Author
Bowtie Team
Updated on
2025-07-28
Disclaimer: This article is translated with the assistance of AI.
Antibiotics are a go-to prescription from doctors, but what conditions do they really treat? Can they tackle colds and flu? What side effects should you watch for, and what precautions are key? Join Bowtie as we break it all down!
What Are Antibiotics? For Bacterial Infections Only?
Antibiotics are medications used to treat bacterial infections. They work by destroying the bacterial cell walls, thereby killing the bacteria or preventing their reproduction 1 . Different types of antibiotics can treat various bacterial infections, such as urinary tract infections, middle ear infections, acne, meningitis, certain types of diarrhea, and pneumonia 2 .
However, antibiotics are not suitable for treating viral infections like the common cold or flu 3 . Bacteria are microorganisms that can reproduce independently, while viruses are much smaller and require host cells from other organisms to multiply. Due to these differences, the diseases they cause and the medications used to treat them also vary.
Many human infections are caused by bacteria, but not all bacteria lead to illness. Some bacteria naturally reside in the human body, and when harmful microbes invade or immunity weakens, the bacterial balance can be disrupted, leading to infection. In such cases, antibiotics may be used for treatment.
When Do You Need Antibiotics?
As mentioned above, antibiotics are needed only for bacterial infections. Common bacterial infections include those in the ears, chest, urinary system, skin, secondary bacterial infections, post-surgical bacterial infections, and certain sexually transmitted diseases like chlamydia 1 .
Some bacterial infections can resolve on their own without medication. Therefore, doctors will assess and monitor the condition before deciding if antibiotics are necessary.
Doctors may take samples of blood, urine, stool, or mucus, or perform swab tests from the throat or skin to diagnose the type of bacterial infection and prescribe the most effective antibiotic.
It’s worth noting that most upper respiratory infections (like colds) or gastroenteritis are viral and not suitable for antibiotic treatment 3 .
Antibiotics vs Anti-Inflammatory Drugs
Antibiotics are not anti-inflammatory drugs, but they can alleviate inflammation caused by bacterial infections by killing the offending bacteria. Anti-inflammatory drugs generally refer to pain-relieving medications that reduce inflammation symptoms, with effects and mechanisms different from antibiotics 4 .
Common Oral Antibiotics
| Types | Effects | Applicable Conditions |
| Penicillins and Derivatives 5 | Kill bacteria by interfering with bacterial cell wall synthesis | Urinary tract infections, middle ear infections, sinusitis, bronchitis, oral infections, and pneumonia |
| Cephalosporins 5 | Acute sinusitis, bronchitis, community-acquired pneumonia, acute middle ear infections, sinusitis, urinary tract infections, and skin infections | |
| Macrolides 5 | Kill bacteria or inhibit their growth and reproduction | Middle ear infections and pneumonia, often used for patients allergic to penicillin |
| Tetracyclines and Derivatives 6 | / | Various bacterial infections or severe acne |
| Sulfonamides 6 | / | Urinary tract infections and bronchitis |
| Quinolones | Synthetic antibiotics | Broad range of bacterial infections, such as urinary tract infections and respiratory infections |
Can Antibiotics Lead to Resistance?
Antibiotic resistance (also known as drug resistance) occurs when bacteria mutate and become immune to antibiotics that were once effective, making it impossible for the drugs to control similar infections. Once bacteria develop resistance to multiple common antibiotics, they become “superbugs” or “multidrug-resistant bacteria,” leading to severe infections 2,3 .
Professor Yuen Kwok-yung, Chair of the Expert Committee on Antimicrobial Resistance, has pointed out that Hong Kong’s antibiotic resistance is five times higher than in other advanced countries. For example, with Staphylococcus aureus, Hong Kong’s resistance rate is nearly 50%, compared to just 10% in the UK and under 5% in Sweden 7 .
Side Effects of Antibiotics
Different antibiotics have various side effects, with common ones including nausea, vomiting, constipation, diarrhea, and headaches 1,3 . Some people may even experience allergic reactions, such as rashes, itching, or difficulty breathing. If symptoms are severe or persistent, seek medical attention immediately.
Certain antibiotics can cause more serious side effects, including kidney problems, blood abnormalities, sensitivity to sunlight, and hearing loss, though these are relatively rare.
Who Should Avoid Antibiotics?
Some antibiotics can reduce the effectiveness of oral contraceptives, affect fetal development, or impact infant health. Therefore, women who are using contraception, pregnant, or breastfeeding should consult a doctor before taking medication 2,3 .
Since antibiotics can trigger allergic reactions, individuals with a history of allergies—such as asthma, eczema, or hay fever—should inform their doctor about these conditions so that appropriate medication can be prescribed.
Additionally, patients with liver disease, impaired kidney function, or myasthenia gravis should avoid specific classes of antibiotics 8 .
How to Take Antibiotics Correctly?
To avoid developing resistance or side effects, patients should follow their doctor’s instructions and complete the full course of antibiotics, even if symptoms improve—don’t stop on your own 2 . It’s best to take them at the same time each day, avoid doubling doses, and never buy or take antibiotics without a prescription 5 .
During treatment, avoid alcohol, taking multiple medications, or herbal remedies, as they may affect the drug’s efficacy or cause side effects. Before taking other medications, consult the prescribing doctor 1 .
Additionally, dairy products, fruit juices, and foods containing calcium or magnesium salts may interfere with antibiotic effectiveness, so check what to avoid before taking them 8 .
How to Store Antibiotics Properly?
Patients should store antibiotics properly according to the instructions on the label, in a cool, dry place out of children’s reach. If the label specifies refrigeration, store them in the fresh food compartment—do not put them in the freezer 3 .
References
- 1 Cleveland Clinic. “Antibiotics: When You Need Them and What to Expect.” Cleveland Clinic, 24 May 2023
- 2 WebMD. “What Are Antibiotics?” WebMD, WebMD, 24 Feb. 2017
- 3 Drug Office, Department of Health. “Antibiotics” Drug Office, Department of Health, Dec. 2022
- 4 Health Direct Australia. “Anti-Inflammatory Medicines (NSAIDs).” Www.healthdirect.gov.au, 2 Sept. 2020
- 5 NHS . “Antibiotics.” Antibiotics, NHS, 11 Nov. 2022
- 6 Anderson, Leigh. “Antibiotics Guide.” Drugs.com, Drugs.com, 19 July 2023
- 7 News無綫新聞TVB. “專家指本港抗生素抗藥性高於其他先進國家.” 無綫新聞 TVB News, 無綫新聞TVB News, 2 Nov. 2016
- 8 Medical News Today. “Antibiotics: Uses, Resistance, and Side Effects.” Www.medicalnewstoday.com, 18 Dec. 2023
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