Quinolones

Question 1

What are generic and brand names of quinolones?

Answer 1

• Ciprofloxacin (Ciproxin)

* Levofloxacin (Evoxil)

Question 2

What is the method of action of quinolones?

Answer 2

• Inhibits DNA synthesis
• Aerobic gram -ve bacteria
• Newer quinolones can also work against gram +ve organisms

Question 3

What are the indications for quinolones?

Answer 3

• UTI
• Severe GI infection/travellers diarrhoea e.g. shigella, campylobacter
• LRTI
• Psudomonas aeruginosa – ciprofloxacin only

Question 4

What are the contraindications for quinolones?

Answer 4

• Risk of seizures – use with caution
• Growing e.g. children – risk of athropathy
• Risk factors for QT prolongation

Question 5

What are the side effects of quinolones?

Answer 5

• GI upset
• Immediate and delayed hypersensitivity
• Lowering of seizure threshold
• Hallucinations
• Inflammation and rupture of muscle tendons
• Prolong QT intervals → arrhythmias
• C.diff

Question 6

What drugs do quinolones interact with?

Answer 6

• Calcium – contains divalent cations which ↓ absorption and efficacy of quinolones
• Antacids – contains divalent cations which ↓ absorption and efficacy of quinolones
• Theophylline – ciprofloxacin inhibits some P450 enzymes, ↑ risk of toxicity
• NSAIDs - ↑ risk of seizures
• Prednisolone - ↑ risk of tendon rupture
• Antipsychotics – already prolongs QT interval
• Amiodarone – already prolongs QT interval
• Quinine – already prolongs QT interval
• SSRIs – already prolongs QT interval

Question 7

What organ eliminates quinolones?

Answer 7

Kidney