all aboard the antibiotic express

All Aboard the Antibiotic Express

With Shraya Pandya

Learning Objectives/Outcomes 1. To be able to list sites of antibiotics with examples

2. To recognize specific groups of antibiotics including:Beta LactamsGlycopeptides

AminoglycosidesMacrolides

Fluoroquinolones3. To give examples of antibiotic side - effects and interactions

Pharmacology: Antibiotics

Contents

Key Terms Sites of Action Specific Groups In Practice

Key TermsBactericidal:

Kill the bacteria.

Bacteriostatic:

Prevent bacteria from multiplying.

Key Terms

Sites of Action

Sites of Antibiotic

Action

Sites of Antibiotic Action• Cell Wall Synthesis• Cell Membrane• 30s Protein Synthesis• 50s Protein Synthesis• DNA• DNA Gyrase• Folic Acid Synthesis

Sites of Action

Sites of Antibiotic ActionSites of Action

Cell MembranePolymixins

Cell Wall SynthesisPenicillinsVancomycinCepahlosporinsCarbapenems

30s Protein SynthesisTetracyclinesStreptomycin (Aminoglycosides)Gentamicin (Aminoglycosides)

50s Protein SynthesisErythromycin (Macrolides)Clindamycin (Lincosamides)

DNANitrofurantoin (Macrobids)Metronidazole

DNA GyraseCiprofloxacin, Levofloxacin

Folic Acid SynthesisTrimethoprimSulfamethoxazole

Specific Groups

Specific GroupsLet’s Go Over…

Beta LactamsGlycopeptides

AminoglycosidesMacrolides

Fluoroquinolones

Inhibiting Cell Wall SynthesisBETA LACTAMS: PENICILLINS

Action: Bactericidal

Examples: Amoxicillin, Flucloxacillin, Piperacillin, Benzyl Penicillin

Uses: Broad - SpectrumBecomes more efficacious with Beta - Lactamase Inhibitors (Clavulanic Acid, Tazobactam) which will inhibit the bacterial breakdown of penicillin

Side Effects: Allergic Reactions - Immediate IgE mediated Anaphylaxis, Cholestasis (Flucloxacillin + Co-Amox), Rash with mononucleosis (Amoxicillin), Thrombocytopaenia

Interactions: Allopurinol + Methotrexate

Specific Groups

Inhibiting Cell Wall SynthesisBETA LACTAMS: CEPHALOSPORINS


Examples: Cefuroxime, Cefotaxime, Ceftriaxone

Uses: Cover Gram + and -, Pneumonia, Serious Intra abdominal infections and UTIs

Side Effects: Nephrotoxicity, Diarrhoea, Risk of C. difficile infection, Pseudocholelithiasis(ceftriaxone)

Specific Groups

Inhibiting Cell Wall SynthesisBETA LACTAMS: CARBAPENEMS


Examples: Meropenem, Imipenem

Uses: Gram + and - + Anti-Pseudomonal/Anaerobes

Side Effects: Nephrotoxicity at high concentrations, Rash, Seizures

Specific Groups

Inhibiting Cell Wall SynthesisGLYCOPEPTIDES


Examples: Vancomycin, Teicoplanin

Uses: Against MRSA, C. difficile (hospital acquired)

Side Effects: Nephrotoxicity, Skin rashes, Red Man Syndrome (Vancomycin)

Specific Groups

Inhibiting Protein Synthesis: 30sAMINOGLYCOSIDES


Examples: Gentamicin, Streptomycin, Amikacin

Uses: Gram +, Systemic Sepsis

Side Effects: Ototoxicity (Gentamicin), Nephrotoxicity

Interactions: Increased nephrotoxicity with vancomycin, CI in Myasthenia Gravis (Gentamicin)

Specific Groups

Inhibiting Protein Synthesis: 30sTETRACYCLINES

Action: Bacteriostatic

Examples: Tetracycline, Doxycycline

Uses: Gram +, Renal Impairments as an alternative to B-lactams

Side Effects: Loss of appetite, GI Upset/ AAD, Sore throat, Photosensitivity

Specific Groups

Inhibiting Protein Synthesis: 50sMACROLIDES

Action: Bacteriostatic + Bactericidal

Examples: Clarithromycin, Azithromycin, Erythromycin

Uses: Gram + , STIs, RTI, Otitis Media

Side Effects: QT prolongation, GI disturbance, Hypersensitivity, Skin rashes, Cholestatic Jaundice, Tinnitus (Azithromycin)

Interactions: StatinsSpecific Groups

Inhibiting Protein Synthesis: 50sLINCOSAMIDES

Action: Bacteriostatic + Bactericidal

Examples: Clindamycin, Lincomycin

Uses: Prophylaxis for Infective Endocarditis in Penicillin Allergy, Osteomyelitis

Side Effects: Skin rash, Diarrhoea,

Specific Groups

DNA GyraseFLUOROQUINOLONES


Inhibit Topoisomerase II (DNA Gyrase) and IVExamples: Ciprofloxacin, Levofloxacin

Uses: Gram - (GI/UTI), Anti-Pseudonomal, Opthalmic uses, TB

Side Effects: Tendonitis / rupture , AAD, Prolonged QT, Lowers seizure threshold, Photosensitivity (Ciprofloxacin)

Interactions: Avoid in pregnancy + G6PD

Specific Groups

Folic Acid SynthesisSULPHONAMIDES


PABA to DHFA blocked

Side Effects: Hypersensitivity, Skin rash, Headaches, PhotosensitivityThrombocytopaenia

Usually used in combination with trimethoprim

Specific Groups

Folic Acid SynthesisTRIMETHOPRIM


DHFA to THFA Blocked

Uses: In combination with sulphonamide (co-trimoxazole), RTI (Pneumonia), UTI

Side Effects: CI in patients with Megaloblastic Anaemia (Folate Deficiency), Pruritus, Suppression of hematopoiesis, Photosensitivity

Specific Groups

DNA MACROBIDS


Examples: Nitrofurantoin

Uses: Often used for UTIs, Against G -

Side Effects: Peripheral Neuropathy, GI Upset, Lung Fibrosis (Long term use)

Specific Groups

DNA SynthesisMETRONIDAZOLE


Reduction of metronidazole into active form in anaerobes only.

Uses: Treat C- Difficile

Side Effects: Metallic Taste, Intolerance to Alcohol

Specific Groups

In Practice:Tips + Tricks

In Practice

Antibiotic Coverage

So here’s one way to learn them…Many charts like this are available.Here’s one from Zero to Finals

But if this seems overwhelming to you… check out the next slide

Antibiotics in Practice

Wheel of Common Antibiotics in Practice



Wheel of Abx

There’s no perfect way…Find what works for you!

• Make your own mnemonics• Draw and Write• YouTube!• See it in practice!


Summary1 2 3

Lesson Recap 1Various sites of action to

inhibit bacteria:

• Cell Wall Synthesis

• 30s/ 50s Protein

Synthesis

• DNA

Lesson Recap 2Remember the main uses + side effects as its high yield

information for your exams!

Lesson Recap 3Think about what you see

at your local trusts and put your knowledge into

practice!

Additional Resources

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all aboard the antibiotic express

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