CLASSES OF ABX: QUINOLONES

Question 1

Examples

Answer 1

Ciprofloxacin
Levofloxacin
Moxifloxacin
Norfloxacin
Ofloxacin

Question 2

MOA

Answer 2

Inhibit topoisomerases, enzymes necessary for bacterial DNA replication.

Question 3

Side effects

Answer 3

• Suicidal thoughts and behaviour (psychiatric reactions)
• May induce convulsions
• Tendonitis
• GI side-effects
• QT interval prolongation
• Hypersensitivity/severe rash

Question 4

Contraindications and cautions

Answer 4

1. QT
2. Children or adolescents - aropathy
3. Diabetes
4. Epilepsy
5. Exposure to excessive sunlight
6. Psychiatric disorders
7. Pregnancy

Question 5

Ciprofloxacin - indications

Answer 5

RTIs (not pneumococcal pneumonia)
Infections of GI systems (including typhoid)
Bone + joint infections
Gonorrhoea
Septicaemia

Question 6

MHRA Drug Safety Update Jan 2024:

Answer 6

Systemic fluoroquinolones must only be prescribed when other commonly recommended antibiotics are inappropriate.

Question 7

Why must quinolones only be prescribed when other commonly recommended antibiotics are inappropriate?

Answer 7

This is to reduce the identified risk of disabling and potentially long-lasting or irreversible side effects.

Question 8

Quinolones + convulsions

Answer 8

Quinolones may induce convulsions in patients with or without a history of convulsions.
Increased risk with NSAIDs

Question 9

Increased risk of seizures

Answer 9

Ciprofloxacin + theophylline
Pk and Pd interaction
Ciprofloxacin is an enzyme inhibitor - causes theophylline toxicity
Theophilline SE = convulsions

Question 10

Quinolones + tendonitis

Answer 10

Tendon damage (including rupture) has been reported rarely within 48hrs.
o More common in patients over 60
o If suspected. STOP and seek medical attention

Question 11

Quinolones + small risk of aortic aneurysm and dissection

Answer 11

o Seek medical attention
 Sudden onset severe abdominal, chest or back pain

Question 12

Quinolones + small risk of heart valve regurgitation

Answer 12

Consider other therapeutic options first in those with:
- Congenital or pre-existing heart valve disease
- Connective tissue disorders

o Seek medical attention
 Shortness of breath, peripheral oedema, new heart palpitations

Question 13

Other risk factors predisposing to heart valve regurgitations

Answer 13

hypertension, RA, infective endocarditis

Question 14

Quinolones + QT prolongation

Answer 14

Ventricular arrhythmias
ESPECIALLY moxifloxacin (C/I in risk factors for QT prolongation)

Question 15

Risk factors for QT prolongation

Answer 15

Electrolyte disturbances
Acute MI
HF with reduced LVEF
Bradycardia
Congenital long QT syndrome
Concomitant QT prolongation drugs
Symptomatic arrhythmias

Question 16

Quinolones + aneurysm

Answer 16

Factors that increase risk:
- FH of aneurysm disease
- Pre existing aortic aneurysm/aortic dissection
- Other risk factors predisposing to aortic aneurysm (e.g. hypertension + atherosclerosis)

Question 17

Interactions

Answer 17

• QT
• NSAIDs
• Alcohol

Question 18

What food and drink to avoid

Answer 18

o Avoid dairy and mineral-fortified drinks – reduces absorption

Question 19

Counselling points

Answer 19

Driving - can impair performance of skilled tasks; increased effect when taken with alcohol
Antacid and zinc/iron - 2 hours before or after taking
Milk - avoid milk with ciprofloxacin and norfloxacin
Protect skin from sunlight + avoid sunbeds
Avoid NSAIDs

Question 20

Which should not be taken with milk?

Answer 20

NOrfloxacin
CIProfloxacin

Question 21

not to be taken with indigestion remedies…

Answer 21

levo
moxi
oflox

can be taken with milk

Question 22

Which must be taken on an empty stomach

Answer 22

Norfloxacin