ophthalmic drugs: anti-infective drugs Flashcards Preview

Therapeutics > ophthalmic drugs: anti-infective drugs > Flashcards

Flashcards in ophthalmic drugs: anti-infective drugs Deck (118):
1

what are the 3 different therapeutic classes of anti-infective drugs

- Antibacterials
Topical
Oral
- Antivirals
- Anti-protozoals

2

what 2 forms is antibacterial drugs available in

- Topical
- Oral

3

even though anti infective drugs have a long shelf life, why do optometrists not stock them in practice

because they won't use them enough for us to have a stock of them and some of them need to be refrigerated so its a hassle

4

how much % do anti infective drugs count for as prescription ophthalmic drugs in the UK

17%

5

why is 17% an under estimation of anti infective drugs supplied in the UK

because that counts for prescription only, and many anti infective drugs are available OTC or pharmacists can supply chloramphenicol

6

when will a pharmacist decide to supply a px with chloramphenicol

only if the px is suspected of having acute bacterial conjunctivitis (and not for anything else)

7

what can an optometrist supply chloramphenicol to a px for that a pharmacist can't and how

as a POM drug which has a broader licence to treat post corneal abrasion
the optom will use a signed order where they write down the drug name and give it to the pharmacist

8

what do drugs exploit

the difference between human (eukaryotic) and bacterial (prokaryotic) cells

9

list 4 differences between bacterial cells and human cells

- Bacterial cells have a unique cell wall
- There are differences in their cell membrane
- Bacterial cells show differences in the mechanism of DNA and protein synthesis
- Bacterial cells have different biosynthetic pathways

10

what do the differences between human and bacterial cells form the basis for

the selective toxicity of anti-bacterial drugs

11

what are drugs that kill the cell called

bactericidal

12

what do bacteriostatic drugs do

inhibit growth of the bacteria

13

name 2 drugs which affect the cell wall synthesis

- Penicillins
- Cephalosporins

14

name 2 drugs affecting the bacterial cell membrane

- Polymyxin B
- Propamidine

15

name 4 drugs affecting bacterial protein synthesis

- Aminoglycosides
- Tetracyclines
- Chloramphenicol
- Fusidic acid

16

name a drug affecting bacterial DNA synthesis

Fluoroquinolones

17

name a drug affecting bacterial metabolism

Sulphonamides

18

what is the most common way that a anti bacterial drug works

affecting bacterial DNA synthesis

19

name 5 general considerations when selecting a antibiotic

- Spectrum of cover e.g.
Narrow vs broad
Single vs combination

- Penetration into appropriate tissue

- Mode of action

- Route of administration

- Side effects e.g.
Tolerability
Pregnancy / Lactation

20

what 2 variations come under spectrum of cover when choosing an antibiotic

Narrow vs broad
or
Single vs combination

21

what 2 examples of side effects need to be considered when choosing an antibiotic

- Tolerability
- Pregnancy / Lactation

22

what 2 examples of penetration into appropriate tissue needs to be considered when choosing an ophthalmic antibiotic

- topical
or
- injected into eye

23

give 4 examples of routes of administrations of anti bionics

- topical
- orally
- injection
- slow release implant

24

what is the name of the test to check the sensitivity of antibiotics

Kirby-Bauer Antibiotic Sensitivity test

25

when can the Kirby-Bauer Antibiotic Sensitivity test be carried out on a bacteria

once its isolated

26

list the steps of how the Kirby-Bauer Antibiotic Sensitivity test is carried out

- a colony of bacteria is picked off the agar plate
- emulsified in a small volume of saline and then spread on a sensitivity test agar plate
- a paper disc, which has been impregnated with various antibiotics, is placed on top of the culture
- which is then incubated at 37C for 18 hours
- zones of diameter are read around each antibiotic disc and compared with standard values to judge whether the zone size represents a sensitive, intermediate or resistant isolate

27

which condition is the Kirby-Bauer Antibiotic Sensitivity test the gold standard treatment for

bacterial keratitis
you take a biopsy of the ulcer to sample the bug that is growing

28

list the 3 antibiotics available to all registered optometrists

- Chloramphenicol
- Fusidic acid
- Propamidine (P medicine bought OTC)

29

what is the antibiotic Polymyxin B available to optometrists as

Additional supply (by those who took additional qualifications)

30

what type of antibiotics are available to independent prescribing optometrists

All anti-infectives available for the treatment of diseases of the eye and surrounding tissues
(only restriction is injections)

31

what type of antibiotics is chloramphenicol

- broad spectrum
- Bacteriostatic (may be bacteriocidal for some species at high concentration)
- resistance if fairly low

32

what is chloramphenicol not affective against

pseudomonas

33

what condition is linked with systemic use of chloramphenicol but very unlikely with topical chloramphenicol

aplastic anaemia and ‘Grey Baby Syndrome’

34

what is aplastic anaemia

a life threatening stem cell deficiency which will need a bone marrow transplant

35

what is grey baby syndrome

a condition which can occur if chloramphenicol is given intravenously to babies in high doses

36

what is the UKs first choice of drug for most ocular surface infections

topical chloramphenicol

37

what is chloramphenicol officially licensed for and give 3 examples

the treatment of superficial infections of the eye
e.g.
- bacterial conjunctivitis
- infective blepharitis
- prophylaxis following trauma

38

what is prophylaxis

a treatment of antibiotic given to px in order to avoid them getting a bacterial infection

39

what are the 2 different formulations and concentrations of POM chloramphenicol available in
what else are POM chloramphenicol available in addition to this

- Redidrops, 0.5% POM
- Chloromycetin Ophthalmic ointment, 1% POM
- unit dose (minims)

40

how often should POM chloramphenicol be used

1-2 drops every 3-6 hours for 1 week

41

what happened to chloramphenicol eyedrops in 2005

it was reclassified from POM to P for the treatment of acute bacterial conjunctivitis

42

when was chloramphenicol ointment reclassified from POM to P

2007

43

what is the mode of action of chloramphenicol

The binding of chloramphenicol to peptidyl transferase on the 50S ribosomal subunit prevents the incorporation of new amino acids to the growing peptide chain

it works by inhibiting bacterial synthesis, the ribosomes goes along the messenger RNA and you have a growing peptide chain thats standard in all cells. The ribosomes used in bacteria are different to ribosomes used in human cells, so chloramphenicol binds to bacterial ribosomes and inhibits the growth of that peptide chain

44

list the 5 isolates associated with bacterial conjunctivitis

- Stapha = Staph. aureus
- Staphe = Staph epidermis
- Haemop = Haemophilus species
- Pseudo = Pseudomonas
- Strep = Streptococcus species

45

what are the 2 bugs that are most common in bacterial conjunctivitis

- Stapha = Staph. aureus
- Staphe = Staph epidermis

46

which bug is rarely a cause of bacterial conjunctivitis

Pseudo = Pseudomonas

47

which bug is the next most common after staph to cause bacterial conjunctivitis

Strep = Streptococcus species

48

which bug is the most likely to cause bacterial conjunctivitis in children than in adults

Haemop = Haemophilus species

49

what did a randomised double blinded treatment of chloramphenicol in the treatment of bacterial conjunctivitis show

that people just get better without any treatment and shows no statistical difference between chloramphenicol and the placebo, so if you do nothing it is just as affective

50

what is the POM Fusidic acid effective against

a broad range of gram +ve organisms (particularly Staph. Aureus)

51

what type of antibiotic is fusidic acid

Bacteriostatic (may be bacteriocidal at high concentrations)

52

what is the antibiotic fusidic acid licensed for

for the treatment of bacterial conjunctivitis

53

why will fusidic acid be used instead of chloramphenicol

because you only need to put it in twice a day instead of 4x a day
is easy to use on children

54

give a reason where fusidic acid is not an appropriate agent for acute bacterial conjunctivitis in children

because it is ineffective against Gram-negative H influenzae, the most common causative pathogen in this population

55

name 2 off licence uses of fusidic acid

- prophylaxis following corneal abrasion
- blepharitis

56

what is the trade name of the only formulation of ophthalmic fusidic acid available

Fucithalmic, POM

57

what does it mean when a drug isn't licensed for that purpose but it still used

the drug company never ran clinical trials on these patients

58

how often should Fucithalmic, POM be applied

twice daily application

59

what form does fusidic acid come in and what advantage does this have

comes as a gel
so stays on the ocular surface much longer than eye drops

60

what makes fusidic acid a good ocular surface agent

it doesn't penetrate the ocular tissues and does not get as far as the aqueous

61

which bacterial bug does fusidic acid have good efficacy against

staphylococcus

62

what is the age group for chloramphenicol POM

> 1 month old

63

what is the age group for chloramphenicol P

> 2 years old

64

what is the instructed dose intake of chloramphenicol

- Put one drop into the affected eye(s) every 2 hours for 2 days, and then three times a day for 5 days.
- Ointment at bedtime

65

what is the age group of Fusidic acid 1% eye drops
Fucithalmic (POM)

> 1 month

66

what is the instructed dose intake of Fusidic acid 1% eye drops Fucithalmic (POM)

1 drop 2x per day for 7 days

67

why is the age group of the OTC/P chloramphenicol > 2 years old

because of the theoretical risk of grey baby syndrome

68

which drug was discontinued in October 2012 and what properties did it have

- POM Polymyxin B
- where chloramphenicol was not good against game -ve bugs, this drug was
- it attaches to and interferes with the functioning of the cell membrane of aerobic Gram-negative bacteria, and bacitracin inhibits the synthesis of the cell wall of Gram-positive bacteria.

69

which bacterial bug was the POM Polymyxin B active against

P aeruginosa

70

which drug is active against gram +ve bacteria but less active against gram -ve bacteria, and also has anti fungal and anti amoebic properties
what treatment is it used for

OTC Propamidine
used topically for the treatment of minor eye infections such as conjunctivitis and blepharitis
it is an Aromatic diamidine disinfectant

71

OTC Propamidine is not an antibiotic, but is an

Aromatic diamidine disinfectant

72

how does OTC Propamidine work

by acting on the bacterial cell membrane, it increases it's cell permeability and is bacteriostatic

73

what is OTC Propamidine used by ophthalmologists for

patients who come into A&E with acanthamoeba keratitis

74

what are the 2 different formulations of (P) propamidine available

- Brolene
- Golden eye ointment

75

what is (P) propamidine licensed for

treatment of superficial infections of the eye
e.g. bacterial conjunctivitis and infective blepharitis

76

what is the instructed dose intake of (P) propamidine

1-2 drops up to 4x daily

77

what did pharmacists used prior to chloramphenicol as an anti-infective agent

(P) propamidine

78

list 4 other anti-bacterials that are used in ophthalmology

- Quinolones
- Aminoglycosides
- Tetracylines
- Azithromycin

79

how does the ophthalmological anti bacterial Quinolones work

Inhibit DNA gyrate

they're broad spectrum drugs

80

list 4 examples of Quinolones

- Ofloxacin
- Ciprofloxacin
- Levofloxacin
- Moxifloxacin

81

name the 2 newer generation Quinolones anti bacterials and why are there newer generation ones out

- Levofloxacin
and
- Moxifloxacin

newer ones are added all the time because the old ones become useless as so many bacteria become resistant to them, therefore companies have to develop new ones to stay one step ahead of the bacteria

82

how does the ophthalmological anti bacterial Aminoglycosides work

Inhibits protein synthesis
is bactericidal

they're broad spectrum drugs

83

what is a disadvantage of the ophthalmological anti bacterial Aminoglycosides

they are toxic to the ocular surface especially thick corneas

84

name 2 examples of the ophthalmological anti bacterial Aminoglycosides

- Gentamicin
- Tobramycin

85

how does the ophthalmological anti bacterial drug Tetracylines work

Inhibit bacteria protein synthesis by blocking the attachment of the transfer RNA-amino acid to the ribosome

they're broad spectrum drugs

86

what is the ophthalmological anti bacterial drug Tetracylines used to treat

lid margin disease

87

name 2 examples of the ophthalmological anti bacterial drug Tetracylines

- Doxycycline
- Minocycline

88

how is the ophthalmological anti bacterial drug Tetracylines administered

orally
instead of topically

89

what 2 things is the ophthalmological anti bacterial drug Azithromycin licensed for

- trachomatous conjunctivitis caused by Chlamydia trachoma's
- acute bacterial conjunctivitis

90

what is the off license use for the ophthalmological anti bacterial drug Azithromycin

to treat blepharitis

91

what are viruses and how do they work

- intracellular parasites
- they need to take over cells in order to divert that cells machinery for producing proteins and DNA into synthesising and assembling new viruses
- so an single virus infects and then sheds multiple viruses which go on to infect other cells = how the virus propagates

92

what is the most common virus of the eye and what does it cause

- herpes simplex HSV
- same virus that causes the chickenpox can be reactivated and cause cold sores and herpes simplex keratitis

93

why is the herpes simplex HSV a problem

because following primary infection e.g. chicken pox, you don't completely eradicate the virus and it tends to become latent where it travels down the sensory nerves and sits within the trigeminal ganglion, to be subsequently reactivated

94

which type of patients are most likely to re-contract the herpes simplex virus HSV

the immunocompromised e.g HIV +ve or on steroids

95

what type of virus are herpes virus

DNA viruses

96

name 3 examples of the herpes virus

- Herpes Simplex
- Varicella zoster
- Cytomegalovirus

97

name 3 properties of HSV

- Primary
- Recurrent
- Congenital

98

which type of HSV is most common

HSV-1

99

what do 60% of children have and by when

HSV by 5 years

100

which type of HSV is most congenital

HSV-1
80%

101

what ocular signs are recurrent in HSV

- Thin dendritic ulcers
- Contain live virus

102

what ocular signs is found with Varicella zoster VSV

Ophthalmic shingles

103

how many Varicella zoster VSV patients with periocular shingles have eye involvement

50-72%

104

which type of patients can the Cytomegalovirus CMV infections occur in

immunocompromised individuals e.g. AIDS, post-transplant

105

what does the Cytomegalovirus CMV present as in the eye

a viral necrotizing retinitis
which is sight threatening

106

which herpes virus infects the back of the eye rather than the front

Cytomegalovirus CMV

107

which antiviral drug treats herpes simplex keratitis

aciclovir

108

how does the drug acyclovir which treats herpes simplex keratitis work and what is the mechanism for this

by inhibiting viral DNA synthesis

-Aciclovir enters the cell and is
converted to aciclovir monophosphate by the herpes simplex virus enzyme thymidine kinase (TK).
- Enzymes add two more phosphates to form the active drug aciclovir triphosphate.
- The aciclovir triphosphate competes with 2- deoxyguanosine triphosphate (dGTP) as a substrate for viral DNA polymerase.

in other words:
- the process assembles nucleotides to produce DNA
- but when the aciclovir gets inside the cell its phosphorylated and so binds to one of the virus's enzymes. - the phosphate is added and turns into aciclovir triphosphate and then the cell thinks that the aciclovir triphosphate is one of the DNA precursors, so it tries to incorporate it into the DNA synthesis and therefore it inhibits the process of synthesis

109

what drug is used to treat the sight threatening viral necrotising retinitis caused by the Cytomegalovirus CMV

ganciclovir

110

what is ganciclovir and how is it administered

- Slow-release ocular implant
- inserted into the eye surgically

111

what is the epidemiology of acanthamoeba

a free living amoeba found in water / Soil

112

what are the 2 life cycles of acanthamoeba

- Mobile trophozoites
and
- Dormant cysts

113

what 3 things is acanthamoeba resistant to

- freezing
- drying
- chlorine

114

what is acanthamoeba cultured as

Specialised, Non-nutrient agar / E. coli

115

what are the choices of drug and concentration for treating acanthamoeba

- Propamidine 0.1% and Polyhexamethylene biguanide (PHMB) 0.02%
- Chlorhexidine 0.02%

116

how often should the drugs to treat acanthamoeba be administered

hourly day and night for 2 days then reduce as condition improves

117

which drugs to treat acanthamoeba have activity against the cyst form

- Polyhexamethylene biguanide (PHMB)
and
- Chlorhexidine

118

what stage of acanthamoeba keratitis will no drug be effective and what will be the only thing to treat it

- ring infiltrate
- will need corneal transplant