Basic principles

Question 1

Commonest enzyme inducers? (PC BRAS)

Answer 1

Phenytoin
Carbamezapine
Barbiturates
Rifampicin
Alcohol (chronic excess)
Sulphonylureas

Question 2

Commonest enzyme inhibitors? (AODEVICES)

Answer 2

Allopurinol
Omeprazole
Disulfiram
Erythromycin
Valproate
Isoniazid
Ciprofloxacin
Ethanol (acute)
Sulphonamides

Question 3

Effect of:

a) enzyme inhibiting drugs
b) enzyme inducing drugs

Answer 3

a) increased levels of other drugs metabolized by CP450

b) decreased levels and hence effectiveness e.g. COCP

Question 4

Which classes of drug should be stopped before surgery? (ILACKOP)

Answer 4

Insulin
Lithium
Anticoagulants/antiplatelets
COCP/HRT
K-sparing diuretics
Oral hypoglycaemics
Perindopril (and other ACE inhibitors)

Question 5

What is the risk of metformin peri-operatively?

Answer 5

Patients are NBM; metformin risks lactic acidosis

Question 6

When should the COCP/HRT be stopped prior to surgery?

Answer 6

4 weeks

Question 7

When should K-sparing diuretics/ACE inhibitors be stopped prior to surgery?

Answer 7

Day of surgery

Question 8

What are examples of potassium sparing diuretics? (3)

Answer 8

Spironolactone
Eplerenone
Amiloride

Question 9

What are the basic principles for each drug prescription? (5)

Answer 9

Unambiguous
Prescribed generically
Written legibly in capitals with no abbreviation
Signed
Include the duration where treatment is not long-term

Question 10

For PRN prescriptions what information should be included in the prescription? (2)

Answer 10

The indication

The maximum frequency (e.g. “qds”) or maximum dose in 24h (e.g. 1g)