Infections

Question 1

TETRACYCLINE

Answer 1

• Hepatoxicity
• Lithium
• Isotretinoin= Benign intracranial hypertension
• Warfarin/ acecoumarol/ phenindione = increases anticoagulant effect

Dairy products decrease absorption of Demeclocycline, oxytetracycline, tetracycline

Antacids / Fe, Zn, Ca decrease absorption of tetracyclines- separate administration by 2-3 hours

Question 2

QUINOLONES

Answer 2

1. Quinolones + NSAIDS = Convulsions/ Seizures
2. Quinolones + Warfarin/Acecoumarol= Increased anticoagulant effect
3. Quinolones + Antacids = Decreased absorption of Quinolones. Take 2 hrs before or 4 hours after antacids
4. Levofloxacin + Fe/Zn = decrease exposure to oral levofloxacin
5. Ciprofloxacin + Calcium carbonate = decrease absorption of ciprofloxacin. Separate administration by 2 hours.

Question 3

PENICILLINS

Answer 3

1. Penicillins + MTX= MTX toxicity
2. Penicillins + Warfarin/ acecoumarol/ Phenindione= increased anticoagulant effect; increased bleeding risk
3. Ampicillin/amoxicillin + allopurinol= Skin rash
4. Flucloxacillin + hepatotoxic drugs= hepatotoxicity

Question 4

TRIMETHOPRIM

Answer 4

1. Trimethoprim + nephrotoxic drugs = nephrotoxicity
2. Trimethoprim + methotrexate = increased risk of adverse effects
3. Trimethoprim increases anticoagulant effects of acenocoumarol and warfarin
4. Trimethoprim increases risk of hyponatremia if taken with other drugs that cause hyponatraemia
5. Trimethoprim increases risk of hyperkalaemia if taken with other drugs that also cause hyperkalaemia

Question 5

MACROLIDES

Answer 5

Clarithromycin and erythromycin are Enzyme inhibitors
Clarithromycin and erythromycin cause QT prolongation
Clarithromycin + statins = risk of myopathy/rhabdomyolysis (stop statins whilst on clarithromycin)

Question 6

LINEZOLID

Answer 6

1.	Following drugs increases BP when given with linezolid
•	Adrenaline, Epinephrine, noradrenaline, norepinephrine , ephedrine
•	Buspirone 
•	Dobutamine 
•	Dopamine, levodopa 
•	B2 agonists
•	Methylphenidate 
•	Pseudoephedrine 

2. Serotonin syndrome
3. Risk of adverse effects = MAOIs ( avoid linezolid for 14 days after stopping MAOIs)

Question 7

CEPHALOSPORINS

Answer 7

Nephrotoxicity

Ceftriaxone increases risk of bleeding with acenocoumarol , warfarin and phenindione

Question 8

VANCOMYCIN

AMINOGLYCOSIDES

Answer 8

Interacts with other drugs that are:
• Nephrotoxic
• Ototoxicity