Antimicrobial prescribing

Question 1

What is the typical amoxicillin prescription?

Answer 1

Amoxicillin capsules 500mg
- 500mg 3x daily for 5 days

Amoxicillin oral suspension 250mg/5ml

• 6-12yrs 2x5ml spoonfuls 3x daily for 5 days
• 1-5yrs 1x5ml spoonful 3x daily for 5 days
• <12mnths 1/2 5ml spoonful 3x daily for 5 days

Question 2

Why would you prescribe amoxicillin?

Answer 2

1st line for bacterial infections such as dental abscesses.

Used for patients that cannot take metronidazole.

Question 3

What is the action of amoxicillin?

Answer 3

It is a beta-lactam which inhibits cell wall synthesis leading to bacterial lysis.
It is bactericidal.

Question 4

Why would you prescribe metronidazole?

Answer 4

Used for anaerobic bacterial infections, 2nd line for dental abscesses and patients who cannot take amoxicillin.
Can be used as an adjunct to amoxicillin in patients with spreading infection or pyrexia.
Used for ANUG and pericoronitis.

Question 5

What is the action of metronidazole?

Answer 5

It inhibits nucleic acid synthesis which disrupts DNA microbial cells.

Question 6

What is the standard metronidazole prescription for dental abscesses or for adjunctive treatment?

Answer 6

Metronidazole tablets 400mg:
- 400mg 3x daily for 5 days

Metronidazole 200mg/5ml oral suspension:
7-10yrs: 1x5ml 3x daily for 5days
3-7yrs: 1x5ml 2x daily for 5days
1-3yrs: 1/2x5ml 3x daily for 5days

Question 7

What is the standard metronidazole prescription for pericoronitis and NUG?

Answer 7

Metronidazole tablets 400mg

- 400mg 3x daily for 3 days

Question 8

What is the standard clarithromycin prescription?

Answer 8

Clarithromycin tablets 250mg

- 250mg 2x daily for 5days

Question 9

What is the action of macrolides?

Answer 9

Inhibit bacterial protein biosynthesis

E.g. clarithromycin, clindamycin used for Protozoa infections

Question 10

What medication is used for PHG in immunocompromised patient?

Answer 10

Aciclovir:
>3yrs: 200mg 5x daily for 5 days
<3yrs: 100mg 5x daily for 5days or oral suspension 200mg/5ml

Question 11

What is the standard management of PHG?

Answer 11

Plenty bed rest
Increased fluid intake 
Soft diet
Antipyretics
Antimicrobial MW such as CHX or benzydamine for pain relief and oral cleanliness

Question 12

What causes PHG?

Answer 12

Caused by herpes simplex virus common in young children/adults with incubation period of 5 days.

Question 13

What causes herpes labialise?

Answer 13

More commonly known as cold sores it is when herpes simplex virus remains latent in trigeminal ganglion and is reactivated due to a stimulus.

Question 14

What is the management of herpes labialis?

Answer 14

Aciclovir cream:

- 5% cream to lesions every 4hrs (5x daily) for 5-10 days starting at first sign of infection

Question 15

What medication is used in herpes zoster varicella shingles?

Answer 15

Aciclovir:
- 800mg 5x daily for 7 days
Urgent referral for children and to ophthalmology when eyes are involved.
Should be started 72hrs on set of rash

Question 16

What are the 3 classes of antifungal agents?

Answer 16

Polyene topical:
- nystatin suspension
Imidazole topical:
- miconazole oromucosal gel, cream or combined prep
Triazole:
- fluconazole oral suspension of capsules

Question 17

What are the standard prescriptions for antifungals?

Answer 17

Nystatin 100,000 units
- 4x daily after food for 7days continued 2 days after lesions have healed - hold against lesion for 5mins before swallowing.

Miconazole 2.5ml:
- 4x daily after meals retained near lesion before swallowing and continue for 7 days after lesions have healed

Miconazole gel
- 5-10ml to affected area 4x daily until 48hrs after lesions resolve - dentures inserted to keep gel in place

Fluconazole 50mg
- 50mg 1x daily for 7-14 days

Question 18

What type of Candida infection is considered pre malignant?

Answer 18

Chronic hyperplastic candidosis

- should be biopsied and referral to specialist

Question 19

A pt attends with an acute dental abscess. There is facial swelling evident, patient feels slightly feverish and there is tenderness of submandibular nodes. The patient has allergy to penicillin and is taking statins. What antimicrobial regimen should they have?

Answer 19

Metronidazole 400mg 3x daily for 5 days