Macrolides

Question 1

How does macrolides work ?

Answer 1

• inhibits bacterial protein synthesis by binding to the 50s subunit of ribosome
• broad spectrum + bacteriostatic

Question 2

Name all macrolides available ?

Answer 2

Azithromycin
Clarithromycin
Erythromycin
Telithromycin
spiramycin

Question 3

How should you counsel patient to take azithromycin ?

Answer 3

1. azithromycin capsules, you should take them at least 1 hour before food or 2 hours after eating. If you have tablets or liquid, you can take them with or without food.
2. Do not take indigestion remedies 2 hours before or after you take this medicine

Question 4

What is the common side effects of azithromycin when used orally ?

Answer 4

arthralgia

Question 5

What are contraindications of azithromycin ?

Answer 5

With severe hepatic impairment.
Taking drugs that prolong the QT interval (for example amiodarone, sotalol, terfenadine, and amisulpride) — macrolides can also prolong the QT interval, which is a risk factor for Torsades de pointes.
With hypokalaemia, due to the risk of prolongation of the QT interval.
With a history of QT prolongation or ventricular cardiac arrhythmia, including Torsades de pointes.

Question 6

What are the cautions regarding macrolides ?

Answer 6

electrolyte disturbances (predisposition to QT interval prolongation); may aggravate myasthenia gravis; predisposition to QT interval prolongation

Question 7

Which macrolide has most gastro-intestinal s/e?

Answer 7

erythromycin, also leave two hour gap with indigestion remedies

Question 8

What is very common side effect of clarithromycin ?

Answer 8

taste disturbance

Question 9

For what type infections is telithromycin reserved ?

Answer 9

for B-lactam resistant infections

Question 10

What side effects can telithromycin cause ?

Answer 10

visual disturbances, hepatoxicicity and transient loss of consciousness- careful with driving : take first dose at bed

Question 11

For which infections is spiramycin used ?

Answer 11

toxoplasmosis

Question 12

How should you counsel people to take macrolides?

Answer 12

generally with food, but not azithromycin

Question 13

What are the side effects of macrolides ?

Answer 13

• GI effects: nausea, vomiting, abdominal discomfort, diarrhoea
• QT interval prolognation
• Hepatoxicity (cholestatic jaundice)
• ototoxicity at high doses

Question 14

What are the risk factors for QT prolongation ?

Answer 14

bradycardia, heart disease, hypoK, hypoMg, drugs that prolong QT interval

Question 15

Which two macrolides are potent enzyme inhibitors ?

Answer 15

Erythromycin and clarithromycin

Question 16

IF erythromycin or clarithormycin given with warfarin, what would happen ?

Answer 16

increases risk of bleeding

Question 17

If erythromycin or clarithromycin given with statins, what would happen ?

Answer 17

increased risk of myopathy