Drugs & Monitoring

Question 1

What is phenytoin given for?

Answer 1

Seizures:

a voltage-gated, sodium channel blocker

Question 2

What are the signs of toxicity for Phenytoin?

Answer 2

Ataxia

Nystagmus

Question 3

What cautious are suggested when prescribing phenytoin?

Answer 3

At high levels the liver becomes saturated = surge in blood levels

Question 4

What is digoxin prescribed for?

Answer 4

Arrythmias

Question 5

What are the signs for digoxin toxicity

Answer 5

Arrythmias (ironically)
heart block
confusion

Xanthopsia = seeing yellow - green

Question 6

What cautious are suggested when prescribing digoxin?

Answer 6

Reduce dose in renal failure and in elderly

hypokalaemia can worsen digoxin toxicity

Question 7

What can worsen digoxin toxicity?

Answer 7

Hypokalaemia

Question 8

How to treat digoxin toxicity?

Answer 8

Digibind

(digoxin immune fab)

Question 9

What is lithium prescribed for?

Answer 9

Relapses of mania in bipolar disorder

Question 10

Signs of lithium toxicity?

Answer 10

Tremor
Lethargy
Fits
Arrhythmia
Renal failure

Question 11

What cautions are recommended when prescribing lithium?

Answer 11

be cautious if low renal function and use of diuretics (increase lithium in blood)

Excretion also impaired by hyponatraemia

Question 12

What can impair excretion of lithium?

Answer 12

Hyponatraemia

Question 13

How to manage lithium toxicity?

Answer 13

Alkaline diuresis

if 3+ = haemodialysis

Question 14

Give examples of aminoglycosides?

Answer 14

Gentamicin

Vancomycin

Question 15

What are amniglycosides used for?

Answer 15

Uncontrolled infection

Question 16

Amniglycoside toxicity symptoms?

Answer 16

(ototoxicity)

Tinnitus
Deafness
Nystagmus
Renal failure

Question 17

How to manage prescribing aminoglycosides?

Answer 17

Use single daily dosing

Monitor peak and trough levels before next dose

Question 18

What is theophylline / aminophylline prescribed for?

Answer 18

Bronchial smooth muscle which doesnt relax e.g.

COPD
Asthma

Question 19

Signs of theophylline toxicity?

Answer 19

Arrythmias
Convulsions
Anxiety
tremor

Question 20

What variations in half life need to be considered when prescribing theophylline?

Answer 20

4 hours in smokers
8 hours in non smokers
30 hours in liver disease

Question 21

Which drug interactions increase blood levels of theophylline?

Answer 21

Erythromycin
Cimetidine
Phenytoin

Question 22

What does it mean if a drug is a CYP450 substrate?

Answer 22

drugs (or substances) that are metabolised by the cytochrome P450 (CYP450) enzymes in the liver

Anything that inhibits or induces these enzymes can affect drug levels in the body.

Question 23

If a CYP450 inhibitor is taken with a CYP450 substrate ?

Answer 23

drug stays in the body longer → risk of toxicity.

Question 24

If a CYP450 inducer is taken with a CYP450 substrate

Answer 24

the substrate drug is broken down faster → reduced effectiveness.

Question 25

Give me examples of CYP450 substrates?

Answer 25

Warfarin Antiepileptic drugs OCP Prednisolone Ciclosporin A Tacrolimus NNRTIs PIs

Question 26

Give an example of enzyme inducer drug?

Answer 26

Rifampicin (so giving this with a CYP450 substrate will lower levels of the substrate e.g. warfarin)

Question 27

Methotrexate toxicity symptoms?

Answer 27

It is a folate antagonist Ulcerative somatitis Leucopenia Pulmonary fibrosis Megaloblastic macrocytic anaemia

Question 28

What Carbamazepine toxicity symptoms are there?

Answer 28

Ataxia Abdo pain SIADH aplastic anaemia

Question 29

What is an example of a Salicylates?

Answer 29

Aspirin

Question 30

Aspirin toxicity symptoms?

Answer 30

Hyperventilation: - mixed resp alkalosis and met acidosis Dizziness N+V Tinnitus

Question 31

Cyanide toxicity signs?

Answer 31

Bitter almond taste in mouth tachycardia Hypertension confusion

Question 32

How to manage cyanide poisoning?

Answer 32

Vitamin B12 (hydroxycobalamin)

Question 33

Symptoms of paracetamol toxicity?

Answer 33

RUQ pain Vomiting Blood + protein in urine

Question 34

What part of the body is used to quantify drug concentration levels during a post-mortem

Answer 34

femoral vein

Question 35

What part of the body can be used to measure glucose for a post mortem?

Answer 35

Vitreous humour for glucose - identify DKA deaths

Question 36

What is the gold standard technique to identify drugs?

Answer 36

GC-MS Gas chromatography-mass spectrometry

Question 37

How long can a drug levels be identified by blood?

Answer 37

12 hours

Question 38

How long can a drug levels be identified by urine?

Answer 38

2-3 days

Question 39

How long can a drug levels be identified by hair?

Answer 39

long term drug use