Macrolides

Question 1

Can macrolides be used in patients with a penicillin allergy?

Answer 1

Yes

The macrolides have an antibacterial spectrum that is similar but not identical to that of penicillin; they are thus an alternative in penicillin-allergic patients

Question 2

Name 4 macrolides?

Answer 2

Azithromycin
Clarithromycin
Erythromycin
Spiramycin

Question 3

Which sexually transmitted infections can erythromycin be used to treat?

Answer 3

1. Early syphilis
   - 500 mg 4 times a day for 14 days (oral)
2. Uncomplicated genital chlamydial infection
   - 500 mg twice daily for 14 days (oral)
3. Non-gonococcal urethritis
   - 500 mg twice daily for 14 days (oral)

Question 4

Erythromycin has (?) activity against Haemophilus influenzae

Answer 4

poor

Question 5

Is erythromycin active against Legionella?

Answer 5

Yes

Question 6

Can erythromycin be used in the treatment of pertussis in a child?

Answer 6

Yes
- dose depends on age of child

Also used in prevention of pertussis

Question 7

How do you avoid the side effects such as nausea, vomiting and diarrhoea in patients taking erythromycin for a mild-to-moderate infection?

Answer 7

Give a lower dose

Erythromycin causes nausea, vomiting, and diarrhoea in some patients; in mild to moderate infections this can be avoided by giving a lower dose, but if a more serious infection, such as Legionella pneumonia, is suspected higher doses are needed.

Question 8

Which macrolide is used in the treatment of rosacea?

Answer 8

Erythromycin (oral)

- 500 mg twice daily courses usually last 6-12 weeks and are repeated intermittently

Question 9

(Azithromycin/Erythromycin) is a macrolide with slightly less activity than (azithromycin/erythromycin) against Gram-positive bacteria.

Answer 9

Azithromycin is a macrolide with slightly less activity than erythromycin against Gram-positive bacteria.

But enhanced activity against some Gram-negative organisms including H. influenzae.

Question 10

Azithromycin is a macrolide with slightly less activity than erythromycin against Gram-(?) bacteria.

Answer 10

positive

But enhanced activity against some Gram-negative organisms including H. influenzae.

Question 11

Systemic use of erythromycin should be avoided in patients with acute …

Answer 11

porphyrias

Question 12

Why is systemic erythromycin avoided in neonates under 2 weeks old?

Answer 12

Risk of hypertrophic pyloric stenosis

Question 13

Side effects are most common and severe with which macrolide?

Answer 13

Erythromycin

Question 14

Because macrolides are an irritant, what are the most common side effects?

Answer 14

Nausea
Vomiting
Abdominal pain
Diarrhoea

Question 15

At high doses, macrolides may cause (???) predisposing patients to arrhythmias

Answer 15

QT interval prolongation

Question 16

Which macrolide can cause hearing loss after large doses?

Answer 16

Erythromycin

A side effect of all macrolides in hearing impairment.

Question 17

Which two macrolides inhibit cytochrome P450 (CYP) enzymes?

Answer 17

Erythromycin
Clarithromycin

Increases plasma concentrations and the risk of adverse effects with drugs metabolised by CYP enzymes

Question 18

If a patient is taking both erythromycin (or clarithromycin) and warfarin, what does the interaction cause?

Answer 18

Increased risk of bleeding

Question 19

In a patient with severe renal impairment, why is the max dose of erythromycin 1.5g daily?

Answer 19

Increased risk of ototoxicity

Question 20

Which macrolide is indicated for use in gastro-intestinal stasis?

Answer 20

Erythromycin

Question 21

Is clarithromycin indicated for use in the treatment of pertussis?

Answer 21

No

But indicated for prevention of pertussis

Question 22

Which macrolide has greater activity against Haemophilus influenzae - erythromycin or azithromycin?

Answer 22

Azithromycin

Question 23

Which macrolide antibiotic is used in regimens for Helicobacter pylori eradication?

Answer 23

Clarithromycin

Question 24

Spiramycin is used for treatment of which infection?

Answer 24

Toxoplasmosis

Question 25

Which macrolide is used for the treatment of toxoplasmosis?

Answer 25

Spiramycin