Pharmacology

Question 1

Liver enzyme inducers increase the metabolism of other drugs and thus decrease their effectivness.

Name some common liver enzyme inducers.

(PC BRAS)

Answer 1

P- Phenytoin

C - Carbamazepine

B - Barbiturates

R - Rifampicin

A - Alcohol

S - Sulphonylureas & St. John’s Wart

Question 2

What drugs are commonly affected by liver enzyme inducers?

Answer 2

1. Warfarin
2. Phenytoin
3. Oral Contraceptives.

Question 3

Liver enzyme inhibitors slow hepatic metabolism and thus increase the effectiveness of other drugs.

Name some of these drugs.

(AO DEVICES)

Answer 3

• A - Allopurinol & Amiodarone
• O - Omeprazole
• D - Disulfiram
• E - Erythromycin (And other macrolides)
• V - Valproate & Verapamil
• I - Isoniazid
• C - Cimetidine & Ciprofloxacin
• E - Ethanol
• S - Sulphonamides
• ALSO Grapefruit juice & Some Anti-retroviral drugs.

Question 4

Name the drugs most commonly affected by liver enzyme inhibitors.

Answer 4

1. Warfarin
2. Carbamazepine
3. Cyclosporin
4. Phenytoin
5. Theophylines

Question 5

Azathioprine’s effect is increased by what drug?

Answer 5

Allpurinol

Question 6

Ace inhibitors are decreased by what 2 common drugs?

Answer 6

NSAIDs and Oestrogens

Question 7

The effect of methotrexate can be increased by what common drugs?

Answer 7

• Aspirin
• NSAIDs
• And many antibiotics.

Question 8

The effect of zidovudine can be increased by what common drug?

Answer 8

Paracetamol (Increased marrow toxicity)

Question 9

The effect of valproate can be decreased by what common drugs?

Answer 9

• Carbamazepine
• Phenytoin
• Phenobarbitol

Question 10

The effect of oral contraceptives can be decreased by what common drugs?

Answer 10

• Antibiotics
• Rifampicin
• Carbamazepine
• Barbiturates