AM - Side effects/toxicity

Question 1

What antimicrobial type most commonly causes allergic reactions?

Answer 1

B-Lactams

Question 2

How common is penicillin hypersensitivity?

Answer 2

True penicillin hypersensitivity is rare but alot of patients with other side effects are wrongly labelled as allergic

Question 3

Are penicillin alleric patients allergic to any other antimicrobials?

Answer 3

Around 10% of the truly penicillin alleric patients are also alleric to cephalosporins

Question 4

What are the 2 types of antimicrobial allergy?

Answer 4

Immediate hypersensitivity
Delayed Hypersensitivity

Question 5

Whats the most extreme form of immediate hypersensitivity?

Answer 5

Anaphylactic shock usually following parenteral administration of an antibiotic

Question 6

What mediates immmediate allergic reactions?

Answer 6

IgE

Question 7

What are the symptoms of immediate hypersensitivity?

Answer 7

• Itching
• Urticaria
• Nausea
• Vomiting
• Wheezing
• Shock
• Laryngeal Oedema

Question 8

What symptom of immediate hypersensitivity is most commonly fatal?

Answer 8

The laryngeal Oedema is often fatal if the airway isnt cleared.

Question 9

How long does a delayed hypersensitivity reactions take?

Answer 9

Hours or Days to occur

Question 10

What mediates delayed hypersensitivity reactions?

Answer 10

• Immune complexes
• or Cell mediated

Question 11

What are the symptoms of delayed hypersensitivity?

Answer 11

Drug rashes
Drug Fever
Serum Sickness
Erythema Nodosum

Question 12

Whats erythema nodosum?

Answer 12

Red lumps on the skin

Question 13

Describe the rashes in a delayed hypersensitivity reaction?

Answer 13

Rashes are maculopapular
i.e. flat red area of skin covered in small bumps

Question 14

Whats stevens-johnson syndrome?

Answer 14

A form of delayed hypersensitivity where the skin & mucous membranes are both involved.
Its associated with sulphonamides

Question 15

Whats the common gastrointestinal side effects of antimicrobials?

Answer 15

Nausea
Vomiting

Question 16

What is CDAD?

Answer 16

Clostridium Difficile Associated Diarrhoea

Question 17

Whats CDI?

Answer 17

Clostridium Difficile Infection (specifically infection of a dangerous strain no the normal commensal in the gut)

Question 18

Whats an EIA?

Answer 18

An Enzyme Immunoassay

Question 19

What happens to C. Diff. when during antibiotic use?

Answer 19

It overgrows normal flora in the gut and produces toxins

Question 20

What does C. Diff growth cause during antibiotic use?

Answer 20

Anything from mild CDAD or CDI to life threatening pseudomembranous colitis.

Question 21

How do we check fo a CDI?

Answer 21

Use an EIA to check the stool for toxins

Question 22

How do we treat a CDI?

Answer 22

Oral Vancomycin or metronidazole
IF possible stop all other antibiotic treatment

Question 23

How do we stop spores of the dangerous C Diff strains spreading?

Answer 23

• Isolating patients with CDI
• Hand Washing with soap (resistant to alcohol gel)

Question 24

What antimicrobials cause thrush?

Answer 24

Broad Spectrum penicillins & cephalosporins

Question 25

What is Thrush?

Answer 25

ORal and/or Vaginal Candidiasis (fungal infection of candida yeast)

Question 26

How do antimicrobials cause thrush?

Answer 26

Certain antimicrobials cause thrush by suppressing normal flora leading to overgrowth of yeast candida albicans

Question 27

What kind of liver toxicity can be caused by antimicrobials?

Answer 27

Varies from transient elevation of liver enzymes al the way to severe hepatitis

Question 28

In what patients are liver toxicity side effects most common?

Answer 28

Pregnant patients Or those with pre-existing liver disease

Question 29

Name some drugs associated with liver toxicicity:

Answer 29

Tetracycline Rifampicin Flucloxacillin Isoniazid (anti-TB)

Question 30

Who does nephrotoxiicty effect most?

Answer 30

People with pre-exisiting renal disease

Question 31

Why do we monitor the levels of aminoglycosides & vancomycin in the blood?

Answer 31

Because they can cause renal toxicity

Question 32

What drugs cause ototoxicity?

Answer 32

Aminoglycosides Vancomycin

Question 33

What drug can cause optic nerve damage?

Answer 33

Ethambutol an anti-TB drug can damage the optic nerve

Question 34

What do we monitor during ethambutol treatment?

Answer 34

Durin ethambutol treatment we monitor optic nerve function

Question 35

What drugs cause encephalopathy & convulsions?

Answer 35

High dose Penicillin High dose Cephalosporin Acyclovir (an anti-viral)

Question 36

How do we alter the drug if the pateint has renal impairment?

Answer 36

MAy have to reduce the dose proportionally to impairment to avoid toxicity (particularly encephalopathy & convulsion)

Question 37

What drugs can cause peripheral neuropathy?

Answer 37

Metronidazole Nitrofurantoin

Question 38

How does Isoniazid cause peripheral neuropathy?

Answer 38

By competetive inhibition wiht pyridoxine (Vitamin B6)

Question 39

In what ways can AMs affect cause marow depression?

Answer 39

Selective Depression of one cell line Unselective depression of all bone marrow elements (pancytopenia)

Question 40

Example of AM that suppresses marrow?

Answer 40

Linezolid (an anti-MRSA agent) can cause low platelet counts

Question 41

What haematological side effect can co-trimoxazole cause?

Answer 41

Inhibits folic acid synthesis -> a folate deiciency -> megaloblastic anaemia

Question 42

What antiviral blood levels must be monitored?

Answer 42

Zidovudine for HIV Ganciclovir for CMV