2. Oxalidinone

Question 1

Examples of oxalidinones

Answer 1

Linezolid

Question 2

Linezolid spectrum of activity

Answer 2

Narrow spectrum

Active against gram-positive organisms but has NO activity against gram-negative organisms

Question 3

Linezolid mechanism of action

Answer 3

Prevents protein synthesis so are bacteriostatic.
Linezolid is a reversible non-selective monoamine oxidase inhibitor (MOAI). It blocks the breakdown of monoamine such as dopamine, adrenaline and noradrenaline.

Question 4

Linezolid adverse reactions

Answer 4

Linezolid is associated with optic neuropathy, patients must report signs of blurred vision, changes to visual field and colour. Visual function must be monitored if treatment is over 28 days

Haemotopoietic disorders (such as thrombocytopenia, anaemia and leucopenia (low number of leukocytes)).

Question 5

Linezolid monitoring

Answer 5

Visual function must be monitored if treatment is over 28 days

Full blood counts are monitored weekly

Question 6

Linezolid interactions

Answer 6

As linezolid is a reversible non-selective monoamine oxidase inhibitor (MOAI). It blocks the breakdown of monoamine such as dopamine, adrenaline and noradrenaline thus raising blood pressure. This leads to hypertensive crisis

Tyramine is a monoamine. Patients must avoid consuming large amounts of tyramine rich foods (cheese, undistllled alcohol, fermented soya).

It should also not be given with another MOAI or within two weeks of stopping one. It should also be avoided with SSRI’s and 5HT1 agonists (triptans), pethidine, tricyclic antidepressants. Should not be given a beta agonist or a sympathomimetic.

Question 7

Linezolid indications

Answer 7

Complicated skin and soft tissue infections caused by MRSA and pneumonia.

Used as an alternative to vancomycin for treatment of MRSA