Functioning of Antibiotics, how long they take to be effective and more

Antibiotics are drugs that fight against bacterial infections by either killing the bacteria or slowing down their growth. They are sometimes called antibacterials. Antibiotics are not the answer for every infection. There are two types of germs that cause infections and antibiotics are perfect only for treating bacterial infections.

How do Antibiotics work?

Bacteria are organisms that thrive on skin, in digestive system, in mouth and throats. There are one hundred thousand billion bacteria living in our body. Although most of these bacteria are harmless and actually help our body positively by breaking down the nutrients in our diet, some are harmful and can cause serious infections. They are responsible for many diseases like strep throat, ear infections, sinus infections and urinary tract infections.

On the other hand, viruses are smaller than bacteria. Viruses can cause mild as well as severe diseases. They are responsible for causing cold, flu, sore throats and coughs. They sometimes also cause measles, smallpox, hepatitis, mumps, and AIDS. Although antibacterials are powerful, they are cannot kill viruses and so they do not work against viral infections. When given for viral infections, they can not only cause side effects, but they can also cause antibiotic resistance. Antivirals are drugs that are actually used to treat viral infections.

You should take antibacterials as recommended, and then you will start feeling better in no time. But it all depends on the type of drug and duration of its usage.

Any slight alteration can make these medicines ineffective. Therefore, it becomes important to consult your doctor before taking any antibiotic treatment.

Antibiotics fight against these bacteria by –

  • Attacking the wall around bacteria
  • Stopping their growth
  • Obstructing the bacteria’s protein production

How much time does it take for antibiotics to work?

Antibiotics start functioning soon after you begin taking them. However, it takes two to three days for you to feel better. Most antibiotics are usually taken for one or two weeks. In some cases, short duration of treatment works too; it depends on your infection. Your doctor might prescribe an antibiotic regimen according to your infection.

Antibiotic fosfomycin is given to patients as a single dose as it works immediately, whereas another antibiotic tetracycline takes several weeks to make the patient feel better. If the medicine starts working and you feel better within few hours, then you should be better in a couple of days. But it is recommended to take the entire course for recovering completely from the infection. It can also help you prevent any reoccurrence or resistance to antibiotics. Don’t stop taking antibiotics in the middle of your treatment without consulting your doctor.

Resistance to antibiotics

Antibiotic resistance happens when the growth of bacteria cannot be controlled by certain medications. Bacteria generally mutate naturally and spontaneously. However, certain times it happens that you put pressure on them to mutate more and develop resistance to these drugs. One of the major factors in bacteria developing resistance against antibiotics is the inappropriate use of antibiotics or overuse of antibiotics. Many times antibiotics are used when they are not really needed i.e. using antibiotics even if you have a viral infection or treating someone with the wrong type of antibiotic that is not suited for the bacterial infection that the person is suffering from.

In other words when you take antibiotics, it first eliminates the sensitive bacteria. The bacteria that will survive during the antibiotic treatment are often those that become resistant to the medicine. The bacteria evolve and become stronger. So, if in future you suffer from a bacterial infection, your body would not respond effectively to the same antibiotic medication. It becomes impossible to control any antibiotic resistance using these drugs.

In some cases, it means that there are no effective treatments for certain health conditions. According to National Institutes of Health, misuse of antibiotics is resulting in widespread drug resistance.

Every year in the United States around 2 million people are becoming infected with bacteria that are resistant to antibiotics and at least 23,000 people are dying annually because of these infections; many more people die from complications resulting from antibiotic-resistant infections, says National Institutes of Health.

There are some infections that become resistant to antibiotic treatment such as –

  • Carbapenem-resistant Enterobacteriaceae (CRE) – this group of bacteria is resistant to antibiotics. Infections due to CRE occur in patients using mechanical ventilators. It is also common in admitted patients.
  • Clostridium difficile (C. diff) – this bacteria is resistant to many antibiotics. It affects large and small intestines. Most of the times this happens when someone is treated with these drugs for a different bacterial infection.
  • Methicillin-resistant Staphylococcus aureus (MRSA) – MRSA infections are caused on skin. It mostly affects people having weak immune system.
  • Vancomycin-resistant enterococcus (VRE) – these bacteria infect surgical wounds, urinary tract and bloodstream. It occurs in people who are admitted in hospitals. The infections caused due to enterococci may be treated with the antibiotic named vancomycin. However, VRE is often resistant to this treatment.

According to the Centers for Disease Control and Prevention (CDC), 30 percent of antibiotics use is considered unnecessary. In most of the cases, antibiotics are prescribed when they are not needed.

You should always use antibiotics very carefully. Here are some things that you need to keep in mind to use these drugs appropriately so you can get effective treatment when you are sick, protect yourself from any unnecessary antibiotic use and to combat any antibiotic resistance.

  • Use antibiotics only for bacterial infections. These drugs treat infections that are only caused by bacteria such as whooping cough, strep throat, and urinary tract infections.
  • Do not use antibiotics for infections caused by viruses such as cold, runny nose, sore throats, flu and bronchitis.
  • Antibiotics are also not needed for some bacterial infections like sinus infections and certain ear infections.
  • They are also not effective for infections caused due to fungi such as ringworm, fungal toenail infections, athlete’s foot, and yeast infections.

To address the growing antibiotic resistance, the National Institute of Allergy and Infectious Diseases (NIAID) is working towards developing faster ways to detect antibiotic resistance and find new treatments that are effective against these bacteria that are drug-resistant.

Is Antibiotics good for long-term use?

It is very important to take antibiotics as prescribed. You should not take them for longer period of time as it will raise your chances of suffering from its unwanted side effects. Earlier doctors used to prescribe antibiotics for long-term use as they thought that patients needed to take these medications for long-term to kill the bacteria. However, studies have shown that using antibiotics for long-term is actually harmful. When you take antibiotics for long-term, it will eliminate the harmful bacteria first, then it will attack the beneficial bacteria. This will interfere with the normal functioning of your body and it will cause severe health issues.

How to take antibiotics?

If you undertake or overtake antibiotics, you will not get completely treated. It is essential to use these drugs correctly. You should always take antibiotics as prescribed by your physician. Do not overdose or skip doses. Do not take antibiotics prescribed for someone else. Also, avoid using left over antibiotics from a previous treatment. Taking antibiotics for longer or shorter period can cause serious infections. Antibiotics are only suitable for bacterial infections so do not take it for viral infections. Since there are many groups of antibiotics, it is important to use the correct one. Using the wrong medicine can result in serious side effects. Thus, in order to avoid any such problem, it is important to consult your doctor before taking any antibiotic. The doctor will conduct tests to determine the root cause of your infection and he will accordingly suggest appropriate antibiotic and the duration of its use.

What do antibiotics contain?

Penicillin was the first antibiotic to be discovered. It was accidentally found by Alexander Fleming in a petri dish with mold. In early days, some antibiotics were also made by bacteria found in soil.

After penicillin was found, scientists through an inclusive research came to know that it is a particular fungus that produces penicillin. Later, it was discovered that we can even grow this fungus in a laboratory. Thus, following this discovery, antibiotics were produced using fermentation process. Since that time the antibiotics formulation improved significantly. Today, penicillin is produced using chemical reactions, but there are some types of antibiotics that are made by natural methods.

There are many types of antibiotics. Some of the common ones are –

  1. Penicillin – It is used to treat many infections including ear infections and infections in respiratory tract.
  2. Carbapenems – they are highly potent antibiotics.
  3. Macrolides – it is an antibiotic used to treat skin infections, tissue infections and STDs.
  4. Tetracycline – it is used to treat urinary infections, skin infections, respiratory tract infections and infections by insects.
  5. Sulfonamides – they are used to treat meningitis and urinary tract infections.

Antibiotics come in different forms like ointments, creams, capsules and tablets.

Side effects of antibiotics

Just like any othter medication, antibiotics also cause side effects. Some of the common side effects are –

  • Cramps in stomach
  • Nausea and vomiting
  • Fever
  • Discharge from vagina
  • Allergies like swollen tongue, lips or face.
  • Blood in stool

Some of the less common side effects are –

  • Kidney stones
  • Abnormal clotting of blood
  • Photosensitivity
  • Blood disorders
  • Deafness
  • Bowel inflammation

In some people antibiotics may also cause allergic reactions, especially if it is antibiotics based on penicillin. The side effects may include swelling on tongue or face, rash and difficulty breathing. The allergic reactions to antibiotics can be delayed or immediate. If you think you suffer from any such allergic reaction, you should consult your doctor.

Most people experience mild side effects of antibiotics which usually disappear in few hours. However, sometimes the side effects can be severe like uncontrollable diarrhea or blood in stool. Also, some antibiotics do not seem to work or make you feel better if taken incorrectly. In such cases, consult a doctor.

People with kidney or liver problems should be very careful while using antibiotics. The type of antibiotics and its dosage can be affected due to their illness. Even pregnant women or breast-feeding women should talk to doctor before taking any kind of antibiotic.


When you are taking antibiotics, you should avoid taking any other medicines or herbal remedies without consulting your doctor. Certain antibiotics that are available over-the-counter can interact with antibiotics.

Some experts also suggest that certain antibiotics reduce the effectiveness of oral contraceptives, although, there is no particular research to support this.

Nevertheless, people who are suffering from diarrhea or vomiting or those who are not taking their oral contraceptives when they are ill due to their upset stomach might find that the effectiveness of oral contraceptives reduces. So, in that case people should take additional precautions.

How to consume antibiotics?

Usually antibiotics are taken by mouth. However, you can also take them through injections or they can be applied on your body with infection.

Most of the antibiotics control the infection within hours. You should always complete the course to avoid any re occurrence.

Avoid taking antibiotics with certain foods and drinks. Other antibiotics should be taken on empty stomach, an hour after meals or 2 hours after that. For the medicine to be effective, you need to follow the instructions correctly. Those who are taking metronidazole should avoid consuming alcohol, while those taking tetracyclines should avoid consuming dairy products as it might stop the medicine’s proper absorption.

How to stay healthy?

Here are few steps you can take to stay healthy and prevent yourself from getting sick.

  • Clean your hands.
  • When you sneeze or cough, cover your mouth.
  • Stay home and take rest when you are sick.
  • Avoid touching your nose, eyes, and mouth with unwashed hands.
  • Maintain a distance with people suffering from colds and upper respiratory infections.
  • Get your recommended vaccines.



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