Every antibiotic question you have, answered

Antibiotics are medicines used to treat infections caused by bacteria. There are several classes of antibiotics – some only target specific bacteria, while others can be used against a variety of organisms.

This article will explore how antibiotics work, what they are used to treat, and how quickly they can help end an infection.

Learn about the many benefits of antibiotics for fighting infections

What are antibiotics?

Antibiotics are substances that start in nature, usually in the soil as fungi or other forms of bacteria. These substances can bind to the cell walls of harmful bacteria, penetrate the cell to kill the bacteria or prevent them from multiplying.

Penicillin was the first antibiotic to be developed, and it happened by accident.

British scientist Alexander Fleming discovered in the late 1920s that penicillin was grown on the same plate Staphylococcus aureus Bacteria are destroying bacteria. He determined that Penicillium produced a substance that could dissolve the bacteria, and over the next few decades, penicillin was increasingly used to treat a variety of infections.

The development of antibiotics exploded after World War II, and today there are several classes of antibiotics to choose from. Each has its place in the treatment of bacterial infections, some are used to attack multiple types of bacteria, while others have more specialized uses.

How do healthcare providers choose the right antibiotic treatment?

How do antibiotics work?

Antibiotics work by binding to bacterial cells and penetrating their cell walls. Once inside the bacterial cell, these drugs either kill the bacteria or stop it from multiplying and growing. Antibiotics are divided into several categories based on how they enter the cell wall and destroy bacteria. This is called the mechanism of action.

Antibiotics by mechanism of action

Different types of antibiotics fight bacteria in different ways. Below are some examples.

Antibiotics that destroy cell walls:

  • Beta-lactam antibiotics
  • glycopeptide

Antibiotics that change bacterial genetics:

  • Tetracyclines
  • Macrolides
  • Oxazolidinones

Antibiotics that prevent bacteria from multiplying:

  • Quinolones
  • Sulfonamides

Some antibiotics work best against certain types of bacteria. Mainly divided into antibiotics against Gram-positive bacteria with simple cell walls and antibiotics against more complex Gram-negative bacteria.

Your healthcare provider may treat you with broad-spectrum antibiotics that are effective against both gram-positive and gram-negative bacteria, but some infections may require culture tests to identify specific forms of the bacteria. By determining the exact type of bacteria that is causing your illness, your healthcare provider can prescribe the most effective form of antibiotics for that particular bacteria.

How long does it take them to work?

How long antibiotics take to work depends on the infection being treated and the type of antibiotic you are taking. Some antibiotics are most effective at high concentrations, and these antibiotics may be given as an intravenous infusion. Other types of antibiotics will be more effective over time.

For example, levofloxacin belongs to the fluoroquinolone class of antibiotics, which reaches its peak performance depending on the concentration. It is a stronger antibiotic that starts to work within hours, but can take days to completely cure the infection.

Penicillin, on the other hand, works for a while. Depending on how your disease spreads, it may take days or even weeks to fully work. For example, when used to treat strep throat, penicillin can make you non-infectious to others for about a day, but you may need to continue taking the medicine for a few days to resolve your own infection.

Always take antibiotics according to the full regimen prescribed by your doctor. Stopping your course of antibiotics early may worsen your infection or increase your overall resistance to antibiotics. Even if you start to feel better, some antibiotics will continue to work after you stop taking them, The speed at which they work varies from person to person.


Antibiotics only work against bacterial infections, and some antibiotics only work against certain types of bacteria.

Gram-positive bacteria have a simple cell wall, but Gram-negative bacteria have an extra layer around them that is more difficult for antibiotics to penetrate. Antibiotics are usually prescribed as broad-spectrum antibiotics—meaning they treat both types of bacteria, or are prescribed specifically for the type of bacteria that causes your infection.

Common antibiotics are listed below, depending on the type of bacteria they fight, as well as some common infections they may be used to treat. For example, penicillin and vancomycin should only be used to treat infections caused by Gram-positive bacteria. This includes throat infections, C.diff Infections and neurosyphilis – infections of the brain and spinal cord.

Other antibiotics such as amoxicillin, ampicillin, cephalosporins, and fluoroquinolones treat a variety of gram-positive and gram-negative infections, including sepsis and urinary tract infections.

The only time a doctor should prescribe antibiotics for pneumonia

Antibiotics are not a panacea

Antibiotics should only be used for specific bacterial infections. Taking antibiotics only when appropriate can help fight antimicrobial resistance. Antibiotics do not work against viruses, and they cannot be used to treat infections such as the flu or COVID-19.

You should also make sure to always take a full course of antibiotics. Don’t save them in case you get sick later – the antibiotics you take for one infection may not work for another. You also should not share your antibiotics with anyone or use antibiotics that were not prescribed to you.

side effect

Side effects of antibiotics can vary depending on the type of antibiotic you are taking, the prescribed dose, and other health problems you may have. Some other medicines can affect how your antibiotics work and the side effects you have.

alcohol and antibiotics

The use of alcohol with most drugs, including antibiotics, is not recommended because of concerns that the use of alcohol with these drugs will reduce their effects and increase their toxicity. There have been warnings against using alcohol with several specific types of antibiotics, such as doxycycline and cephalosporins, but the science behind these recommendations has recently been questioned.

A 2020 paper reviewed the data behind these recommendations and found that most studies on combined alcohol and antibiotic use are limited, focusing on antibiotic use among alcoholics and heavy drinkers. Few studies have investigated the effects of socializing or limited alcohol consumption while taking antibiotics.

While the paper raises questions about the real dangers of using alcohol with antibiotics, the authors recommend that alcohol should still be avoided while antibiotics are being used until more research is done.

Most side effects of antibiotics stem from the fact that they may not only target the bacteria that caused your infection. Antibiotics can kill “good” bacteria and disrupt your body’s natural balance, especially your gut. Using probiotics while taking antibiotics may help reduce some of these side effects.

Common side effects of antibiotics include:

  • rash
  • nausea
  • diarrhea
  • yeast infection

If you experience shortness of breath, hives, or other symptoms of an allergic reaction, stop taking antibiotics and call your healthcare provider right away.

Common and Serious Antibiotic Side Effects in Children

antibiotic resistance

Antibiotic resistance is a problem that arises from the overuse and misuse of antibiotics. When this happens, it’s not your body that becomes resistant to antibiotics. In contrast, bacterial antibiotics are designed to kill or damage no longer affected by the drug.

You can help avoid antibiotic resistance by taking antibiotics only as directed by your doctor, and only when you really need them. Antibiotics don’t work on everything, and they don’t work on viruses. The Centers for Disease Control and Prevention estimates that about one-third of antibiotics prescribed in the U.S. each year are unnecessary and used for conditions that should not be treated with antibiotics.

U.S. Updates Antibiotic Resistance Program: Here’s the Latest News

When to see a healthcare professional

You should only take antibiotics as directed by a healthcare professional. If your symptoms worsen or do not resolve after your entire course of antibiotics, discuss other treatment options with your healthcare provider.

You should also alert your healthcare provider to any side effects you experience while taking antibiotics, even if they are mild. If you have symptoms of an allergic reaction while taking an antibiotic, go to the emergency room or seek medical attention right away.

Symptoms of Anaphylactic Shock

VigorTip words

Antibiotics are very useful tools in medicine, helping to treat a variety of infections that were once deadly. Antibiotics work quickly, but how quickly depends on the type you are taking and the condition you are being treated for. Always take antibiotics for the entire time prescribed by your doctor and exactly as prescribed. Stopping antibiotics too early or taking them incorrectly can lead to antibiotic resistance and make you more susceptible to dangerous infections.

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Frequently Asked Questions

  • Can I take antibiotics?

    Taking antibiotics while drinking alcohol is not recommended, especially certain varieties. Talk to your pharmacist doctor about the specific antibiotic you are prescribing and how it might interact with alcohol. It’s also a good idea to check the effects of alcohol on any other drugs you may be taking.

    understand more:

    Zorvolex (diclofenac) and alcohol

  • What happens when you drink antibiotics?

    While the science behind the advice to avoid alcohol while taking antibiotics has been debated, it is widely believed that alcohol reduces the effectiveness of antibiotics and increases toxicity levels. You may experience increased nausea or vomiting when you combine antibiotics with alcohol.

    understand more:

    Dangers of mixing alcohol and drugs

  • How long does it take for a UTI to go away without antibiotics?

    Urinary tract infections may resolve on their own without antibiotics, but antibiotics can help shorten the duration of infection and help prevent complications. UTIs can be treated with antibiotics within a few days, but if not, it can last longer. To make matters worse, untreated UTIs can lead to more serious illnesses such as kidney infections and even uremia.

    understand more:

    symptoms of urinary tract infection

  • How long do antibiotics stay in your system?

    How long antibiotics stay in your system depends on the type of antibiotic you are taking. Some last only a few hours after your last dose, while others can stay in your system for weeks. The types of antibiotics that last the longest in your body include some types of penicillin and hydroxychloroquine.

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