General Principles of Anti-Infectives

Anti-infectives

Anti-infectives are medicines used to prevent or treat infections caused by microorganisms like bacteria, viruses, fungi, or parasites. They work by either:Killing the organisms (bactericidal or fungicidal), orStopping their growth or reproduction (bacteriostatic or fungistatic). 

Antibacterials

1. Aminoglycosides

2. Cephalosporins

3. Lincosamides

4. Macrolides

5. Penicillins

6. Quinolones

7. Tetracyclines

8. Other antibacterials

Types of Anti-Infectives: 

Antibiotics – treat bacterial infections (e.g. amoxicillin, ciprofloxacin)

Antivirals – treat viral infections (e.g. acyclovir for herpes, oseltamivir for flu)

Antifungals – treat fungal infections (e.g. fluconazole for thrush)

Antiparasitics – treat parasitic infections (e.g. albendazole for worms) 

In simple terms, anti-infectives are the medicines that help the body fight off germs. Pharmacists use them carefully to make sure the treatment works and doesn’t cause unnecessary resistance or harm.

1. Why This Matters

• Anti-infectives (like antibiotics and antifungals) are commonly used in retail pharmacy

• Misuse can lead to treatment failure, side effects, and antibiotic resistance

• As an intern, your role in safe dispensing and patient education is critical

2. Choosing the Right Medicine

• Always choose the safest, most targeted treatment.

• Narrow-spectrum antibiotics are preferred (they target specific bacteria and cause fewer side effects)

• Base your choice on:

  • What bacteria is most likely causing the infection

  • Where the infection is (e.g. skin, lungs, urinary tract)

  • How sick the patient is

  • How safe, effective, and affordable the drug is

⚠️ Never use antibiotics for viral infections like colds or the flu.

3. When to Use Anti-Infectives

Only use antibiotics when clearly needed.

•  Some infections get better on their own (e.g. mild colds, most sore throats)

• If you can, take a swab or culture before starting antibiotics to confirm the bacteria

• Broad-spectrum antibiotics are NOT stronger—they just kill more types of bacteria, including good ones

  
  

Q4: Empirical Treatment

• 

  Sometimes you start treatment before knowing the exact bug.

• This is called empirical treatment

• Base your guess on:

  • Local resistance patterns (some bacteria are more resistant in certain areas)

  • The patient's history, symptoms, and risk of complications

• Only go broad if necessary

  
  

  
  

5: Using Antibiotics to Prevent Infection

• Use with clear medical reasons—never casually.

  Common reasons:

  • Certain surgeries (especially heart or bone implants)

  • Exposure to diseases like meningitis or TB

  • People with long-term medical risk (e.g. HIV, no spleen, frequent UTIs)

  • Surgical prophylaxis:

  • One antibiotic dose is usually enough before surgery

  • Repeat dose only if surgery is long or has blood loss

6: Combination Therapy

• Use more than one anti-infective only if needed, such as:

  • Infections caused by multiple organisms (e.g. diabetic foot infections)

  • When two drugs work better together (e.g. penicillin + gentamicin for endocarditis)

  • To stop bacteria from becoming resistant (e.g. TB treatment)

7: How Long Should Antibiotics Be Taken?

• Shorter courses are usually better.

  • Stop treatment once symptoms go away and lab tests are normal (unless told otherwise)

  • Examples:

  • Single dose: vaginal thrush, giardia, gonorrhoea

  • Short (<5 days): UTI, gastro

  • Standard (5–10 days): pneumonia, skin infections

  • Extended (>10 days): TB, endocarditis, bone infection

⚠️ 8: Side Effects and Risks

• More coverage = more side effects

  • Broad-spectrum antibiotics can:

    • Upset the gut (nausea, diarrhoea)

    • Cause yeast infections

    • Lead to dangerous superinfections like C. difficile

      
      

  • ➡️ Always explain these risks to the patient when counselling

9: Resistance – The Silent Crisis

• Every time an antibiotic is used, bacteria get a little smarter.

  • Don’t use antibiotics unless absolutely needed

  • Save strong drugs (like meropenem or vancomycin) for life-threatening cases

  • If resistance grows, we may run out of treatment options

    
    

10: Be Careful with Topical Antibiotics

• Avoid using creams or ointments unless truly necessary.

  • Risk of causing skin allergy or promoting resistance

  • Safe topical uses include:

    • Eye infections

    • Mupirocin (for nasal staph)

    • Chlorhexidine/povidone-iodine (for skin antisepsis)

11: Probiotics – Are They Useful?

• 

  Sometimes—but not always.

  • Live bacteria or yeasts (in yoghurt or supplements)

  • Claimed to improve gut health, but:

    • No strong evidence for preventing antibiotic diarrhoea or C. difficile

    • Different strains work differently (not all probiotics are the same)

  ⚠️ Avoid in very sick or immunocompromised people—they could cause serious infection

12: What Should You Tell Patients?

Here’s a simple way to explain probiotics:

• “Probiotics may help with gut health, but they’re not guaranteed to work for everyone. They don’t prevent all antibiotic side effects, and they’re not safe for everyone—especially people with weak immune systems.”

📚 13: Auxe Tips

✔️ Use narrow-spectrum antibiotics whenever possible

✔️ Only treat infections that really need antibiotics

✔️ Shorter treatments are often safer and just as effective

✔️ Avoid broad-spectrum drugs unless clearly indicated

✔️ Counsel patients about resistance and side effects

✔️ Be cautious with probiotics—individualised use only