Antibiotics 101: Understanding Their Role and Proper Use

Antibiotics are a group of medications prescribed by your doctor that treat mild to severe bacterial infections. But antibiotics can’t treat every illness. For example, viral infections, like the flu or common cold, can’t be treated with antibiotics. These types of illnesses require different treatment.

Our bodies have a microbiome, which is a community of microorganisms, bacteria, viruses and other microbes that live in and on the human body. Although it may not seem like it, many types of bacteria are good for our health. But some can harm our bodies and multiply in our systems, causing bacterial infections. The role of antibiotics is to eliminate these harmful bacteria and prevent them from multiplying.

After taking antibiotics, you can expect to start feeling better from mild bacterial infections within a few days. For more severe cases, it may take longer to feel relief. Antibiotics can stay in the body from a few hours to several days after you stop taking them. The type of antibiotic your doctor gives you, its dosage and other biological factors will determine how long it remains in your system.

There are three forms of antibiotics: oral, topical and injections. Oral antibiotics are taken by mouth in tablets, capsules or liquid. Some forms of bacterial infections affect the skin. In those cases, topical antibiotics work best. Typically, these are a type of cream that you rub onto the affected area. Injections are used for more severe infections and must be done by a doctor. These are given as a shot or an IV.

With any type of medication, there’s a risk of potential side effects. When it comes to antibiotics, common side effects include:

• Diarrhea
• Dizziness
• Nausea and vomiting
• Rash
• Yeast infections

More serious side effects include Clostridioides difficile (C. diff) infection and anaphylaxis. C. diff is a highly contagious bacterium that causes diarrhea and colitis. It typically affects people who have recently taken antibiotics. Common anaphylaxis symptoms include coughing, wheezing, a closed throat and itchy skin.

What types of illnesses do antibiotics treat?

Antibiotics treat many bacterial infections, including those on the skin and soft tissues, in the throat and respiratory, urinary and reproductive systems. Antibiotics can treat:

• Bacterial pneumonia
• Bacterial vaginosis (BV)
• Cellulitis
• Gas gangrene
• Impetigo
• Infections from animal and human bites
• Lyme disease
• Pink eye
• Sepsis from a bacterial infection
• Sexually transmitted infections (STIs)
• Staph infection
• Strep throat
• Urinary tract infections (UTIs)
• Whooping cough

There are several classes of antibiotics determined by their chemical structure. Some are natural and others are synthetic. Within each class, there are different variations with unique structures. For example, penicillin is a class of antibiotics, and within that class are amoxicillin and ampicillin. Each variation is uniquely designed to treat specific bacterial infections. See the chart below for a few examples.

Just like we wear certain clothing to accommodate the weather, the same is true when it comes to antibiotics. Depending on your bacterial infection, your doctor will choose a specific antibiotic with the right mixture to address your needs properly.

Antibiotics are amazing at treating bacterial infections, but mild cases can heal on their own over time. Whenever possible, you should let your body defeat the illness without taking antibiotics. If you consistently take them for mild bacterial infections, it could lead to antibiotic resistance, which is when the bacteria in your body can resist the effects of antibiotics. Be sure only to take antibiotics if prescribed by your doctor.

While some antibiotics are safe to take when pregnant, there are certain ones that you shouldn’t take if pregnant or breastfeeding. Talk to your primary care provider about what antibiotics are safe for you and your baby. It’s also best practice not to drink alcoholic beverages when taking antibiotics. Some can negatively interact with alcohol and lead to potential health problems.

Yes, antibiotics expire. Over time, they lose their potency, their effects are diminished and some even become toxic.

If you miss a dose of your antibiotics, it doesn’t necessarily mean they’ll stop working. But it can negatively impact their effectiveness in treating bacterial infections and lead to antibiotic resistance. If you miss a dose, check the label on your medication bottle. If you’re unsure what to do, talk to your primary care provider before taking more. And remember, never take two doses at once to make up for a missed day.