Are antibiotics dangerous?

Q: Are antibiotics dangerous?

Krishna: Not really. Most of them are safe. However, common antibiotics carry small but serious risks of life-threatening drug reactions. Let me explain using a recent study.

Two classes of commonly prescribed oral antibiotics are associated with the greatest risk for severe drug rashes that can lead to emergency department visits, hospitalizations and even death, according to a new study.  So scientists suggest that prescribers should consider using lower-risk antibiotics for their patients when clinically appropriate.

Serious cutaneous adverse drug reactions (cADRs), or severe drug rash, are a group of rare but potentially life-threatening delayed reactions involving the skin and, often, internal organs. Some of these reactions carry mortality rates from 20 to 40%. While many different classes of drugs can cause serious cADRs, antibiotics are among the most commonly reported triggers for these reactions.

Clinicians have speculated that certain antibiotics carry greater risk for these severe reactions, but no study has ever confirmed these claims. 

The objective of this new work was to explore the risk for cARDs in a population of older adults, who tend to receive disproportionately more antibiotic prescriptions than younger adults.

The study, "Oral antibiotics and the risk of serious cutaneous adverse drug reactions," was published in JAMA. The case-control study used health care data from ICES of adults 66 years or older who received a prescription for at least one oral antibiotic between 2002 and 2022 in Ontario, Canada.

Over the study period, 21,758 adults had an ED visit or hospitalization for a serious cADR following oral antibiotics and were matched with 87,025 controls who did not have a reaction.

The good news is that most patients who visited the hospital with these reactions were discharged without being admitted, so that should be reassuring to providers and patients.

However, of those who were admitted to hospital with the most severe reactions, 20% were treated in the ICU, and 5% of hospitalized patients died, which underscores the need for careful prescribing practices.

The most commonly prescribed antibiotics were penicillins (29%), followed by cephalosporins (18%), fluoroquinolones (17%), macrolides (15%) nitrofurantoin (9%) and sulfonamides (6%). Less commonly prescribed antibiotics were grouped together and accounted for 7% of prescriptions.

Key findings of this  study  include:

• All antibiotics were associated with a higher risk of serious cADRs relative to macrolides, but sulfonamides ("sulfa drugs") and cephalosporins were associated with the highest risk.

• There were two cADR-related hospital visits for every 1,000 antibiotic prescriptions dispensed.

• About one in eight patients presenting to the ED with antibiotic-related cADRs were hospitalized, likely because their reactions were more severe or because of concerns about potential complications.

• 20% of hospitalized patients with the most severe forms of cADRs were treated in a critical care unit, and 5% of those patients died.

While rare, these severe drug reactions can be life-threatening. Patients should be aware of rash, fever, and other symptoms, which can start weeks after a prescription has been started and even after the course of antibiotics has stopped. 

It's also one more reason why antibiotics should be prescribed only when they're truly needed.

Oral Antibiotics and Risk of Serious Cutaneous Adverse Drug Reactions, JAMA (2024). DOI: 10.1001/jama.2024.11437

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Additional information:

Antibiotics are generally safe, and doctors prescribe them to stop the growth of bacteria; for example, to treat bacterial infections, such as strep throat, urinary tract infections (UTIs), and certain skin infections.
Antibiotics do not work against viruses that cause most upper respiratory infections, the common cold, or COVID-19. So there is no need to take antibiotics when you have a viral infection. 
However, antibiotics can cause some side effects, ranging from minor to severe to life threatening.  One in five medication-related emergency room visits are due to antibiotic side effects.

Anyone experiencing a severe antibiotic side effect should consult with a healthcare professional. A person experiencing anaphylaxis symptoms, such as difficulty breathing, chest pain, or tightness in the throat, should call emergency services.

Whenever a person takes an antibiotic, they may experience some common side effects, such as:

Digestive problems that  may include: nausea, indigestion, vomiting, diarrhea, bloating or feeling full
loss of appetite, stomach pain or cramping.
Sometimes, a person needs to take antibiotics with food; other times, they need to take them on an empty stomach. A person can speak with their doctor or a pharmacist about how best to take their antibiotic.

Most digestive problems go away once a person stops taking the antibiotic.

Persons with digestive side effects, such as bloody diarrhea, severe abdominal pain, or uncontrollable vomiting, should stop taking their antibiotics and immediately contact a doctor.
Antibiotics are drugs that kill harmful bacteria. However, they sometimes kill the good bacteria that protect people from fungal infections and upset the natural balance of the body’s natural flora.

As a result of this imbalance, taking antibiotics may lead to a fungal (candida) infection of the mouth, digestive tract, or vagina.

Candidiasis in the mouth and throat is also called thrush.

Symptoms of thrush may include: 

white patches on the throat, cheeks, roof of the mouth, or tongue
pain while eating or swallowing
bleeding with tooth brushing

Doctors usually prescribe antifungal medications such as nystatin to treat fungal infections.
Treating a UTI with antibiotics can sometimes lead to a vaginal yeast infection.

Symptoms of a vaginal yeast infection may include:

vaginal itchiness, swelling, and soreness
pain and a burning sensation during intercourse and when peeing
abdominal or pelvic pain
blood in the urine
white-to-grey lumpy vaginal discharge
fever and chills

Doctors often prescribe the antifungal drug fluconazole to treat yeast infections caused by UTI antibiotics.
Drug interactions: Certain antibiotics may interact with a person’s other medicines or supplements.

The symptoms of drug interactions range from mild to life threatening. Some common warning signs after taking the medication include:

feeling nauseous
feeling either very tired or very energetic

Drug interactions may make an antibiotic less effective or increase the action of a particular drug.

It is generally a good idea to avoid alcohol while taking antibiotics. Drinking alcohol while on certain antibiotics can decrease the effectiveness and increase the chance of antibiotic side effects.

Antibiotics that may interact with alcohol include: doxycycline, erythromycin, metronidazole, tinidazole, isoniazid

To help avoid antibiotic drug interactions, people should always review newly prescribed medications with their doctor or pharmacist. Patient education inserts also list any drugs that might interact with the prescribed antibiotic.

Rare and more severe side effects:
Some of the more serious side effects associated with antibiotics include:

Anaphylaxis
In rare cases, antibiotics can cause an extremely severe allergic reaction known as anaphylaxis.

Signs of anaphylaxis include: a rapid heartbeat, when a person’s resting heartbeat is greater than 60–100 beats per minute, hives or a red, itchy rash, feelings of uneasiness and agitation, tingling sensations and dizziness,swelling of the face, mouth, and throat, rapid swelling of the lips or under the skin, severe wheezing, coughing, or trouble breathing, low blood pressure, fainting, seizures.

Anaphylaxis can be fatal without immediate emergency care. If people suspect anaphylaxis, they should dial the emergency services or go to the emergency room right away.

The kidneys usually clear many antibiotic medications.

When the kidneys are not working correctly, these medications can build up and lead to further kidney damage.

Doctors often check kidney function blood tests before prescribing antibiotics for individuals with kidney disease.

Long term side effects of antibiotics:
According to some studies, long term side effects of antibiotics in adult females have links to changes in the gut microbiota. This change has links to risks of various chronic diseases, such as cardiovascular disease and certain types of cancer.

These studies also states that the length of antibiotic exposure may be a risk factor for premature death.

Additional research also found that prolonged exposure to antibiotic therapy has associations with an increased risk of gastrointestinal issues in premature babies, late-onset sepsis, or death among very low birth weight infants.

Conclusion: 

Antibiotics are prescription medications that kill or prevent bacteria from growing. Doctors prescribe antibiotics to treat bacterial infections.

Antibiotics commonly produce side effects that range from mild to severe, so a person should only take them when a doctor deems them necessary.

People should report any antibiotic side effects to their doctor or healthcare professional immediately.

If you take these things into account and take precautions, antibiotics are safe to use when prescribed by a qualified medical doctor.