Antibiotics (antibacterials)

Question 1

Contraindications

Answer 1

• allergic reactions
• toxicity
• development of resistant strains

Question 2

Caution of use

Answer 2

Use in pregnancy
Lactating mothers
Children under 1 yr

Question 3

Dosage

Answer 3

As per manufacturer - general:

• post Sx = qid for 1 wk
• bact conj = qid for 1 wk
• severe bact conj = q2-4h 2d, if improv qid for 5d
• bact keratitis = q1h die & nocte 48 hrs, decrease with clinical response, q2h d, q4h n for 2d then qid for 2 wks

Question 4

Quinolones - uses

Answer 4

Bacterial keratitis
Severe bact conj

NB- ciprofloxacin may precip temp white precips. Ofloxacin is more soluble in cornea

Question 5

Quinolones Paediatric use

Answer 5

Approved down to 1 yr

Except Iquix - 6 yrs and older

Question 6

Quinolones - sensitivity

Answer 6

Broad spectrum, some resistant Gram+ cocci
Fluoroquinolones may be ineffective against MRSA due to systemic use
Besifloxacin - ophthalmic only

Question 7

Quinolones - preparations

Bactericidal

Answer 7

Ciloxan - 0.3% ciprofloxacin - Alcon + generic
Ocuflox - 0.3% ofloxacin - Allergan + generic
Zymar - 0.3% gatifloxacin - Allergan
Zymaxid - 0.5% gatifloxacin - Allergan
Quixin - 0.5% levofloxacin - Vistakon
Iquix - 1.5% levofloxacin - Vistakon . Unpreserved
Vigamox - 0.5% moxifloxacin - Alcon. Unpreserved
Besivance - 0.6% besifloxacin susp - B&L # Invert & shake #

Question 8

Bactericidal amino glycosides - uses

Answer 8

Bact conj
Prophylaxis follow Sx or Occ surface trauma - abrasions
Fortified preps used in dual Tx with cephalosporin for bact keratitis

Question 9

Bactericidal amino glycosides - sensitivity

Answer 9

Broad spectrum antibiotic with some gram+ resistance

Seldom used systemically thus might be effective against MRSA

Question 10

Bactericidal amino glycosides - preps

Answer 10

Genoptic - 0.3% gentamicin drops - Allergan & generic
Fort gentamicin 1.3% - non-commercial
Tobrex - 0.3% tobramycin drops & ointment - Alcon & generics
Fort tobramycin 1.3% - non-commercial

Question 11

Vancomycin

Bactericidal

Answer 11

Ophth use reserved for serious infection:
Infect cryst keratopathy, endophthalmitis, MK
IV
Tricyclic glycopeptide
Inactive against gram- bacilli

Question 12

Cephazoline

Bactericidal

Answer 12

Fort prep used in dual Tx with amino glycoside for

Bact keratitis & endophthalmitis

Question 13

Chloramphenicol - uses

Answer 13

Bact conj
Prophylaxis follow Sx and Occ surface trauma

Broad sensitivity in gram- & gram+ , resistance common

Question 14

Chloramphenicol - caution

Answer 14

FH of blood disorders
Bone marrow suppressive agents
Needing prolonged Tx - pos aplastic anaemia
Non-prescription in Aus - pharmacy only

Question 15

Chloramphenicol - preps

Answer 15

Minims chloramphenicol sol 0.5% - B&L
Chlorsig 0.5% drops and 1.0% ointment - Sigma
Chloromycetin 0.5% drops & 1.0 % ointment - Phizer & generic

General dosage