Antibiotics are commonly prescribed medications used to treat bacterial infections. They work by killing or stopping the growth of bacteria that cause illness. While antibiotics are effective at treating infections, they can interact with other medications a person may be taking. Some drug combinations can increase side effects of antibiotics or make them less effective. Knowing what medications should not be mixed with antibiotics is important for patient safety.
How do antibiotics work?
Antibiotics stop bacteria from multiplying by interfering with bacterial cell processes. Different classes of antibiotics work in different ways:
- Penicillins and cephalosporins – Interfere with bacterias cell wall formation
- Fluoroquinolones – Block bacterial DNA replication and repair
- Macrolides – Prevent bacterial protein production
- Tetracyclines – Inhibit bacterial protein synthesis
- Aminoglycosides – Disrupt bacterial protein synthesis
- Sulfonamides – Interfere with bacterial folic acid synthesis
By disrupting these critical bacterial functions, antibiotics are able to eliminate infections or stop them from spreading further in the body. The specific antibiotic prescribed depends on the type of bacteria causing the infection.
Why antibiotics should not be mixed with some medications
While antibiotics are effective at killing bacteria, they can interact with other substances in the body, including some medications a person might be taking. Some key reasons antibiotics should not be mixed include:
- Decreased antibiotic effectiveness – Some drugs can interfere with how well antibiotics work to kill bacteria. This can prevent the antibiotic from eliminating the infection.
- Increased side effects – Antibiotics and other medications taken together can sometimes increase the risk of adverse side effects. This includes things like nausea, diarrhea, and central nervous system disturbances.
- Drug toxicity – Certain combinations of antibiotics and other drugs can increase the risk of experiencing toxic drug levels. This occurs when drug levels build up to excessive amounts in the bloodstream.
- Changes in gut bacteria – Antibiotics disrupt the normal gut microbiome. Taking other medications at the same time may compound these gut bacteria changes.
- Kidney problems – Some antibiotics and medications taken together can increase the risk of kidney injury or kidney failure.
Due to these potential issues, caution should be taken when mixing antibiotics with certain types of medications.
Drugs that should not be taken with common antibiotics
There are many types of medications that should be avoided when also taking common antibiotic prescriptions. Some key examples include:
Penicillins
Penicillin antibiotics like amoxicillin should not be mixed with:
- Probenecid – Increases penicillin blood levels
- Allopurinol – Increased risk of skin rash
- Blood thinners like warfarin – Can increase warfarin effects
- Methotrexate – Increases methotrexate toxicity
- Tetracyclines – Decreased penicillin efficacy
Cephalosporins
Cephalosporin antibiotics like cephalexin should not be mixed with:
- Probenecid – Increases cephalosporin blood levels
- Blood thinners like warfarin – Can increase warfarin effects
- Loop diuretics like furosemide – Increased risk of kidney problems
- Tetracyclines – Decreased cephalosporin efficacy
Fluoroquinolones
Fluoroquinolone antibiotics like ciprofloxacin should not be mixed with:
- Theophylline – Increased theophylline levels and side effects
- Caffeine – Increased caffeine levels and side effects
- Antacids with aluminum, calcium, magnesium – Decreased fluoroquinolone absorption
- Warfarin – Increased warfarin levels and bleeding risk
- Corticosteroids like prednisone – Increased risk of tendon rupture
Macrolides
Macrolide antibiotics like erythromycin should not be mixed with:
- Theophylline – Increased theophylline levels
- Warfarin – Increased warfarin levels and bleeding risk
- Cyclosporine – Increased cyclosporine toxicity
- Statins like atorvastatin – Increased statin toxicity
- Digoxin – Increased digoxin levels
Tetracyclines
Tetracycline antibiotics should not be mixed with:
- Antacids with aluminum, calcium, magnesium – Decreased tetracycline absorption
- Iron supplements – Decreased tetracycline absorption
- Zinc supplements – Decreased tetracycline absorption
- Penicillins – Decreased efficacy of both antibiotics
- Retinoids like isotretinoin – Increased intracranial hypertension risk
Aminoglycosides
Aminoglycoside antibiotics like gentamicin should not be mixed with:
- Amphotericin B – Increased risk of hearing loss and kidney damage
- Loop diuretics like furosemide – Increased risk of hearing loss and kidney damage
- Vancomycin – Increased risk of hearing loss and kidney damage
- NSAIDs like ibuprofen – Increased risk of kidney damage
Sulfonamides
Sulfonamide antibiotics like Bactrim should not be mixed with:
- Methotrexate – Increased methotrexate toxicity
- Blood thinners like warfarin – Increased warfarin effects
- Oral hypoglycemics like glimepiride – Increased risk of low blood sugar
- Potassium supplements – Increased potassium levels
Medications to avoid with multiple antibiotic types
In addition to the drug interactions above, there are some medications that should be avoided with multiple different antibiotic classes:
- Probenecid – Avoid taking with penicillins, cephalosporins, tetracyclines, and sulfonamides. It increases blood levels of these antibiotics and toxicity risk.
- Warfarin – Avoid taking with penicillins, cephalosporins, fluoroquinolones, macrolides, and sulfonamides. These antibiotics can increase warfarin levels and bleeding risk.
- Theophylline – Avoid taking with fluoroquinolones and macrolides, which can increase theophylline levels and side effects.
- Corticosteroids – Avoid taking with fluoroquinolones. Increased risk of tendon damage.
- NSAIDs – Avoid taking with aminoglycosides. Increased risk of kidney injury.
Foods and beverages that should not be consumed with antibiotics
In addition to other medications, there are some foods and drinks that should be avoided when taking certain antibiotics:
- Dairy – Avoid consuming dairy products like milk, yogurt, and cheese within 2 hours of taking tetracyclines and fluoroquinolones. Dairy reduces antibiotic absorption.
- Caffeine – Avoid caffeine when taking fluoroquinolones as it may increase side effects.
- Grapefruit – Avoid grapefruit and grapefruit juice when taking macrolides like erythromycin. Grapefruit increases levels of these antibiotics.
- Alcohol – Avoid alcohol when taking metronidazole, tinidazole, linezolid, and cephalosporins like cephalexin. Alcohol causes reactions when mixed with these antibiotics.
- High fiber foods – Avoid high fiber foods within a few hours of taking fluoroquinolones, tetracyclines, and penicillins. Fiber can decrease antibiotic absorption.
Who is at highest risk for antibiotic drug interactions?
Certain groups of people may be at increased risk for experiencing problematic antibiotic drug interactions or side effects:
- Older adults – Increased potential for kidney dysfunction, which may increase the toxicity of aminoglycosides, vancomycin, and more.
- Children – Still developing organs like the kidneys, which may be more vulnerable to toxicity from certain antibiotics.
- Pregnant women – Some antibiotics have been associated with risks during pregnancy. Close monitoring is required.
- People with kidney disorders – Decreased kidney function increases the risk of toxicity from antibiotics like aminoglycosides.
- People taking multiple medications – The more medications a person takes, the higher the chance for an interaction with antibiotics.
Doctors should carefully evaluate medication lists when prescribing antibiotics for high-risk individuals and monitor them closely for adverse reactions.
How to safely take antibiotics with other medications
If you need to take antibiotics along with other mediations, there are some steps you can take to reduce your risk of problematic drug interactions:
- Talk to your doctor – Discuss all medications and supplements you take to allow assessment of potential interactions.
- Take antibiotics properly – Follow prescribed antibiotic dosage schedules closely to keep consistent levels in your bloodstream.
- Space out doses – Take antibiotics and other medications at least 2 hours apart whenever possible.
- Monitor for side effects – Watch for signs of antibiotic toxicity like nausea, diarrhea, dizziness, rash, etc. Report concerns.
- Stay hydrated – Drink plenty of fluids to help your kidneys eliminate antibiotics and decrease side effect risks.
- Avoid grapefruit – Do not eat grapefruit or drink grapefruit juice, as it can affect many different medications.
Carefully following dosing schedules, being aware of possible interactions, and staying in touch with your doctor can go a long way in preventing complications when taking antibiotics alongside other medications. Report any concerns immediately.
Key points and summary
– Antibiotics can interact with many other types of medications, increasing side effects or decreasing effectiveness. It is important to know what drugs should not be taken at the same time as antibiotics.
– Mixing antibiotics with probenecid, warfarin, theophylline, NSAIDs, diuretics, or vitamins/minerals can be problematic. Each antibiotic class also has specific medications that should be avoided.
– Certain foods and beverages like dairy, caffeine, alcohol and grapefruit juice can interact with antibiotics as well.
– Older adults, children, pregnant women, kidney disease patients, and those on multiple medications have increased risk for drug interactions with antibiotics.
– To use antibiotics safely, take steps like spacing out doses, monitoring side effects closely, staying hydrated, and discussing all medications with your doctor. This can reduce the risks of negative antibiotic drug interactions.
Conclusion
Antibiotics are commonly used and effective medications for treating bacterial infections. However, they can interact with many other drugs a person might be taking, increasing side effects or decreasing antibiotic effectiveness. There are certain antibiotics that should not be taken with specific types of medications, including probenecid, warfarin, NSAIDs, and more. Certain foods and drinks should also be avoided when taking some antibiotics. People taking multiple medications or with conditions like kidney disease require extra caution as well. By being aware of potential medication and food interactions with antibiotics, closely following dosing schedules, and monitoring side effects, patients can reduce their risk for negative reactions and get the most out of their antibiotic treatment.