49. Macrolides

Question 1

What are macrolides?

Answer 1

are a group (class) of antibiotics that treat bacterial infections. Macrolides work by preventing bacteria from growing

Question 2

Active substances of macrolides

Answer 2

• erythromycin
• azithromycin
• clarithromycin
• spiramycin
• tylosin
• tylvalosin
• tilmicosin
• tulathromycin
• gamithromycin
• tildipirosin

Question 3

Mechanism of action of macrolides

Answer 3

Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. The bacterial ribosomes are essential for protein synthesis, and the proteins are vital for bacterial growth.
The inhibition of these ribosomes will effectively halt bacterial replication

Question 4

AB spectrum of macrolides

Answer 4

Question 5

Pharmacokinetics of macrolides

Answer 5

1. Absorption
Oral: variable
IM, SC: good, but can cause irritation

2. Distribution
Good, but do not cross BBB

3. Metabolism
Liver

4. Excretion
90% in bile

Question 6

Side effects of macrolides

Answer 6

• GI-irritation: Vomiting, diarrhoea
• Dysbacteriosis in horses and herbivores
• Fatal enterocolitis, especially in foals. Adult horses are more resistant
• Tissue irritation
• Cardiotoxicity: especially by tilmicosin!

Question 7

Azithromycin

Answer 7

Oral application, excellent absorption and distribution.
Very good against gram+

Question 8

Clarithromycin

Answer 8

Oral application, excellent absorption and distribution.
Very good against gram+

Question 9

Tylvalosin

Answer 9

Oral administration, a relative new drug
Very good against fastidious organism and mycoplasma

Question 10

Tylosin

Answer 10

Frequent resistance !
Oral administration

Question 11

Tilmicosin

Answer 11

!! FORBIDDEN IN GOATS !!
This is the most toxic macrolide in horses, goats and humans.
Given to pigs orally.
Good against fastidious gram- and mycoplasma

Question 11

Tulathromycin

Answer 11

Injection drug in ruminants and pigs
Very good against fastidious organism and mycoplasma