Macrolides

Question 1

Which of the following macrolides is administered once daily?
A. Erythromycin
B. Clarithromycin
C. Azithromycin
D. Roxithromycin

Answer 1

Correct answer: C. Azithromycin.
Explanation: Azithromycin has a long half-life, allowing once-daily dosing, unlike erythromycin and clarithromycin which are usually given multiple times daily.

Question 2

Which macrolide is preferred during pregnancy?
A. Azithromycin
B. Clarithromycin
C. Erythromycin
D. Telithromycin

Answer 2

Correct answer: C. Erythromycin.
Explanation: Erythromycin is the preferred macrolide in pregnancy due to the longest safety record. Clarithromycin should be avoided unless benefit outweighs risk.

Question 3

Macrolides should be used with caution in patients with which neuromuscular condition?
A. Multiple sclerosis
B. Myasthenia gravis
C. Parkinson’s disease
D. Epilepsy

Answer 3

Correct answer: B. Myasthenia gravis.
Explanation: Macrolides can worsen neuromuscular transmission and exacerbate myasthenia gravis.

Question 4

Macrolides should be avoided in patients with a predisposition to which cardiac abnormality?
A. Bradycardia
B. Heart block
C. QT prolongation
D. Atrial fibrillation

Answer 4

Correct answer: C. QT prolongation.
Explanation: Macrolides prolong the QT interval and increase the risk of torsades de pointes.

Question 5

Which electrolyte abnormality increases the risk of macrolide-induced QT prolongation?
A. Hypernatraemia
B. Hyperkalaemia
C. Hypokalaemia
D. Hypercalcaemia

Answer 5

Correct answer: C. Hypokalaemia.
Explanation: Low potassium levels increase the risk of QT prolongation and arrhythmias with macrolides.

Question 6

Macrolides should be used cautiously in patients with which organ impairment?
A. Mild renal impairment only
B. Severe hepatic or renal impairment
C. Mild hepatic impairment only
D. Respiratory impairment

Answer 6

Correct answer: B. Severe hepatic or renal impairment.
Explanation: Macrolides are metabolised hepatically and partially renally, increasing toxicity risk in severe impairment.

Question 7

What is the most common side effect associated with macrolides?
A. Bone marrow suppression
B. GI disturbances
C. Renal failure
D. Photosensitivity

Answer 7

Correct answer: B. GI disturbances.
Explanation: Diarrhoea, nausea, vomiting, and taste perversion are the most common macrolide adverse effects.

Question 8

Which sensory adverse effect may occur with macrolides, especially at high doses?
A. Visual loss
B. Tinnitus and hearing loss
C. Peripheral neuropathy
D. Taste loss only

Answer 8

Correct answer: B. Tinnitus and hearing loss.
Explanation: Macrolides can cause ototoxicity and reversible hearing loss, particularly at high doses.

Question 9

Macrolides are associated with which cardiac adverse effect?
A. Bradycardia
B. Heart failure
C. QT prolongation
D. Hypertension

Answer 9

Correct answer: C. QT prolongation.
Explanation: QT prolongation is a known class effect and a major safety concern.

Question 10

Which hepatic adverse effect can occur with macrolide therapy?
A. Fatty liver disease
B. Hepatotoxicity
C. Cirrhosis
D. Portal hypertension

Answer 10

Correct answer: B. Hepatotoxicity.
Explanation: Macrolides can cause liver enzyme elevation and hepatotoxicity.

Question 11

Which macrolides are CYP enzyme inhibitors?
A. Azithromycin only
B. Clarithromycin and erythromycin
C. All macrolides
D. Erythromycin only

Answer 11

Correct answer: B. Clarithromycin and erythromycin.
Explanation: These two inhibit CYP3A4, increasing concentrations of many interacting drugs. Azithromycin has minimal CYP inhibition.

Question 12

Which medication may have increased levels when given with clarithromycin or erythromycin?
A. Paracetamol
B. Rivaroxaban
C. Metformin
D. Amoxicillin

Answer 12

Correct answer: B. Rivaroxaban.
Explanation: CYP inhibition increases rivaroxaban levels, raising bleeding risk.

Question 13

What is the correct action when prescribing a macrolide with a statin?
A. Increase statin dose
B. Continue statin as normal
C. Stop statin temporarily
D. Switch macrolide to azithromycin only

Answer 13

Correct answer: C. Stop statin temporarily.
Explanation: Macrolides increase statin levels, increasing the risk of myopathy and rhabdomyolysis.

Question 14

Which drug class increases the risk of hypokalaemia when used with macrolides?
A. ACE inhibitors
B. Loop diuretics
C. Potassium supplements
D. ARBs

Answer 14

Correct answer: B. Loop diuretics.
Explanation: Loop diuretics cause potassium loss, increasing QT prolongation risk.

Question 15

Which of the following drugs increases QT prolongation risk when combined with macrolides?
A. Metformin
B. Domperidone
C. Amoxicillin
D. Calcium carbonate

Answer 15

Correct answer: B. Domperidone.
Explanation: Domperidone prolongs the QT interval, significantly increasing arrhythmia risk when combined with macrolides.

Question 16

Which SSRI-related concern applies when prescribing macrolides?
A. Reduced antidepressant effect
B. Increased sedation
C. QT prolongation
D. Hyponatraemia

Answer 16

Correct answer: C. QT prolongation.
Explanation: SSRIs can prolong QT interval, and combined use with macrolides increases arrhythmia risk.