worry about food or drug interactions while I'm taking antibiotics?

A: Certain antibiotics, such as metronidazole, can interact with alcohol. If you're taking these medications, it's important to avoid alcohol during treatment. Others, such as rifampin, can interfere with the effectiveness of oral contraceptives (birth control pills). To be safe, we sometimes recommend that people use a backup birth control, like wearing a condom, while they're taking certain antibiotics. Be sure to read and follow the directions and any warnings provided by your pharmacy with your specific prescription.

Q: What kinds of side effects are common while taking antibiotics?

A: Taking antibiotics can dramatically change the amount and type of bacteria in the gut. These changes in the gut microflora can lead antibiotic-associated diarrhea, nausea, vomiting and other gastrointestinal side effects. That's one reason why doctors recommend taking antibiotics with food. Taking antibiotics can also lead to vaginal yeast infections. Like the gut, the vagina is home to good bacteria, which can be negatively affected during antibiotic treatment.

Q: Are some people more sensitive to the side effects of antibiotics than others?

A: Yes. If you notice significant side effects, talk to your doctor. He or she may be able to offer advice on how to reduce them, or prescribe a different antibiotic with fewer side effects — or prescribe medication to counter the negative side effects. 

Q: Which antibiotics trigger the most side effects?

A: There are many different types of antibiotics. Some are broad-spectrum, meaning they target a wide range of bacteria. Others target specific species of bacteria. Your doctor will determine which antibiotic is best for your infection based on the type of illness you have and your health history.

Q: Why is protecting the healthy gut bacteria so important?

A: Your intestines house more than 100 trillion types of bacteria. They break down your food, help you maintain a strong immune system and maintain the natural order of your bodily functions. Some doctors believe that taking probiotic supplements during antibiotic treatment can reduce the negative effects on your gut flora and potentially boost your immune response in the process. But the evidence to support this idea is slim. Talk to your doctor before taking probiotic supplements since they may be harmful for people who have immune system disorders.

Q: What does the latest research on probiotics suggest?

A: There's some evidence to suggest that taking certain strains of probiotics, such as Lactobacilli and Saccharomyces, can protect against antibiotic-associated diarrhea. Unfortunately, this research doesn't address the potential harms of taking probiotics. A recent study found that taking probiotics could delay the normal recovery of the gut's natural microbiota. The bottom line: We still don't know which types of bacteria are beneficial, or whether they could be harmful.

Q: Are there particular dosing instructions for probiotics?

A: Not really. Doctors who recommend probiotics typically suggest that people take them a few hours after their antibiotic. Otherwise, the two medications can cancel each other out. Some doctors even suggest waiting to start probiotics until a few days after you've completed your course of antibiotics.

Q: How can I better support my gut and immune system while taking antibiotics?

A: Without solid evidence to support the use of probiotics alongside antibiotic therapy, your best bet is to load up on foods that contain healthy bacteria — things like yogurt, kefir, kimchi and sauerkraut. You can also feed the bacteria in your gut by eating fiber-rich foods, such as nuts, seeds, beans, lentils, peas and berries.

Antibiotic Safety

Taking antibiotics you don’t need can lead to antibiotic resistance, meaning illnesses that were once easily treated with antibiotics no longer respond to the medications.

"We're really trying to make sure we're prescribing the right medication for the right reasons," Dr. Omar says. "When antibiotics are not indicated, they're ineffective and they can also produce negative and sometimes long-term side effects."

Unfortunately taking probiotics isn't the solution. While probiotics are "generally recognized as safe," they are not appropriate for everyone. In fact, taking probiotics can be harmful for people who are immune compromised, and who have conditions like small bowel intestinal overgrowth.

Not sure how to best weather your illness and antibiotic treatment? Have a conversation with your doctor to guide your treatment decisions and help minimize the side effects of medication.

To find a doctor at Henry Ford, visit henryford.com or call 1-800-HENRYFORD (436-7936).

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Dr. Jasmine Omar is an internal medicine doctor who sees patients at Henry Ford Hospital in Detroit.

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