Therapeutic Drug Monitoring

Question 1

What are the signs of phenytoin toxicity?

Answer 1

Ataxia, nystagmus

Question 2

What are the signs of an insufficient dose of phenytoin?

Answer 2

Seizures

Question 3

What is the treatment for phenytoin toxicity?

Answer 3

Reduce dose

Question 4

What are the signs of digoxin toxicity?

Answer 4

Arrhythmias, heart block, confusion, xanthopsia (seeing yellow)

Question 5

What are the signs of an insufficient dose of digoxin?

Answer 5

Arrhythmias

Question 6

State two causes of digoxin toxicity

Answer 6

Hypokalaemia, renal impairment

Question 7

What is the treatment for digoxin toxicity?

Answer 7

Digibind

Question 8

What are the signs of lithium toxicity?

Answer 8

Tremor, lethargy, fits, arrhythmia, renal failure

Question 9

What is the sign of an insufficient dose of lithium?

Answer 9

Relapse of mania in bipolar disorder

Question 10

State three causes of lithium toxicity

Answer 10

Hyponatraemia, renal impairment, diuretics - all decrease excretion

Question 11

What is the treatment for lithium toxicity?

Answer 11

Reduce dose, may require haemodialysis

Question 12

What are the signs of gentamicin toxicity?

Answer 12

Tinnitus, deafness, nystagmus, renal failure

Question 13

How is gentamicin toxicity avoided?

Answer 13

Single daily dosing with monitoring of peak and trough level before next dose

Question 14

What are the signs of theophylline toxicity?

Answer 14

Arrhythmias, anxiety, tremor, convulsions

Question 15

What is the sign of an insufficient dose of theophylline?

Answer 15

No effect on bronchial smooth muscle

Question 16

Name three drugs which increase the serum level of theophylline

Answer 16

Erythromycin, cimetidine, phenytoin

Question 17

Name two conditions which increase the half-life of theophylline, and by how much

Answer 17

Smoking (4 to 8h), liver disease (4 to 30h)