Types of Antibiotics

Antibiotics Overview

They include a range of powerful drugs used to treat diseases caused by bacteria. Antibiotics cannot treat viral infections, such as cold, flu, and most coughs..

Not all infections are treated with antibiotics. While antibiotics may be effective against infections caused by bacteria (germs), they are not effective against viruses.

Like all drugs, antibiotics can have side effects and should be used only when necessary. Taking an antibiotic you don’t need can even be harmful. Because of this, there are important things to know about antibiotics.

• Antibiotics are among the most commonly prescribed drugs. However, up to 50% of all the antibiotics prescribed for patients are not needed nor as effective as hoped.
• The overuse of antibiotics is the single most important factor that has led to antibiotic resistance.
• Each year in the United States, at least 2 million people get serious infections with bacteria that are resistant to one or more of the antibiotics designed to treat those infections.
• At least 23,000 people die each year as a direct result of these antibiotic-resistant infections. Almost 250,000 people each year need hospital care for treatment of Clostridium difficile (C. difficile) infections.C Difficile infection is very difficult to treat. The use of antibiotics was the main reason why the illness developed. At least 14,000 people die each year in the United States from C. difficile infections. Many of these infections could have been prevented.

The overuse or inappropriate use of antibiotics gives bacteria a chance to adapt. When this happens, the antibiotics no longer work as well to treat the infection – the bacteria become “resistant” to antibiotics.

Antibiotics are powerful medications that treat certain infections and can save lives when used properly. They either stop bacteria from reproducing or destroy them.

Before bacteria can multiply and cause symptoms, the immune system can typically kill them. White blood cells (WBCs) attack harmful bacteria, even if symptoms occur, the immune system can usually cope and fend off the infection.

However, sometimes the number of harmful bacteria is excessive, and the immune system cannot clear them all. Antibiotics are useful in this scenario.

The first antibiotic was penicillin. Penicillin-based antibiotics, such as ampicillin, amoxicillin, and penicillin G, are still available to treat a variety of infections and have been in use for many years.

Several types of modern antibiotics are available, and they are usually only available with a prescription in the United States. Topical antibiotics are available in over-the-counter (OTC) creams and ointments.

How Antibiotics Work?

There are different types of antibiotics, which work in their unique way. However, the two main ways these work include the following:

• A bactericidal antibiotic, such as penicillin, kills the bacteria. These drugs usually interfere with either the formation of the bacterial cell wall or its cell contents.
• A bacteriostatic stops bacteria from multiplying.

It may take a few hours or days after taking the first dose before patients feel better and their symptoms improve.

Types of Antibiotics

There are several classes or groups of antibiotics, which depend on their chemical structure. Some classes of antibiotics include the following:

This above list is not inclusive, other classes and brand names exist. In addition, penicillins, cephalosporins, and other antibiotics may be regarded as subclasses of beta-lactam drugs. 

Antibiotic Safety

Antibiotics are powerful drugs that are generally safe. They are very helpful in fighting disease, but sometimes antibiotics can actually be harmful.

Following are key facts to know about antibiotic safety:

• Antibiotics can have side effects including allergic reactions and serious, possibly life-threatening diarrhea caused by the bacteria (germ) Clostridium difficile (C. diff). Antibiotics may also interfere with other drugs you may be taking.
• Side effects of antibiotics are responsible for almost one out of five emergency department visits. They are the most common cause of emergency department visits for children under 18 years of age.
• When you take an antibiotic you do not need, you are unnecessarily exposed to the side effects of the drug and do not get any benefit from it.

Taking an antibiotic you don’t need can lead to the development of antibiotic resistance. When resistance develops, antibiotics may not be able to stop future infections. Every time you take an antibiotic you don’t need, you increase your risk of developing a resistant infection in the future.

The bottom line: antibiotics come with benefits and risks. If you are prescribed an antibiotic, discuss the balance of benefits and risks with your doctor.

What do Antibiotics Treat?

A doctor prescribes antibiotics for the treatment of a bacterial infection. It is not effective against viruses.

Knowing whether an infection is bacterial or viral helps to treat it effectively.

Viruses cause most upper respiratory tract infections, such as the common cold and flu. Antibiotics do not work against these viruses.

If patients overuse antibiotics or use them incorrectly, the bacteria might become resistant. This means that the antibiotic becomes less effective against that type of bacterium, as the bacterium has been able to improve its defenses.

A doctor can prescribe a broad-spectrum antibiotic to treat a wide range of infections. A narrow-spectrum antibiotic is only effective against a few types of bacteria.

Some antibiotics attack aerobic bacteria, while others work against anaerobic bacteria. Aerobic bacteria need oxygen, and anaerobic bacteria do not.

In some cases, a doctor may provide antibiotics to prevent, rather than treat infection, as might be the case before surgery. This is the “prophylactic” use of antibiotics. Individuals  commonly use these antibiotics before bowel and orthopedic surgery.

Following are the types of infections that can be treated with antibiotics:

• Bacterial pneumonia
• Bladder and kidney infections
• Certain ear and sinus infections
• Clostridioides difficile
• Dental infections
• Skin infections
• Meningitis (swelling of the brain and spinal cord)
• Strep throat
• Whooping cough

Only bacterial infections can be killed with antibiotics. The common cold and flu, most coughs, some bronchitis infections, most sore throats, and the stomach flu are all caused by viruses. Antibiotics won’t work to treat them. Your doctor will tell you either to wait these illnesses out or prescribe antiviral drugs to help you get rid of them.

It’s not always obvious whether an infection is viral or bacterial. Sometimes your doctor will do tests before deciding which treatment you need.

Some antibiotics work on many different kinds of bacteria. They’re called “broad-spectrum.” Others target specific bacteria only. They’re known as “narrow-spectrum.”

Diseases Treated by Antibiotics

Viruses cause most upper respiratory infections, which include head colds, sore throats, bronchitis, and sinus infections. Viruses cannot be treated by antibiotics.

The common cold and influenza (flu) do not respond to antibiotics. Less than 10% of acute bronchitis cases are caused by bacteria. Most cases of acute ear infections also resolve without antibiotics.

Sore throats are usually caused by viruses as well. Antibiotics are not recommended unless you have strep throat. Only about 15% to 30% of sore throat cases in children and up to 10% of cases in adults are due to strep throat.

Almost all cases of acute bacterial sinusitis resolve without antibiotics.

The bottom line: Taking antibiotics for most acute upper respiratory tract infections does little or no good, and the downsides are real.

Side Effects of Antibiotics

Antibiotics commonly cause the following side effects:

• Diarrhea
• Nausea
• Rashes
• Sensitivity to sunlight, when taking tetracyclines
• With certain antibiotics or prolonged use, fungal infections of the mouth, digestive tract, and vagina
• Upset stomach
• Vomiting

Some unusual side effects of antibiotics include:

• Formation of kidney stones, when taking sulfonamides
• Hearing loss  when taking macrolides or aminoglycosides
• low platelet count, when taking cephalosporins, and penicillins, among others
• severe aches and pains, when taking fluoroquinolone
• Low granulocyte, a type of WBC count, when taking penicillin

Some patients, especially older adults  may develop C.difficile infection. They may experience bowel inflammation, which can lead to severe, bloody diarrhea.

• Allergic reactions: Every year, there are more than 140,000 emergency department visits for reactions to antibiotics. Almost four out of five emergency department visits for antibiotic-related side effects are due to an allergic reaction. These reactions can range from mild rashes and itching to serious blistering skin reactions, swelling of the face and throat, and breathing problems. Minimizing unnecessary antibiotic use is the best way to reduce the risk of side effects from antibiotics. You should tell your doctor about any past drug reactions or allergies.
• C. difficile: C. difficile is a type of bacteria (germ) that causes diarrhea linked to at least 14,000 American deaths each year. When you take antibiotics, good bacteria that protect against infection are destroyed for several months. During this time, you can get sick from C. difficile. The bacteria can be picked up from contaminated surfaces or spread from the healthcare environment. People, especially older adults, are most at risk who take antibiotics and also get medical care. Take antibiotics exactly and only as prescribed.
• Antibiotic resistance: The use of antibiotics may increase the risk of bacteria becoming resistant to them. Antibiotic-resistant infections can be very serious and difficult to treat

How Viruses are Treated?

Symptoms caused by viruses are usually treated with the over-the-counter drugs (drugs you can buy without a prescription). Some drugs reduce pain, such as acetaminophen (Tylenol). Other drugs help make breathing easier (decongestants), and or relieve sneezing and runny nose ( antihistamines). Symptoms can also be treated by gargling with salt water or drinking warm tea.

The best defense against getting the flu is to get a flu shot. The flu shot, however, does not protect against other viruses that cause other illnesses.

For some patients, a doctor may prescribe an antiviral drug, such as oseltamivir (Tamiflu). These patients have a confirmed diagnosis of the flu and have risk factors for flu-related complications.

These risk factors include the following:

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Heart, liver or kidney disease
• Age older than 65
• Living in a nursing home
• Weakened immune system due to cancer or HIV or organ transplantation – the immune system is the body’s defense system against infections

There are a few situations in which antibiotics are needed. See your doctor if you have a weakened immune system due to cancer, or if you are taking steroids, have HIV, or have had an organ transplant. Also call if your symptoms worsen or last longer than 7 to 10 days.

If you think you may be getting the flu and you already have these conditions, you may be less able to fight bacterial infections should they occur.

Drug Interactions

Antibiotics can interact with other drugs you take, making those drugs or the antibiotics less effective. Some drug combinations can worsen the side effects of the antibiotic or other drug.

Patients taking an antibiotic should not take other medicines or herbal remedies without speaking with a doctor first. Certain OTC medicines might also interact with antibiotics.

Some doctors suggest that antibiotics can reduce the effectiveness of oral contraceptives. However, research does not generally support this.

Nonetheless, people who experience diarrhea and vomiting or are not taking their oral contraceptive during illness due to an upset stomach might find that its effectiveness reduces.

In these circumstances, doctors may recommend individuals take additional contraceptive precautions.

Doctors may also advise avoiding alcohol for certain drugs, such as doxycycline. However, drinking alcohol in moderation is unlikely to cause problems with the most commonly used antibiotics.

Common side effects of antibiotics include nausea, diarrhea, and stomach pain. Sometimes these symptoms can lead to dehydration and other problems.

How to Use Antibiotics?

Patient’s usually take antibiotics orally by mouth. However, doctors can administer them by injection or apply them directly to the part of the body with infection.

Most antibiotics can start working within a few hours. Doctors advise people to complete the whole course of medication to prevent the return of the infection.

Stopping the medication before the course has finished increases the risk that the bacteria will become resistant to future treatments. The ones that survive will have had some exposure to the antibiotic and may consequently develop resistance to it.

An individual needs to complete the course of antibiotic treatment even after they notice an improvement in symptoms.

Doctors and the leaflet provided with the drug provide specific instructions on how to take the medication correctly.

People can follow some tips for using antibiotics effectively, such as:

• Avoiding alcohol when using metronidazole.
• Avoiding dairy products when taking tetracyclines, as these might disrupt the absorption of the medication.
• Taking the medication at the same time, or at set times in the day — this depends on how many times a day a person needs to take the drug.

 

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