Basics
1. What are antibiotics, and how do they work?
Antibiotics are medicines that kill bacteria or stop them from multiplying. They act on bacterial cell walls, proteins, DNA, or metabolism. Because human cells differ, antibiotics can target bacteria selectively. Read more in Antibiotics basics.
2. Do antibiotics kill viruses?
No. Antibiotics have no effect on viruses such as influenza, colds, or COVID-19. Using them for viral infections only causes harm and increases resistance. See When not to use antibiotics.
3. What are the main classes of antibiotics?
They include penicillins, cephalosporins, macrolides, tetracyclines, fluoroquinolones, sulfonamides, nitroimidazoles, and nitrofurans. Each has its own spectrum and indications. An overview is available in Antibiotic classes.
4. Why do I need a prescription for antibiotics?
Because the wrong drug, dose, or duration can make an infection worse, cause side effects, or promote resistance. Doctors tailor antibiotics to the infection and patient factors. See Antibiotics basics.
5. Can antibiotics be bought online legally?
Yes, but only with a valid prescription. Telemedicine services can provide safe access, while unverified sellers may be illegal or unsafe. Learn more in Is it legal to buy antibiotics online.
Use and Dosage
6. For which illnesses are antibiotics prescribed?
They are used for bacterial infections: pneumonia, urinary tract infections, bacterial sinusitis, strep throat, skin infections, and more. Not all coughs or fevers require antibiotics. Full guide: Indications by condition.
7. How are dosages chosen for adults?
Doses depend on the drug, infection site, kidney/liver function, and local guidelines. Standard regimens exist, but self-adjustment is unsafe. Details in Dosing adults.
8. How are dosages calculated for children?
Usually by weight (mg/kg). Children also often receive suspensions instead of tablets. Precision is vital, underdosing or overdosing is risky. See Dosing children.
9. What forms do antibiotics come in?
Tablets, capsules, suspensions, injections, creams, and eye/ear drops. Each form suits different infections and patients. See overview in Antibiotic forms.
10. Should I take antibiotics with food or on an empty stomach?
It depends on the drug. Some absorb better on an empty stomach, while others are easier on the stomach with food. Instructions vary. Be sure to check How to take antibiotics.
11. What happens if I miss a dose?
Take it as soon as you remember, unless it’s almost time for the next one. Don’t double up. See dosing advice in How to take antibiotics.
12. Can I drink alcohol while taking antibiotics?
With most antibiotics, moderate alcohol doesn’t stop them working, but it may worsen side effects. With Metronidazole, alcohol is strictly forbidden due to dangerous reactions.
Safety and Side Effects
13. What are the most common side effects of antibiotics?
Stomach upset, nausea, diarrhea, rashes, and yeast infections are the most frequent. Most are mild and pass when treatment ends. Details in Antibiotic side effects.
14. What should I do if I get diarrhea while on antibiotics?
Mild diarrhea is common. Severe, watery, or bloody diarrhea, especially with fever, may signal C. difficile infection. Seek medical help. See Gut microbiome.
15. How do I know if I’m allergic to antibiotics?
Allergies can cause rashes, itching, swelling, or breathing problems. True penicillin allergy is often overdiagnosed. Learn to distinguish allergy from side effects at Allergic reactions.
16. Are antibiotics safe during pregnancy or breastfeeding?
Some are, some aren’t. Tetracyclines and fluoroquinolones are avoided, while many penicillins are safe. Always consult your doctor. More in Pregnancy and breastfeeding.
17. Which antibiotics interact with other medicines?
Several do, for example, macrolides may interact with statins, and tetracyclines with antacids or iron. See Drug interactions for details.
18. When should I seek emergency help while on antibiotics?
If you develop sudden breathing problems, swelling, severe diarrhea, yellowing of skin/eyes, tendon pain, or hearing loss. Red flags explained in Antibiotic side effects. If these occur while on antibiotics, seek urgent care.
Resistance
19. What is antibiotic resistance?
It’s when bacteria adapt and no longer respond to antibiotics that once killed them. This makes infections harder to treat and spreads globally. Basics: What and why.
20. Which infections are often resistant?
Urinary tract infections, skin/soft tissue infections, and some respiratory illnesses increasingly show resistant bacteria. Examples: Common resistant infections.
21. How can I reduce the risk of resistance?
Take antibiotics only as prescribed, finish the course, and never share leftovers. Practical steps in How to reduce resistance. These behaviors lower the risk of resistance.
22. Why shouldn’t I keep leftover antibiotics?
Because using them later may mean wrong drug, wrong dose, or incomplete treatment — fueling resistance. More at Antibiotic stewardship.
Specific Drugs
23. What is amoxicillin usually prescribed for?
Amoxicillin treats ear, throat, sinus, chest, and urinary infections. It’s one of the most common first-line antibiotics. Full guide: Amoxicillin.
24. When is azithromycin (Sumamed) used?
Often for respiratory infections, chlamydia, and traveler’s diarrhea. It’s valued for short courses and convenient dosing. See Azithromycin.
25. What is doxycycline good for?
A versatile antibiotic used for acne, pneumonia, tick-borne diseases, and malaria prevention. More in Doxycycline.
26. Is cephalexin similar to penicillin?
Yes, both are beta-lactams. Cephalexin is widely used for skin, urinary, and respiratory infections. Details at Cephalexin.
27. When do doctors prefer amoxicillin-clavulanate over plain amoxicillin?
When resistance is suspected, such as in sinusitis, recurrent ear infections, or bite wounds. Learn more at Amoxicillin-clavulanate.
28. Why is metronidazole special about alcohol?
Combining them can cause nausea, vomiting, and flushing. Strictly avoid alcohol during treatment. See Metronidazole.
29. Is nitrofurantoin only for cystitis?
Yes, it’s concentrated in the bladder, so it’s ideal for uncomplicated cystitis but not for kidney or systemic infections. Full info: Nitrofurantoin.
Buying Antibiotics
30. How can I tell if an online pharmacy is safe?
Look for license information, real pharmacist support, and a requirement for prescriptions. Avoid sites selling antibiotics freely. Checklist: Safe pharmacy checklist.
31. How does telemedicine for antibiotics work?
You complete a questionnaire, consult a licensed doctor online, receive an electronic prescription, and collect the medicine at a pharmacy or by delivery. Process explained in Telemedicine process.
32. Why do antibiotic prices differ so much online?
Costs vary by brand vs. generic, dosage, insurance coverage, and delivery. Guidance at Pricing and insurance.
33. How can I avoid scams when buying antibiotics?
Be wary of websites offering “no-prescription” sales or very low prices. Counterfeits and unsafe drugs are common. Safety tips at Risky offers and scams.