Chapter 8

Question 1

In which 5 groups do you have to check CK baseline before starting statins and why? What would be the threshold?

Answer 1

Personal or family history of muscular disorders/toxicity
High alcohol intake
Renal impairment
Hypothyroidism
Elderly

Increased risk of myopathy
Don’t start statins if >5x ULN CK
If CK raised but <5x ULN then prescribe a lower dose of statins

Question 2

What is the most important thing to check before starting someone on statins? Why?

Answer 2

ALT/AST
Statins are metabolised by the liver, so hepatic impairment will increase their levels and thus increase the risk of myopathy

Question 3

What is the threshold for ALT/AST before starting statins? When do you have to recheck?

Answer 3

> 3x ULN should not start statins/should discontinue

Repeat within 3 and 12 months of starting treatment

Question 4

What is the half life of phenytoin?

Answer 4

24 hours - so one measurement is ok - peak or trough, as long as it is within the threshold - there is unlikely to be diurnal variation

Question 5

When should routine serum lithium concentration be measured?

Answer 5

Weekly after initiation/dose change until stable
3 monthly thereafter
Additional measurements required if a patient develops disease or changes sodium or fluid intake

Question 6

What are patients advised to avoid if on lithium?

Answer 6

Low sodium diets - sodium depletion increases risk of toxicity

Question 7

Monitoring requirements: Statins

Answer 7

ALT/AST

CK if

• personal/family history of muscle disorders/toxicity
• elderly
• hypothyroidism
• renal impairment
• high alcohol intake

Question 8

Monitoring requirements: Lithium

Answer 8

Serum lithium concentration
U+Es
TFTs

Question 9

Monitoring requirements: Phenytoin

Answer 9

Plasma-phenytoin concentration

Question 10

Monitoring requirements: Methotrexate

Answer 10

FBC, renal and liver function tests

Question 11

Monitoring requirements: All antipsychotics

Answer 11

Prolactin
Physical health monitoring
ECG

Question 12

Monitoring requirements: Olanzapine

Answer 12

Fasting blood glucose
Blood lipids
Weight

Question 13

Monitoring requirements: Clozapine

Answer 13

FBC
Fasting blood glucose
Blood lipids
Weight

Question 14

How long do you have to measure FBC for in clozapine? What levels do you discontinue?

Answer 14

Weekly for 18 weeks
Fortnightly for a year
Then monthly thereafter

Leukocytes <3000
Neutrophils <1500
Discontinue and refer to haematologist

Question 15

Monitoring requirements: Amiodarone

Answer 15

TFTs
CXR
LFTs
serum K+

Question 16

Why do you need to get a baseline CXR before commencing amiodarone?

Answer 16

Risk of pulmonary fibrosis (ILD)

Question 17

Monitoring requirements: Digoxin

Answer 17

U+Es
Serum creatinine

due to digoxin being renally excreted and those with renal dysfunction are at increased risk of digoxin toxicity

Question 18

In whom do you need to measure plasma digoxin concentration?

Answer 18

Signs of toxicity
Non-compliance
Inadequate effect

Question 19

Monitoring requirements: Sodium valproate

Answer 19

LFTs - MOST IMPORTANT - due to hepatotoxicity

FBC