Week 2 Chapter 9

Chapter 9 Pharmacology Bullets: Antibiotics 💊🦠

Based on your Chapter 09: Antibiotics slides.

Big Idea for Pharmacology

• Antibiotics are medications that treat bacterial infections.

• Antibiotics work by either:

  • Killing bacteria directly

  • Stopping bacteria from growing or multiplying

• Antibiotics do not treat viral infections like:

  • Common cold

  • Most sore throats

  • Flu

  • Many sinus infections

Antibiotics: Basic Definition 💊

• Antibiotics are chemicals that inhibit specific bacteria.

• They can be made:

  • By living microorganisms

  • By synthetic manufacture

  • Through genetic engineering

Nursing Student Tip

• Think:
  Antibiotics = anti-bacteria medications.

Types of Antibiotics

Bacteriostatic 🛑

• Bacteriostatic antibiotics slow or stop bacterial growth.

• They do not directly kill the bacteria right away.

• They give the immune system time to fight the infection.

Easy Memory

• Static = stops growth

Bactericidal ☠

• Bactericidal antibiotics kill bacteria directly.

Easy Memory

• Cidal = kills

Bacteriostatic vs. Bactericidal

Signs of Infection 🚨

Common signs of infection include:

• Fever

• Lethargy

• Elevated white blood cell count

• Redness

• Swelling

• Heat

• Pain

Nursing Student Tip

• Classic inflammation signs are:
  Redness, swelling, heat, and pain.

Goal of Antibiotic Therapy 🎯

• The goal is to decrease the number of invading bacteria.

• Once the bacteria population is lower, the patient’s immune system can help finish fighting the infection.

Easy Way to Understand

• Antibiotics weaken the bacterial infection.

• The immune system helps clean up the rest.

Selecting Antibiotic Treatment

Culture 🧫

• A culture identifies the organism causing the infection.

Easy Memory

• Culture = what bacteria is growing?

Sensitivity Testing 💊

• Sensitivity testing tells which antibiotic will best kill or control the bacteria.

Easy Memory

• Sensitivity = what antibiotic works?

Culture and Sensitivity Together

• Culture tells the provider:
  “What bacteria is it?”

• Sensitivity tells the provider:
  “What drug will work best?”

Bacteria Classification 🦠

Gram-Positive Bacteria

• Gram-positive bacteria retain the stain.

• Their cell wall holds onto the stain.

Easy Memory

• Positive = keeps the stain.

Gram-Negative Bacteria

• Gram-negative bacteria lose the stain.

• Their cell wall is decolorized by alcohol.

Easy Memory

• Negative = loses the stain.

Aerobic Bacteria

• Aerobic bacteria need oxygen to survive.

Easy Memory

• Aerobic = air/oxygen.

Anaerobic Bacteria

• Anaerobic bacteria do not use oxygen.

Easy Memory

• Anaerobic = absence of oxygen.

Antibiotic Resistance 🦠💪

• Bacteria can adapt to their environment.

• The longer an antibiotic has been used, the greater the chance bacteria can become resistant.

• Antibiotic use can lead to:

  • Resistant strains

  • Superinfections

  • Overgrowth of resistant pathogens

Nursing Student Tip

• Resistance means the antibiotic does not work as well anymore.

Superinfection ⚠

• A superinfection happens when antibiotics kill normal bacteria, allowing other organisms to overgrow.

Examples

• Yeast infection

• C. difficile diarrhea

• Mouth sores

• New fever

• Vaginal itching or discharge

Nursing Alert

• Teach the patient to report:

  • Severe diarrhea

  • Bloody stools

  • New fever

  • White patches in mouth

  • Vaginal itching/discharge

Aminoglycosides 💊

Prototype Drugs

• Amikacin

• Gentamicin

• Neomycin

• Plazomicin

• Streptomycin

• Tobramycin

Action

• Aminoglycosides are bactericidal.

• They inhibit protein synthesis in bacteria.

• They bind to bacterial ribosomes.

• This causes incorrect reading of genetic code.

• The bacteria die.

Used For

• Serious infections caused mainly by aerobic gram-negative bacilli.

Pharmacokinetics

• Poorly absorbed from the GI tract.

• Rapidly absorbed after IM injection.

• Peak level occurs within about 1 hour after IM injection.

• Widely distributed in the body.

• Cross the placenta.

• Enter human milk.

• Excreted unchanged in the urine.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to aminoglycosides

• Renal disease

• Preexisting hearing loss

• Myasthenia gravis

• Parkinsonism

• Pregnancy

• Renal impairment

Major Adverse Effects

• CNS effects

• Kidney toxicity

• GI effects

• Cardiac effects

• Hypersensitivity reactions

Major Nursing Concerns

• Nephrotoxicity = kidney damage

• Ototoxicity = hearing damage

Nursing Student Tip

• Aminoglycosides are serious antibiotics with serious side effects.

• Monitor:

  • Kidney function

  • Hearing changes

  • Tinnitus

  • Balance problems

  • Urine output

Patient Teaching

• Drink plenty of fluids unless contraindicated.

• Maintain nutrition even if nausea, vomiting, or diarrhea occur.

• Report hearing changes or ringing in the ears.

• Report decreased urine output.

Carbapenems 💊

Prototype Drugs

• Doripenem

• Ertapenem

• Imipenem-cilastatin

• Imipenem-cilastatin-relebactam

• Meropenem

• Meropenem-vaborbactam

Action

• Carbapenems are bactericidal.

• They interfere with bacterial cell structure, leading to cell death.

Spectrum

• Broad-spectrum

• Effective against:

  • Gram-positive bacteria

  • Gram-negative bacteria

Used For

Serious infections such as:

• Intra-abdominal infections

• Urinary tract infections

• Skin infections

• Skin structure infections

• Bone and joint infections

• Gynecological infections

Pharmacokinetics

• Rapidly absorbed if given IM.

• Reach peak at end of infusion if given IV.

• Widely distributed in the body.

• Excreted unchanged in the urine.

• Average half-life is about 1 to 4 hours.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to carbapenems

• Allergy to beta-lactams

• Pregnancy

• Lactation

• Renal impairment

Adverse Effects

• GI effects

• Superinfections

• CNS effects

Drug Interactions

• Consider an alternative if patient takes valproic acid.

• Avoid concurrent use of imipenem with ganciclovir.

Nursing Student Tip

• Carbapenems are “big gun” antibiotics for serious infections.

• Watch for superinfection and kidney function issues.

Cephalosporins 💊

Prototype Drugs

First Generation

• Cefazolin

• Cefadroxil

• Cephalexin

Second Generation

• Cefaclor

• Cefotetan

• Cefoxitin

• Cefprozil

• Cefuroxime

Third Generation

• Cefdinir

• Cefotaxime

• Cefpodoxime

• Ceftazidime

• Ceftriaxone

Fourth and Other

• Cefepime

• Cefiderocol

• Ceftaroline

• Ceftazidime-avibactam

• Ceftolozane-tazobactam

Action

• Cephalosporins interfere with bacterial cell wall building.

• They can be bactericidal or bacteriostatic depending on the drug and dose.

Used For

• Infections caused by susceptible bacteria.

Pharmacokinetics

• Primarily excreted unchanged in urine.

• Some are eliminated by the liver.

• Cross the placenta.

• Enter human milk.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to cephalosporins

• Allergy to penicillins

• Hepatic impairment

• Renal impairment

• Pregnancy

• Lactation

Adverse Effects

• GI effects

• CNS symptoms

• Nephrotoxicity

• Superinfections

Drug Interactions

• Increased nephrotoxicity risk with aminoglycosides.

• Increased bleeding risk with warfarin.

Nursing Student Tip

• Always ask about penicillin allergy before giving a cephalosporin.

• Watch for:

  • Diarrhea

  • Rash

  • Superinfection

  • Kidney problems

  • Bleeding if on warfarin

Fluoroquinolones 💊

Prototype Drugs

• Ciprofloxacin

• Delafloxacin

• Levofloxacin

• Moxifloxacin

• Ofloxacin

Action

• Fluoroquinolones are bactericidal.

• They enter the bacterial cell by passive diffusion.

• They interfere with DNA enzymes.

• This causes bacterial cell death.

Used For

• Gram-positive bacterial infections

• Gram-negative bacterial infections

• Urinary tract infections

• Respiratory tract infections

• Skin infections

• Some are used for anthrax exposure treatment/prevention.

Pharmacokinetics

• Absorbed from the GI tract.

• Metabolized in the liver.

• Excreted in urine and feces.

• Widely distributed in the body.

• Cross the placenta.

• Enter human milk.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to fluoroquinolones

• Pregnancy

• Lactation

• Renal dysfunction

• Risk of cartilage damage

Serious Adverse Effects

• Tendinitis

• Tendon rupture

• Peripheral neuropathy

• CNS effects

• Prolonged QT interval

• C. difficile diarrhea

• Liver toxicity

Common Adverse Effects

• Headache

• Dizziness

• Insomnia

• Depression

• GI effects

• Immune reactions

Drug Interactions

Therapeutic effect can decrease with:

• Iron salts

• Sucralfate

• Multivitamins

• Calcium supplements

• Magnesium supplements

• Antacids

Use caution with:

• QT-prolonging drugs

• Warfarin

• NSAIDs

Nursing Student Tip

• Fluoroquinolones have important safety warnings.

• Teach the patient to report:

  • Tendon pain

  • Muscle weakness

  • Numbness or tingling

  • Severe diarrhea

  • Palpitations

  • Yellowing skin or eyes

Test Tip

• A contraindication is allergy to Cipro, because Cipro is a fluoroquinolone.

Penicillins 💊

Prototype Drugs

Natural Penicillins

• Penicillin G benzathine

• Penicillin G potassium

• Penicillin G procaine

• Penicillin V

Aminopenicillins

• Amoxicillin

• Ampicillin

Action

• Penicillins are bactericidal.

• They interfere with the bacteria’s ability to build cell walls.

Used For

• Streptococcal infections

• Pneumococcal infections

• Staphylococcal infections

• Other susceptible infections

Important Note

• Antipseudomonal penicillins have the widest spectrum.

Pharmacokinetics

• Rapidly absorbed from the GI tract.

• Excreted unchanged in the urine.

• Enter human milk.

Contraindications / Cautions

Use caution or avoid with:

• Penicillin allergy

• Allergy to other allergens

• Renal disease

• Pregnancy

• Lactation

Adverse Effects

• GI effects

• Superinfections

• Hypersensitivity reactions

Drug Interactions

• Parenteral aminoglycosides can interact with penicillins.

Nursing Student Tip

• Always ask:
  “Are you allergic to penicillin?”

• Watch for:

  • Rash

  • Hives

  • Swelling

  • Trouble breathing

  • Diarrhea

  • Superinfection

Sulfonamides 💊

Prototype Drugs

• Sulfadiazine

• Trimethoprim-sulfamethoxazole

  • Also called TMP-SMX

  • Brand names: Septra, Bactrim

Action

• Sulfonamides are bacteriostatic.

• They inhibit folic acid synthesis in bacteria.

• They block para-aminobenzoic acid, also called PABA.

Used For

• Gram-negative infections

• Gram-positive infections

• UTIs

• Trachoma

Pharmacokinetics

• Absorbed from the GI tract.

• Metabolized in the liver.

• Excreted in the urine.

• Distributed into human milk.

• Teratogenic.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to sulfonamides

• Allergy to thiazide diuretics

• Allergy to loop diuretics

• Pregnancy

• Lactation

• Renal disease

• History of kidney stones

• Older adults

Adverse Effects

• GI effects

• Renal effects

• CNS effects

• Bone marrow depression

• Dermatologic effects

Drug Interactions

Use caution with:

• Antidiabetic agents

• Drugs that increase hyperkalemia risk

• Cyclosporine

Nursing Student Tip

• Sulfonamides can increase the risk of kidney problems.

• Encourage fluids unless contraindicated.

• Monitor for rash.

• Report severe skin reactions immediately.

• Monitor CBC if ordered due to bone marrow depression risk.

Test Tip

• Sulfonamides should not be given with cyclosporine because the risk of nephrotoxicity increases.

Tetracyclines 💊

Prototype Drugs

• Tetracycline

• Demeclocycline

• Doxycycline

• Eravacycline

• Omadacycline

• Minocycline

• Sarecycline

Action

• Tetracyclines are bacteriostatic.

• They inhibit protein synthesis.

• This prevents bacteria from multiplying.

Used For

• Various infections caused by susceptible bacteria.

• Infections when penicillin is contraindicated.

Pharmacokinetics

• Absorbed from the GI tract.

• Concentrated in the liver.

• Excreted unchanged in the urine.

• Cross the placenta.

• Enter human milk.

Contraindications / Cautions

Avoid or use caution with:

• Allergy to tetracyclines

• Pregnancy

• Lactation

• Children younger than 8 years

Adverse Effects

• GI effects

• Skeletal effects

• Superinfections

• Local effects

Drug-Food / Drug-Drug Interactions

• Some oral combinations decrease absorption.

• Take on an empty stomach with water.

Nursing Student Tip

• Tetracyclines can affect bones and teeth.

• Avoid in young children and pregnancy unless specifically ordered.

• Teach the patient to take with water.

• Watch for GI upset and superinfection.

Antimycobacterials 💊

Used For

• Tuberculosis, also called TB

• Leprosy

TB First-Line Drugs

• Isoniazid

• Rifampin

• Pyrazinamide

• Ethambutol

• Rifabutin

• Rifapentine

Leprosy Drug

• Dapsone

Action

• Most act on bacterial DNA.

• This prevents growth and eventually causes bacterial death.

Pharmacokinetics

• Generally well absorbed from the GI tract.

• Metabolized in the liver.

• Excreted in the urine.

• Cross the placenta.

• Enter human milk.

Contraindications / Cautions

Use caution or avoid with:

• Allergy to these agents

• Severe renal failure

• Severe hepatic failure

• Pregnancy

Adverse Effects

• CNS effects

• GI irritation

• Hepatotoxicity risk with certain combinations

• Histamine reactions

Nursing Student Tip

• TB treatment usually requires multiple medications.

• Teach the patient not to stop treatment early.

• Monitor liver function.

• Watch for signs of liver problems:

  • Yellow skin

  • Yellow eyes

  • Dark urine

  • Right upper quadrant pain

  • Severe fatigue

Test Tip

• For TB, the provider may prescribe isoniazid.

Other Antibiotic Classes

Lincosamides

• Example:

  • Clindamycin

  • Lincomycin

• Usually bacteriostatic.

Lipoglycopeptides

• Examples:

  • Telavancin

  • Dalbavancin

  • Oritavancin

  • Vancomycin

• Usually bactericidal.

Macrolides

• Examples:

  • Erythromycin

  • Azithromycin

  • Clarithromycin

  • Fidaxomicin

• Can be bactericidal or bacteriostatic.

Oxazolidinones

• Examples:

  • Tedizolid

  • Linezolid

Monobactam

• Example:

  • Aztreonam

• Bactericidal

Miscellaneous Antibiotics

• Daptomycin

• Tigecycline

• Streptogramins

• Rifaximin

High-Yield Nursing Responsibilities 🩺

Before Giving Antibiotics

• Check allergies.

• Check culture and sensitivity results if ordered.

• Assess signs of infection.

• Check temperature.

• Check WBC count.

• Review renal function.

• Review liver function.

• Check pregnancy/lactation status if applicable.

• Review current medications for interactions.

During Antibiotic Therapy

• Monitor for improvement in infection.

• Monitor for allergic reaction.

• Monitor for GI upset.

• Watch for superinfection.

• Watch for kidney toxicity.

• Watch for liver toxicity.

• Teach the patient to finish the full prescription.

After Antibiotic Therapy

• Reassess infection symptoms.

• Monitor for recurring infection.

• Reinforce prevention teaching.

• Teach the patient not to save or share antibiotics.

Big Safety Alerts 🚨

• Aminoglycosides → nephrotoxicity and ototoxicity.

• Cephalosporins → ask about penicillin allergy.

• Fluoroquinolones → tendon rupture, QT prolongation, C. difficile, neuropathy.

• Sulfonamides → renal effects, rash, bone marrow depression.

• Tetracyclines → avoid in pregnancy and children under 8.

• Antimycobacterials → monitor liver function.

• All antibiotics → watch for superinfection and allergic reaction.

Quick Cram Sheet 📝

• Antibiotics treat bacterial infections.

• Bacteriostatic = stops/slows bacteria growth.

• Bactericidal = kills bacteria.

• Culture = identifies the bacteria.

• Sensitivity = tells which antibiotic works.

• Gram-positive = keeps stain.

• Gram-negative = loses stain.

• Aerobic = needs oxygen.

• Anaerobic = does not need oxygen.

• Resistance = bacteria adapts and drug works less.

• Superinfection = new infection from disrupted normal flora.

• Aminoglycosides = serious gram-negative infections; kidney and hearing toxicity.

• Carbapenems = broad-spectrum “big gun” antibiotics.

• Cephalosporins = cell wall drugs; watch penicillin allergy.

• Fluoroquinolones = DNA enzyme drugs; tendon rupture risk.

• Penicillins = cell wall drugs; ask allergy first.

• Sulfonamides = folic acid blockers; watch kidney and rash.

• Tetracyclines = protein synthesis blockers; avoid pregnancy and kids under 8.

• Antimycobacterials = TB and leprosy drugs; monitor liver function.

• Always teach patients to finish the full course.