Antibiotics

Question 1

Why are amimoglycosides inactive against anaerobes and streptococci?

Answer 1

These bacteria do not contain an oxygen dependent transport system

Question 2

Name the aminoglycosides

Answer 2

Gentamcin, amikacin, neomycin and tobramycin

Question 3

What are the two major side effects with aminoglycosides?

Answer 3

Nephrotoxicity and ototoxicity

Question 4

What drugs increase the chance of ototoxicity when prescribed with aminoglycosides

Answer 4

Loop diuretics and vancomycin

Question 5

What drug(s) increases the chance of nephrotoxicity with aminoglycosides?

Answer 5

Ciclosporin, cephalosporins or vancomycin

Question 6

Why must you use ibw in dose obese patients with gentamycin?

Answer 6

As this drug is distributed in body water and doesn’t deposit in fat

Question 7

Name the carbapenems

Answer 7

Meropenem
Ertapenem
Impenem with cilastatin

Question 8

What activity do carbapenems have?

Answer 8

Broad against Gram +ve, -ve and anaerobes

Question 9

Which carbapenem has no activity against pseudomonas?

Answer 9

Ertapenem

Question 10

Why is cilastatin given with imipenem?

Answer 10

Because enzyme activity in the kidneys deactivates the imipenem. Cilastatin inhib these enzymes

Question 11

Carbapenems have a risk a seizures but one less so. Because if this it can be used for cns infections. Which one is this?

Answer 11

Meropenem

Question 12

What are the important side effects regarding carbapenems? (3)

Answer 12

Abx associated colitis
Hypersensitivity reaction
Numerological toxicity, like seizures

Question 13

How does carbapenems interact with warfarin?

Answer 13

Kills natural gut flora that produce vitamin K therefore enhancing warfains affect

Question 14

Are carbapenems reserved Abx for severe infections?

Answer 14

Yes

Question 15

How does carbapenems interact with valperate?

Answer 15

Reduces plasma conc and efficacy

Question 16

How many generations of cephalosporins are there?

Answer 16

5

Question 17

Name the glycopeptides

Answer 17

Dalbavancin
Teicoplanin
Telavancin
Vancomycin

Question 18

What are the major side effects of vancomycin?

Answer 18

Nephrotoxicity

Ototoxicity

Question 19

What happens (if anything) when vancomycin is given as a rapid infusion?

Answer 19

A anaphylactoid reaction can occur. Therefore must be given for at least an hour

Question 20

Name the macrolides?

Answer 20

Clarithromycin
Azithromycin
Erythromycin

Question 21

What interaction is there with macrolides and SSRIs?

Answer 21

Both can prolong QT interval

Question 22

What are the important side effect of carbapenems? (3)

Answer 22

Antibiotic induced colitis
Hypersensitivity
Risk of neurological toxicity

Question 23

What carbapenem can be given for a CNS infection and why?

Answer 23

Meropenem because they have a lesser seizure producing potential

Question 24

What major interactions do carabpenems have?

Answer 24

Warfarin - due to the effect of natural gut flora lowering levels of vitamin k
Valporate - as they reduce its plasma concentration and efficacy

Question 25

What are cephalosporins indicated for?

Answer 25

``` Septicaemia Pneumonia Meningitis Biliary tract infections Peritonitis UTIs ```

Question 26

Cephalosporins penitrate the cns poorly. So why are they indicated in meningitis?

Answer 26

Because in meningitis the meninges are inflamed so they're able to penitrate

Question 27

Give a brief description of 1st generation cephalosporins

Answer 27

This have a similar spectrum of activity as penicillin and are useful in respiratory infections, otis media, UTIs and skin/soft tissue infections

Question 28

In regards to cephalosporins. How does the 2nd generation differ from the 1st?

Answer 28

Has the same spectrum but is poorly absorbed so need to be taken with food

Question 29

In regards to cephalosporins how does the 3rd generation differ to previous generations?

Answer 29

Great spectrum of activity against gram -ve bacteria

Question 30

What generation of cephalosporins has the best spectrum of activity?

Answer 30

The fifth generation

Question 31

What is the target site for macrolides?

Answer 31

50s subunit in the ribosome

Question 32

What risk is there giving macrolides IV

Answer 32

Thrombophlebitis

Question 33

What affect can macrolides have on the liver?

Answer 33

Cholestatic jaundice

Question 34

What side effects can macrolides cause and which one causes them more frequently? (5)

Answer 34

1. GI disturbances, 2. throbophlebitis (when given IV), 3. C.Diff, cholestatic jaundice, 4. QT prolongation, 5. ototoxicity (at high doses)

Question 35

Are erythromycin and clarithromycin CYP450 inducers or inhibitors?

Answer 35

Inhibitors

Question 36

Why are macrolides so good for LRTI?

Answer 36

As they cover atypical penicillin resistant organisms

Question 37

Name the quinolones

Answer 37

``` Levofloxacin Ciprofloxacin Moxifloxacin Delafloxacin Ofloxacin ```

Question 38

Which quinolone has the greater activity?

Answer 38

Levofloxacin

Question 39

Which organism has a large prevalence of resistance to quinolones?

Answer 39

Streptococci

Question 40

What are the MRHA warning regarding quinolines?

Answer 40

1. They may indice convulsions in patients with or without a history 2. Tendon damage can occur 3. High risk of aortic aneurysms

Question 41

When should caution be taken when using quinolones? (6)

Answer 41

1. Cardiac conditions as can prolong QT intervals 2. Pts who have a pre disposition to seizures 3. Diabetes as can affect blood sugars 4. G6PD deficiency 5. Children as can cause arthopathy in weight baring joints 6. UV exposure

Question 42

Are quinolones bactericidal or bacteristatic? And what's their mechanism of action?

Answer 42

Bactericidal by inhibiting DNA synthesis

Question 43

With quinolone has activity against pseudomonas?

Answer 43

Ciprofloxacin

Question 44

What are the major side effects of quinolones? (3)

Answer 44

1. Low seizure threshold 2. Inflame and rupture tendons 3. Prolong QT interval

Question 45

What interactions must you be weary of in regards to quinolones?

Answer 45

Calcium and zinc as they reduce absorption NSAIDs due to effects of seizure threshold Prednisolone as they increase tendon rupture risk Any drug that prolongs the QT interval Also Ciprofloxacin inhibits some CYP450 enzymes so increases the concentration of theophylline

Question 46

Name the tetracyclines

Answer 46

``` Demeclocycline Doxycyline Lymecycline Minocycline Oxytetracycline Tetracycline Tigecycline ```

Question 47

What are the main indications for tetracyclines?

Answer 47

Chlamydia Acne LRTI

Question 48

Which tetracycline has the biggest spectrum of activity?

Answer 48

Minocycline

Question 49

What serious side effect is minocycline associated with?

Answer 49

It can cause lupus erythematosus like syndrome and irreversible pigmentation

Question 50

Why must you not give tetracyclines to pregnant and breast feeding women?

Answer 50

As they can affect the development of the babies bones

Question 51

What is the target site for tetracyclines?

Answer 51

The 30s ribosome subunit

Question 52

What are the 5 major side effects of tetracyclines?

Answer 52

Oesphagael irritation Photosensitivity Discolouration and/or hypoplasia of the teeth enamel in children Hepatotoxicity Intercraneal HTN (headaches and blurred vision)

Question 53

What are the interactions to be mindful of with tetracyclines?

Answer 53

Ca, antacids and ieon (chelating effect) | Enhance the affect of warfarin due to its effect on gut flora

Question 54

Why must you be mindful of renal function when giving tetracyclines?

Answer 54

They can increase urea and also when impaired tetracycline clearance is reduced

Question 55

What must you be mindful about when giving someone demeclocycline and syndrome of inappropriate ADH?

Answer 55

Demeclocycline can increase the patients sodium

Question 56

What is metronidazole used for?

Answer 56

Treating anaerobes and protozoa

Question 57

What is the mechanism of action of metronidazole?

Answer 57

When in an anaerobic bacteria they are reduced into nitroso free radicals interfering with FNA synthesis

Question 58

When is metronidazole not recommended in women?

Answer 58

During their menstruation

Question 59

What are the significant side effects of metronidazole?

Answer 59

GI upset With prolonged use can cause peripheral & optic neuropathy, seizures, encephalopathy and leucopenia

Question 60

What antibiotics can you not have alcohol with?

Answer 60

Metronidazole as it inhibits acetaldehyde dehydrogenase

Question 61

What are the most common Bacteria for a skin infection

Answer 61

Staph.Aureus Streptococci.Pyogenes Pusedomonus.A

Question 62

What are the common organisms associated with meningitis?

Answer 62

Streptococci pneumoniae Meningcocci H.Influenzea Listeria

Question 63

What organisms are commonly associated with eye infections?

Answer 63

Staph.Aureus Clamidyia Gonorrhea

Question 64

What organism is associated with ear infections ?

Answer 64

Streptococci pneumoniae

Question 65

What organisms are associated with URTI?

Answer 65

Strep.pyogenes | Haemophilia influenzae

Question 66

What is the organism associated with infections of the stomach?

Answer 66

H.pylori

Question 67

Name the anti psudomonal penicillins

Answer 67

Tazocin | Ticarcillin with clavulanic acid

Question 68

Name the broad spectrum penicillins

Answer 68

Amoxicillin Ampicillin Co-amoxiclav Co-fluampicil

Question 69

Name the beta lactamase sensitive penicillin

Answer 69

Benzylpenicillin | Phenoxylmethylpenicillin

Question 70

Name the penicillinase resistant penicillin

Answer 70

Flucloxacillin

Question 71

What is the interaction with penicillins and MTX?

Answer 71

Reduces the renal clearance

Question 72

What hepatic affects can Amoxcilin or co-amoxiclav cause?

Answer 72

Cholestatic or hepatitis