Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Applied Pharmacology > Antibiotics > Flashcards

Antibiotics Flashcards

1
Q

Penicillin - Example

A
  • benzylpenicillin

- phenoxymethylpenicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Penicillin - Indication

A
  1. Streptococcal Infections: tonsilitis, pneumonia, endocarditiis , skin/soft tissue infections
  2. Meningococcal infection: meningitis and septicaemia
  3. Clostridial infection such as tetanus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is penicillin narrow or broad spectrum?

A

Narrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Penicillin - MOA

A

Penicillin act by inhibiting the peptidoglycans in the bacterial cell wall which weakens the cell walls. They cannot maintain an osmotic gradient and this leads to uncontrolled entry of water. The cells begin to swell and eventually lysing and dying.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What gives Penicillin it’s antibiotic properties?

A

Penicillin contains a B-lactam ring which is responsible for their bacteriacidal activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do side chains on B-lactam ring do?

A

The side chains can be linked to the B-lactam ring and influence the nature of the antibiotic determining the antibacterial spectrum and other properties of the drug.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do bacteria resist Penicillin?

A

bacteria resist the action of penicillin by synthesising B-lactamases which break down the B-lactam ring and thus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are side effects of Penicillin?

A
  1. Penicillin allergy = presents as a skin rash 7-10 days after first exposure and 1-2days after repeat exposure
  2. Less common : anaphylactic reaction- Characterised by hypotension, bronchial and laryngeal spasm/oedema and angioedema.
  3. Central nervous system toxicity which usually happens in high doses of penicillin or where severe renal impairment delays excretion = pt usually has convulusions or coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the contraindications of Penicillin?

A
  1. a history of penicillin allergy

2. renal impairment - reduced dose required because other can lead to a delay in excretion leading to toxicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the interactions of Penicillin?

A

reduces renal excretion of methotrexate increasing the risk of toxicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Broad spectrum penicillin - Examples

A

Amoxicillin and co-amoxiclav.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Broad spectrum penicillin - Indication

A
  1. Susceptible infections such as
    - community acquired pneumonia
    - otitis media
    - UTIs
    - sinusitis
  2. H.Pylori associated peptic ulcers
  3. Severe-resistant hospital acquired infections - usually co-amoxiclav
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Broad spectrum penicillin- MOA

How does it differ to other kinds of penicillin?

A

Some MOA of weakening bacterial cell wall leading to cell swelling and lysis of the bacteria. Bactericidal properties brought about by the B-lactam ring.

They way it differs is that it’s synthesised with additional amino group to the B-lactam ring side chain ehich broadens the activity against aerobic Gram negative bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Broad spectrum penicillins - Side Effects

A
  1. GI upset including nausea and diarrhoea
  2. penicillin allergy which usually presents as a skin rash or can lead to delayed or immediate IgE-mediated anaphylactic reaction
  3. Acute liver injury/jaundice or hepatitis may develop during or shortly after co-amoxiclav and is usually self-limiting once the Tx is stopped.
  4. less commonly antibiotic-associated colitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Broad spectrum penicillins - Contraindication

A
  1. History of allergy
  2. pt in risk of C.difficile infection - hospitalised pts and elderly
  3. penicillin associated liver injury
  4. severe renal impairment - dose should be reduced (risk of crystalluria)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Broad spectrum penicillins - Interaction

A

They can enhance to anticoagulant effect of warfarin by killing normal gut flora that synthesise vitamin K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Macrolides - Examples

A
  • clarithromycin
  • erythromycin
  • azithromycin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Macrolides - Indications

A
  1. Respiratory, skin and soft tissue infections = usually as an alternative to penicillin
  2. Severe pneumonia - added to penicillin to cover atypical pathogens such as legionella pneumophila and mycoplasma pneumoniae.
  3. H.Pylori eradication Tx in combination with PPI and either amoxicillin and metronidazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Macrolides - Spectrum of activity

A

erythromycin is relatively broad spectrum active against gram-positive and some gram-negative pathogens

synthetic macrolides such as clarithromycin and azithromycin have increased activity against gram-negative pathogens particularly haemophilus influenzae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Macrolides - MOA

Type of Abx

A

Macrolides inhibit bacterial protein synthesis. They do this by binding to the 50S subunit of the bacterial ribosome blocking translocation (needed to elongate polypeptide/protein).

it is a bacteriostatic antibiotic = prevents the growth/multiplication of bacteria thus providing the immune system with more time to kill and remove bacteria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Macrolide - Side Effects

A

most common and severe in eythromycin

side effects:
1. irritant causing nausea, vomiting, abdo pain and diarrhoea and also thrombophlebitis when given via IV.

  1. allergy
  2. antibiotic associated coiltis
  3. liver abnormalities such as cholestatic jaundice
  4. prolongation of QT interval thus predisposing arrythmias
  5. ototoxicity at high doses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Macrolide - Contraindication /Caution

A
  1. History of hypersensitivity/allergy
  2. severe hepatic impairment
  3. severe renal impairment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Macrolide - Interaction

A
  • Macrolide inhibit CYP enzymes : increases conc of drugs metabolised by them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Tetracycline - Examples

A
  • doxycycline

- lymecycline

25
Q

Tetracycline - Indication

A
  1. Acne Vulgaris = presence of inflamed papules, pustules and/or cysts
  2. Lower respiratory Tract infections (LRTI) = includes infective exacerbations of COPD, pneumonia and atypical pneumonia
  3. Chlamydial infection = includes pelvic inflammatory disease
  4. Other infections = typhoid, anthrax, malaria and Lyme disease
26
Q

Tetracycline - MOA

A
  • Tetracycline inhibit the bacterial protein synthesis.
  • They bind to the 30S subunit found specifically in bacteria preventing transcription & translation.
  • They are therefore deemed as bacteriostatic antibiotics.
27
Q

Tetracycline - Spectrum of activity

A

Tetracyclines are relatively broad spectrum active against many gram-positive and gram-negative bacteria including chlamydia, mycoplasma and spirochaetes. However, their utility is limited by increase if resistance.

28
Q

Tetracycline - Side Effects

A

Most commonly causes by nausea, vomiting and diarrhoea. (slightly lower risk of coilitis)
Hypersensitivity reactions occur which can be either immediate or delayed.

tetracycline specific:
1. oesophageal irritation, ulceration and dysphagia

  1. photosensitivity and discolouration of skin and/or hypoplasia of tooth enamel
  2. Less common: hepatotoxicity and intracranial hypertension (leading to headaches and visual disturbance)
29
Q

Tetracycline - Contraindications

A

Avoid use in infancy/childhood (under 12yrs) because it can have an effect on teach and bone during development
for this reason should not be given in pregnancy or breastfeeding

30
Q

Tetracycline - Caution

A
  • renal impairment as anabolic effect raises serum urea and reduced excretion = more risk of adverse effects.
31
Q

Tetracycline - Interactions

A

tetracyclines bind to divalent cations and therefore shouldn’t be given within 2 hours of calcium, antacids or iron preventing antibiotic absorption.

Tetracyclines enhance the anticoagulant effect of warfarin killing gut bacteria which synthesise vit K.

32
Q

Trimethoprim - Indications

A
  1. Uncomplicated UTI = alternatives include Nitrofurantoin and amoxicillin.
  2. Prophylaxis of recurrent UTI.

also Tx option for:

  • acne
  • respiratory tract infections
  • Pneumocystis pneumonia in immunocompromised pt = co-trimoxazole
33
Q

Trimethoprim - MOA

A

trimethoprim inhibits bacterial folate synthesis.
folate is needed for essential functions such as DNA synthesis and it must be their own folate

therefore, this slows down bacterial growth = bacteriostasis

34
Q

Trimethoprim - Side Effects

A
  1. GI upset (nausea, vomiting and sore mouth)
  2. skin rash
  3. more rare but can cause hypersenstivity recations including anaphylaxis, drug fever and erythema multiform.
  4. can impair haematopoiesis causing haematological disorders e.g. megaloblastic anaemia, leucopenia and thrombocytopenia.
  5. hyperkalaemia and elevated plasma creatinine
35
Q

Trimethoprim - Contraindications

A

First trimester of pregnancy, because folate antagonist is associated with increased risk of fetal abnormalities.

36
Q

Trimethoprim - Caution

A
  • folate deficiency - more susceptible to haematological effects.
  • renal impairment - excreted by the kidneys and so reduced dose is used.
  • neonates, elderly, and HIV patients
37
Q

Trimethoprim - Interactions

A
  • potassium-elevating drugs (aldosterone antagonists, ACEi, ARBs) predisposes to hyperkalaemia
  • use with other folate antagonists (methotrexate) and drugs that increase folate metabolism (Phenytoin) increases the risk of adverse haematological effects
  • Trimethoprim can enhance the anticoagulant effect of warfarin by killing normal gut flora that synthesis Vit K.
38
Q

Trimethoprim - Spectrum of activity

A

Broad spectrum

39
Q

Nitrofurantoin - Indications

A
  1. acute uncomplicated LUTI (alternatives are trimethoprim, amxocillin and cefelaxin)
  2. Prophylaxis of reccurent UTI.
40
Q

Nitrofurantoin - MOA

A

Free Radicals

  • Nitrofurantoin is metabolised (reduced) in bacterial cells by nitrofuran reductase.
  • Its active metabolite damages bacterial DNA and causes cell death (bactericidal).
41
Q

Nitrofurantoin - Side Effects

A
  1. GI upset (nausea and diarrhoea)
  2. immediate and delayed hypersensitivity reactions
  3. dark yellow/brown coloured urine

less common

  1. chronic pulmonary recations (pneumonitis and fibrosis)
  2. hepatitis
  3. peripheral neuropathy

neonates = haemolytic anaemia - immature RBCs can’t mop up superoxides formed by nitrofurantoin damaging the RBCs.

42
Q

Nitrofurantoin - Contraindications

A
  1. pregnant women towards term or babies in the first 3 months of life
  2. renal impairment - impaired excretion increases risk of toxicity and lower drug conc reduces efficacy
43
Q

Nitrofurantoin - Caution

A

Chronic use in prophylaxis increases risk of adverse effect esp in elderly,

44
Q

Nitrofurantoin - Interactions

A

None

45
Q

Flucloxacillin - Class of druh

A

Penicillin, penicillin-resistant

46
Q

Flucloxacillin - Indications

A

Usually used in combined Tx for a staphylococcal infection

  1. skin and soft tissue infections = e.g. cellulitis (usually combined with benzylpenicillin)
  2. Osteomyelitis and septic arthritis
  3. Other infections including endocarditis
47
Q

Flucloxacillin - MOA

A

Follow the similar MOA through targeting the peptidoglycan in bacterial cell walls.
Side chains an acyl side chain protects the B-lactam ring from B-lactamases making the antibiotic more effective agaisnt B-lactamse-producing staphylococci.

48
Q

Flucloxacillin - Spectrum of Activitiy

A

Narrow spectrum against Gram-positive staphylococci.

49
Q

Flucloxacillin - Side Effects

A
  1. Minor GI upset
  2. penicillin allergy - usually presents as a skin rash
  3. life-threatening anaphylactoid reaction
  4. Liver toxicity - including cholestasis and hepatitis (can occur up to 2months after Tx is completed)
50
Q

Flucloxacillin - Contraindications

A
  1. xhistory of penicillin allergy
  2. renal failure - reduced dose
  3. xprior flucloxacillin-related hepatotoxicity
  4. use with caution with hepatic impairment
51
Q

Flucloxacillin - Interactions

A

reduces renal excretion of methotrexate which increases the risk of toxicity.

52
Q

Vancomycin - Indication

A

1) Gram- positive infection (endocarditis)

2) Abx- associated colitis caused by C.diff

53
Q

Vancomycin - Spectrum of acitvity

A

Narrow

54
Q

Vancomycin - MOA

A

Vancomycin inhibits growth and cross-linking of peptidoglycan chains, inhibiting synthesis of the cell wall of Gram-positive bacteria, thus lysing and killing the bacteria (bactericidal).

55
Q

Vancomycin - Side Effects

A

Most common:
- thrombophlebitis

Severe:
- ‘red man syndrome’ : erythema, hypotension, bronchospasm

Allergy

IV:
- nephrotoxicity, ototoxicity , thrombocytopenia

56
Q

Vancomycin - Contraindications

A

NONE

57
Q

Vancomycin - Caution

A

Renal impairment & elderly

58
Q

Vancomycin - Interactions

A
  • Increase otoxicity & nephrotoxicity with aminophycoside, loop diuretic, ciclosporin

Applied Pharmacology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions