The Facts About Antibiotics

Antibiotics can serve as a helpful defense against infections and diseases, but understanding when and how to use them is important for your safety and health.

Antibiotics are powerful medications used to treat countless illnesses, including urinary tract infections (UTIs) and sexually transmitted infections (STIs). While antibiotics are the most commonly prescribed drugs, they are effective only in fighting bacteria, not viruses. 

Generally, antibiotics are safe. However, it's vitally important to use them only at the direction of your doctor. Taking antibiotics you don't need can be harmful to your health, and misusing antibiotics can lead to antibiotic resistance, making future infections more difficult to treat.

While the number of antibiotics used to treat bacterial infections rank in the hundreds, most of them fall into one of the following groups:

• Penicillins. These are commonly used to treat chest, skin and urinary tract infections. Penicillins include drugs such as penicillin, amoxicillin and flucloxacillin.
• Cephalosporins. This group of antibiotics is used to treat a vast number of infections, including more severe infections like meningitis.
• Tetracyclines. This group of antibiotics—which includes tetracycline, doxycycline and lymecycline—is used for common issues such as acne and rosacea. 
• Macrolides. Antibiotics in this group are often used for lung and chest infections.  
• Aminoglycosides. The use of these drugs is typically reserved for hospital settings to treat grave illnesses, such as sepsis. Aminoglycosides can cause serious side effects. 
• Fluoroquinolones. These were once used to treat a wide array of infections but are now used less because of the risk of serious side effects. 

Penicillins, cephalosporins and tetracyclines are the most commonly used types of antibiotics.

Antibiotics can come in the form of capsules, tablets or liquids to be swallowed or injected. For eye or ear infections, antibiotics may be administered as creams, sprays, drops or lotions. 

When you've been prescribed an antibiotic, it's important to be aware of any potential side effects. Additionally, it's essential that you finish your entire prescription as directed even if you start to feel better. Discontinuing the use of antibiotics prematurely can cause a resurgence in infection and make it more resistant to treatment in the future.

According to Germany's Institute for Quality and Efficiency in Health Care, your doctor or pharmacist can tell you what you can eat and drink while taking antibiotics, when and how often you should take them, and whether they can be taken with other medications. It's also important to take antibiotics as directed. For instance, breaking up large tablets into smaller pieces may make them easier to swallow but could potentially prevent the antibiotics from working as designed.

Different antibiotics work in different ways. Some antibiotics treat infections by killing the germs that cause them. In many cases, the infection-causing bacteria are killed when the antibiotic compromises the structure of its cell wall. In other instances, antibiotics work by simply preventing the harmful bacteria from reproducing and spreading.

Antibiotics can treat certain bacterial infections, though not every bacterial infection requires antibiotic treatment. Antibiotics are usually necessary if an infection is unlikely to go away or will take too long to go away without them; if other people could be easily infected; or if there's a high risk the infection could cause serious complications, according to the United Kingdom's National Health Service. 

In some cases, antibiotics may be used as preventive treatments for high-risk individuals. 

Infections that can be treated with antibiotics include:

• Bacteria-caused STIs, such as syphilis, chlamydia, and gonorrhea
• Bacterial pneumonia
• Bacterial prostatitis
• Bacterial vaginosis
• Epididymitis
• Sepsis
• Strep throat
• UTIs
• Whooping cough

Bacteria-caused STIs, such as gonorrhea, chlamydia and syphilis, can be treated with antibiotics—this has long been known. But recent research found a single dose of doxycycline (a cheap and accessible antibiotic), when taken within 72 hours of unprotected sex, can help greatly reduce occurrences of bacterial STIs. 

Antibacterial medications can also help with a host of other sexual health problems. Bacterial vaginosis, while not technically an STI (though you're more likely to get it if you're sexually active), is highly treatable. In December 2021, the Food and Drug Administration (FDA) approved a one-dose treatment of an antibiotic vaginal gel (brand name Xaciato) containing clindamycin phosphate. 

If other conditions such as acute bacterial prostatitis, epididymitis and UTIs are affecting your sexual health, the good news is that they, too, can be effectively treated with antibiotics, though some infections may be more resistant to treatment and may take longer to eliminate.

Antibiotics can only stop infections caused by bacteria, which means they are ineffective in killing viruses. Common viruses include colds, sinus infections, flu and sexually transmitted diseases (STDs), including herpes and HIV. Antibiotics are also powerless against virus-caused stomach bugs that lead to vomiting or diarrhea. As for respiratory conditions like asthma, antibiotics are not necessary because respiratory symptoms are not caused by bacteria. However, antibiotics may be necessary for a person whose asthma symptoms are made worse by a bacterial infection in the chest. 

Antibiotics are powerful, but so are the infections they fight. Antibiotic resistance is increasingly considered a global health threat as the overuse and misuse of antibiotics have triggered mutations in bacteria that make them resistant to antibiotic treatment. For example, antibiotic-resistant STDs, particularly gonorrhea, are becoming a problem. According to experts, most STDs are still treatable with common antibiotics, but places like Southeast Asia and the Pacific regularly report cases of gonorrhea that are considered untreatable because the strain of gonorrhea is resistant to antibiotics. It's worth noting that while instances of "super gonorrhea" are still relatively rare and found only in specific regions, they are gradually increasing in Western Europe and the U.S. as well. 

Considering antibiotics may not be the best long-term solution for certain STDs, experts have warned that practicing safer sex is more important than ever.

Whenever a medication is used, there is always the possibility of side effects. This applies to antibiotics as well. Antibiotics can commonly cause: 

• Diarrhea
• Nausea
• Rashes
• Yeast infections 

Side effects can range in severity and some may lead to serious health complications. If you experience any side effects while taking antibiotics, you should consult your doctor immediately.

Any time a doctor prescribes antibiotics, you should first discuss any over-the-counter or prescription drugs you're currently taking in case there are any known problematic interactions. This is important because some antibiotics can lead to complications or serious side effects if mixed with other medications or taken while drinking alcohol. 

Certain antibiotics may make your birth control less effective. Talk with your doctor about how your antibiotics may affect your contraception and how you can better protect yourself while taking antibiotics.

What sexual health issues do antibiotics treat?

Bacteria-caused STIs, such as gonorrhea, chlamydia and syphilis, can be treated with antibiotics. Recent research has also found that you may decrease your risk for developing these STDs if you take an antibiotic called doxycycline within three days of having unprotected sex. Other issues that may affect your sexual health—including bacterial vaginosis, acute bacterial prostatitis, epididymitis and UTIs—can also be treated with antibiotics.

What are the most common side effects of antibiotics?

The most common side effects of antibiotics include the development of a rash, nausea, diarrhea or yeast infection. Side effects can range in severity and some may lead to serious health complications. If you experience any side effects while taking antibiotics, you should consult your doctor immediately.

Can antibiotics cause erectile dysfunction?

Though many medications, including those for depression and high blood pressure, have side effects that potentially include erectile dysfunction (ED), there is little evidence to support the idea that antibiotics cause ED. If you're experiencing erectile dysfunction, talk to your doctor to learn more about potential treatments.